CUWSS v1.0 Student Guide_Vol2

CUWSS

Conducting Cisco Unified Wireless Site Survey Volume 2 Version 1.0

Student Guide

Text Part Number: 97-2789-01

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Student Guide © 2009 Cisco Systems, Inc. All Rights Reserved.

DISCLAIMER WARRANTY: THIS CONTENT IS BEING PROVIDED “AS IS.” CISCO MAKES AND YOU RECEIVE NO WARRANTIES IN CONNECTION WITH THE CONTENT PROVIDED HEREUNDER, EXPRESS, IMPLIED, STATUTORY OR IN ANY OTHER PROVISION OF THIS CONTENT OR COMMUNICATION BETWEEN CISCO AND YOU. CISCO SPECIFICALLY DISCLAIMS ALL IMPLIED WARRANTIES, INCLUDING WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE. This learning product may contain early release content, and while Cisco believes it to be accurate, it falls subject to the disclaimer above.

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Table of Contents Volume 2 Conduct the Site Survey 3-1

Overview 3-1 Module Objectives 3-1

Producing a Predictive Site Survey 3-3 Overview 3-3

Objectives 3-3 Creating Maps 3-4 Cisco WCS Planning Mode 3-12 Summary 3-17

Conducting a Layer 1 Site Survey 3-19 Overview 3-19

Objectives 3-19 Cisco Spectrum Expert 3-20 Understanding Decibels 3-22 FFT, FFT Plots, and Spectrograms 3-25 Spectrum Expert Charts 3-38 Tools and Settings 3-47

Monitoring 3-51 Indentifying Interference and Interference Sources 3-63 Setting Up Cisco Spectrum Expert 3-71 Locate Interferers 3-77 Summary 3-87

Conducting a Layer 2 Site Survey for Data 3-89 Overview 3-89

Objectives 3-89 Attenuation Characteristics of Building Materials 3-90 Best Practices for a Data Site Survey 3-95 Create a Data Site Survey Project 3-105

The Navigation Bar 3-106 Settings Tab 3-121 Color Tab 3-125 802.11 Tab 3-126 Configuring Authentication Mechanism 3-127 Scan Tab 3-128

Configure AirMagnet Survey PRO 3-131 Conduct the Survey 3-137 Merge and Display Data 3-146 Generate a Report 3-151 Summary 3-152

Conducting a Layer 2 Site Survey for Voice Applications 3-153 Overview 3-153

Objectives 3-153 IEEE 802.11b/g/n and VoWLAN Deployments 3-154 IEEE 802.11a/n and VoWLAN Deployments 3-170 Summary 3-179

Conducting a Layer 2 Site Survey for 802.11n Clients 3-181 Overview 3-181

Objectives 3-181 Active Survey with Iperf 3-182 Iperf Download and Installation 3-183 Configuring AirMagnet for an Active Iperf Survey 3-185 Three Types of Surveys Using 802.11n Access Points 3-189 Summary 3-190

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ii Conducting Cisco Unified Wireless Site Survey (CUWSS) v1.0 © 2009 Cisco Systems, Inc.

Conducting a Layer 2 Site Survey for Location 3-191 Overview 3-191

Objectives 3-191 Minimum Signal Level Thresholds 3-192 Access Point Placement 3-193 Access Point Separation 3-194 Location, Voice, and Data Coexistence 3-197 Summary 3-199 Module Summary 3-201 Module Self-Check 3-203

Module Self-Check Answer Key 3-206

AP and Controller Density and Licensing 4-1


Determining the Infrastructure Requirements for the WLAN 4-3 Overview 4-3

Objectives 4-3 Power Requirements 4-4 Evaluating the Current Network Infrastructure 4-11 Mounting Considerations 4-12 Adding Additional Access Points 4-20

Access Point Antenna Selection 4-20 Summary 4-24

Determining the WLAN Equipment and Licenses 4-25 Overview 4-25

Objectives 4-25 Controllers and Access Points 4-26

N + 1 Redundancy Design 4-32 N + N Redundancy Design 4-33 N + N + 1 Redundancy Design 4-34

Cisco WCS Licenses for Location Servers and the MSE 4-35 Supported Operating Systems 4-37

Summary 4-42 References 4-42

Module Summary 4-43 Module Self-Check 4-45


Assessment of the Deployment 5-1


Verifying RF Coverage 5-3 Overview 5-3

Objectives 5-3 RF Audit 5-4

Roaming Control 5-5 RRM Tuning 5-8 Network Appliance and Application Tuning 5-10 Verify the Applications 5-12 Summary 5-14

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© 2009 Cisco Systems, Inc. Conducting Cisco Unified Wireless Site Survey (CUWSS) v1.0 iii

Verifying WLAN Readiness 5-15 Overview 5-15

Objectives 5-15 Cisco WCS Site Calibration 5-16 Cisco WCS Location Readiness Test 5-30 Cisco WCS Voice Readiness Test 5-32

Troubleshooting Voice RF Coverage Issues 5-33 Summary 5-34

Presenting an Installation Report 5-35 Overview 5-35

Objectives 5-35 Preparing an Installation Report 5-36 Presenting an Installation Report 5-44 Summary 5-45 Module Summary 5-47 Module Self-Check 5-49


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iv Conducting Cisco Unified Wireless Site Survey (CUWSS) v1.0 © 2009 Cisco Systems, Inc.

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Module 3

Conduct the Site Survey

Overview Depending on the type of wireless service that you plan to offer on a WLAN, the design of the wireless service can vary considerably. Placement of the wireless service and access point density differ, depending on data, voice, and location-based services. Lower power is generally used to support voice- and location-based services, as well as Radio Resource Management (RRM).

Cisco Wireless Control System (WCS) can be used to do a predictive site survey to determine access point density and placement for data, voice, and location-based services.

Before conducting a site survey of a facility, a Layer 1 sweep of the facility should be performed with Cisco Spectrum Expert to identify and mitigate anything that would interfere with the proposed WLAN access points and wireless clients.

Module Objectives Upon completing this module, you will be able to perform a site survey for data, voice, and location applications. This ability includes being able to meet these objectives:

Describe the steps necessary to use the Cisco WCS planning mode tool to produce a predictive site survey

Conduct a Layer 1 site survey using Cisco Spectrum Expert

Conduct a Layer 2 site survey for data applications using AirMagnet Survey PRO

Conduct a Layer 2 site survey for voice applications using AirMagnet Survey PRO

Conduct a Layer 2 site survey for IEEE 802.11n clients using AirMagnet Survey PRO

Conduct a Layer 2 site survey for location services using AirMagnet Survey PRO

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3-2 Conducting Cisco Unified Wireless Site Survey (CUWSS) v1.0 © 2009 Cisco Systems, Inc.

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Lesson 1

Producing a Predictive Site Survey

Overview The Cisco Wireless Control System (WCS) planning mode tool can predict the count and placement of access points. To generate a proposal, a user enters the expected wireless client user density and services to support data, voice, and location.

Objectives Upon completing this lesson, you will be able to describe the steps necessary to use the Cisco WCS planning mode tool to produce a predictive site survey. This ability includes being able to meet these objectives:

Describe the process to create a map for a predictive site survey

Describe the process that the Cisco WCS planning mode tool uses to calculate access point requirements

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Creating Maps This topic describes the process to create a map for a predictive site survey. Maps are used in Cisco WCS to give a visual representation of the Cisco Unified Wireless Networking environment. The maps feature also helps with implementations and planning.

© 2009 Cisco Systems, Inc . Al l rights reserved. CUWSS v1.0—3-2

Monitor > Maps > New Campus > Go

The campus map is used as a base for the rest of the maps. The campus is used to place buildings and to define outside areas for wireless coverage. It allows administrators to select a location based on a campus drill down to the building, and then to the floor area level.

The following steps describe the process to add a single campus to the Cisco WCS database:

Step 1 Save the map in PNG, JPG, JPEG, or GIF format.

Note The map can be any size because Cisco WCS automatically resizes the map to fit its working areas.

Step 2 Browse to and import the map from anywhere in your file system.

Step 3 Choose Monitor > Maps to display the Maps page.

Step 4 From the drop-down menu, choose New Campus and click GO.

Step 5 On the Maps > New Campus page, enter the campus name and campus contact name.

Step 6 Browse to and choose the image filename or computer-aided design (CAD) file containing the map of the campus and click Open.

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© 2009 Cisco Systems, Inc. Conduct the Site Survey 3-5

Step 7 Check the Maintain Aspect Ratio check box to maintain the aspect ratio (ratio of horizontal and vertical pixels) of the map image. Maintaining the aspect ratio prevents visual distortion of the map.

Step 8 Enter the horizontal and vertical span of the map in feet.

Note The horizontal and vertical span should be larger than any building or floor plan to be added to the campus.

Step 9 Click OK to add this campus map to the Cisco WCS database. Cisco WCS displays the Maps page, which lists maps in the database, map types, and campus status.

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© 2009 Cisco Systems, Inc. All rights reserved. CUWSS v1.0—3-3

Monitor > Maps > New Campus > Go

Maps can start as either a campus or building, but only a campus will provide an outdoor coverage area. A building can be added as a single entity or as part of a campus.

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Adding a New Building

Buildings can be created as standalone entities, or they can be added to a campus. If the buildings are standalone, then outdoor areas cannot be created. Buildings are used to define floor areas that are used to deploy access points.

To create a building, follow these steps:


Step 2 Click the desired campus name. Cisco WCS displays the Maps > Campus Name page.

Step 3 From the drop-down menu, choose New Building and click GO.

Step 4 On the Campus Name > New Building page, enter the building information to create a virtual building in which to organize related floor plan maps:

Name: The user-defined name of the building

Contact: User-defined contact name

Floors: The number of above-ground floors contained in the new building

Basements: The number of basements contained in the new building

Horizontal Span: Horizontal measurement (left to right) of the building rectangle, in feet or meters

Vertical Span: Vertical measurement (up and down) of the building rectangle, in feet or meters

Tip The horizontal and vertical span should be larger than or the same size as any floors that you might add later. You can also use Ctrl-click to resize the bounding area in the upper left corner of the campus map. As you change the size of the bounding area, the Horizontal Span and Vertical Span parameters of the building change to match your actions.

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Step 5 Select Place to put the building on the campus map. Cisco WCS creates a building rectangle scaled to the size of the campus map.

Step 6 Click the building rectangle and drag it to the desired position on the campus map.

Note After adding a new building, you can move it from one campus to another without having to re-create it.

Step 7 Click Save to save this building and its campus location to the database. Cisco WCS saves the building name in the building rectangle on the campus map.

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Adding a New Floor

Floor areas are where administrators can get a view of the wireless environment and track device location, as well as to see trouble with the network. After you add a building to a campus map, you can add individual floor plan and basement maps to the building. Follow these steps to add floor plans to a campus building:

Step 1 Save your floor plan maps in PNG, JPG, or GIF format.

Note The maps can be any size because Cisco WCS automatically resizes the maps to fit the workspace.

Step 2 Browse to and import the floor plan maps from anywhere in your file system. You can also import CAD image files DXF and DWG.

Note An imported AutoCAD file can become blurred when you zoom. Without the zoom, the clarity is about the same as the original AutoCAD file. Make sure all relevant sections are clearly visible in the original AutoCAD file (DWG or DXF) and then import the AutoCAD file into PNG or GIF format rather than JPEG or JPG.


Step 4 Click the desired campus name. Cisco WCS displays the Maps > Campus Name page.

Step 5 Move your cursor over the name within an existing building rectangle to highlight it.

Step 6 On the Building Name > New Floor Area page, add the following parameters:

Floor Area Name: User-defined floor area or basement name.

Contact: User-defined contact name.

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Floor: Choose the floor or basement number.

Floor Type (RF Model): The options are: Cubes and Walled Offices, Drywall Office Only, or any other user-defined RF model.

Floor Height (feet or meters): Enter the ceiling height of the floor.

Image File: Name of the file containing the floor map.

Step 7 Check the Image File check box; then browse to and choose the desired floor or basement image filename and click Open.

Step 8 Click Next.

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Monitor > Maps > Building > New Floor > Area > Go > Next

Note When you choose the floor or basement image filename, Cisco WCS displays the image in the building-sized grid.

If you imported a CAD file, you are directed to the image conversion page.

Note The length of time for the conversion varies and depends on the file size, file detail, and number of layers in the file.

Step 9 Either leave the Maintain Aspect Ratio check box checked to preserve the original image aspect ratio, or uncheck the check box to change the image aspect ratio.

Step 10 Enter an approximate floor or basement horizontal span and vertical span (width and depth on the map) in feet.

Note The horizontal and vertical span should be smaller than or the same size as the building horizontal span and vertical span in the Cisco WCS database.

Step 11 If desired, click Place to locate the floor or basement image on the building grid.

Tip You can use Ctrl-click to resize the image within the building-sized grid.

Step 12 Click OK to save this floor plan to the database. Cisco WCS displays the floor plan image on the Maps > Building Name page.

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Cisco WCS Planning Mode This topic describes how to use the Cisco WCS planning mode tool to calculate access point requirements. The Cisco WCS planning mode tool enables you to calculate the number of access points that are required to cover an area, by placing fictitious access points on a map and viewing the coverage area.


Cisco WCS Planning ModeCalculate the recommended number and location of lightweight access points.Criteria:– Traffic type active on the network:

DataVoiceLocation servicesAll of the above

– Number of the following:Active usersUsers per square footage

Note: Walls are not used or accounted for in planning mode calculations.

Based on the throughput specified for each protocol (IEEE 802.11a/n or IEEE 802.11b/g/n), the planning mode tool calculates the total number of access points required to provide optimum coverage in your network. You can calculate the recommended number and location of access points based on the following criteria:

Traffic type active on the network: data, voice traffic, or both

Location accuracy requirements

Number of active users

Number of users per square footage

Note Walls are not used or accounted for in planning mode calculations.

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Planning Mode

To calculate the recommended number and placement of access points for a given deployment, follow these steps:

Step 1 Choose Monitor > Maps.

Step 2 Click the appropriate location link from the list that appears.

Step 3 Choose Planning Mode from the drop-down menu (top-right) and click GO. A blank floor map appears.

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Add Access Points

Step 4 Click Add APs.

Step 5 In the page that appears, drag the dashed-line rectangle over the map location for which you want to calculate the recommended access points.

Note Adjust the size or placement of the rectangle by selecting the edge of the rectangle and holding down the Ctrl key. Move the mouse as necessary to outline the targeted location.

Step 6 Select Automatic from the Add APs drop-down menu.

Step 7 Select the AP Type and the appropriate antenna and protocol for that access point.

Step 8 Select the target throughput for the access point.

Step 9 Check the boxes next to the services that will be used on the floor. Options are Data/Coverage (default), Voice, and Location.

Note You must select at least one service or an error occurs.

Note If you check the Advanced Options check box, two additional access point planning options appear: Demand and Override Coverage per AP. Additionally, a Safety Margin parameter appears for the Data/Coverage and Voice service options.

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Advanced Options and Safety MarginsSelect the desired option to qualify relative signal strength requirements for data and voice services in the access point calculation.– Options are: Aggressive, Safe, Very Safe, and 7920-enabled.

Select Aggressive to require minimal signal strength requirements in the calculation and Very Safe to request the highest signal strength.The safety margins for each option are as follows:– Aggressive: Minimum (-3 dBm)– Safe: Medium (0 dBm)– Very Safe: Maximum (+3 dBm)

These can be applied for data only, data and voice only, or voice only.Select Demand if you want to use the total number of users or user ratio per access point as a basis for the access point calculation.

If you check the Advanced Options check box, you can select the desired safety margin of the signal strength threshold for data.

There are three safety margins:

Aggressive: –3 dBm

Safe: 0 dBm

Very Safe: +3 dBm

If voice traffic is transmitted on the WLAN, select one of the following:

Aggressive: Minimum (–78 dBm [802.11a/b/g/n])

Safe: Medium (–75 dBm [802.11a/b/g/n])

Very Safe: Maximum (–72 dBm [802.11a/b/g/n])

7920_enabled: (–72 dBm [802.11a/n]; –67 dBm [802.11b/g/n])

Demand: Select if you want to use the total number of users or user ratio per access point as a basis for the access point calculation.

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Calculate Access Points

Step 10 Click Calculate, to obtain the recommended number of access points, given the selected services and parameters.

Note Recommended calculations assume the need for consistently strong signals unless adjusted downward by the safety margin advanced option. In some cases, the recommended number of access points is higher than what is required.

Step 11 Click Apply to generate a map that shows proposed deployment of the recommended access points in the selected area based on the selected services and parameters.

Step 12 From the heat map, choose Generate Proposal. The Generate Proposal feature allows you to create a Cisco Unified Wireless Networking proposal, using the information gathered from the map and planning tool. It will give information on how the planning was done and which mode was used. It also prints out the heat map so that the coverage can be seen and verified. The proposal allows administrators to present a proposal easily without having to do a large amount of manual drawing and editing.

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Summary This topic summarizes the key points that were discussed in this lesson.


SummaryCampuses, buildings, and floor plans can be entered into the Cisco WCS database.The planning mode tool can generate a proposal to display textual and graphical recommendations for access point count and placement.

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Lesson 2

Conducting a Layer 1 Site Survey

Overview Cisco Spectrum Expert monitors the RF spectrum used by a variety of wireless network and communications technologies, such as Wi-Fi (IEEE 802.11) WLANs. Cisco Spectrum Expert consists of a hardware-based Spectrum Sensor card and GUI-based software installed on a workstation, which provides complete visibility of the RF environment in which wireless network technologies operate.

Cisco Spectrum Expert can identify almost all sources of RF activity in the unlicensed 2.4-GHz and 5-GHz bands. A variety of RF devices that can cause interference include cordless phones and headsets, Bluetooth devices, and microwave ovens. Based on this data, network engineers can take steps to increase network performance and security in the face of interferers, network congestion, and security attacks.

Objectives Upon completing this lesson, you will be able to conduct a Layer 1 site survey using Cisco Spectrum Expert. This ability includes being able to meet these objectives:

Introduce Cisco Spectrum Expert for Wi-Fi

Describe the relationship between decibel and the power measured in milliwatts and watts

Describe FFT, FFT plots, and spectrograms

Describe Cisco Spectrum Expert charts

Describe the different settings and tools available in the Cisco Spectrum Expert product

Identify interference and interference sources using Cisco Spectrum Expert

Describe the necessary steps to set up Cisco Spectrum Expert

Describe how to locate interference sources using Cisco Spectrum Expert

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Cisco Spectrum Expert This topic introduces Cisco Spectrum Expert for Wi-Fi. Cisco Spectrum Expert addresses the problem of RF interference in wireless networks. With Cisco Spectrum Expert, you can detect, classify, locate, and mitigate sources of wireless interference to optimize network performance for mobility applications.


What Is Cisco Spectrum Expert?It is a hardware- and software-based spectrum analyzer solution.It shows all spectral activity in the frequency domain, not just Wi-Fi-based transmitters.Each sensor contains a powerful spectrum-analyzer on a chip (SAgE).Spectrum Expert software analyzes data from the sensor card and provides a GUI-based view of the network and RF activity.It provides a real-time assessment of the W i-Fi physical layer, Layer 1.

Cisco Spectrum Expert Wi-Fi is the first solution in the industry that allows for comprehensive visibility at the RF physical layer, that is, the RF spectrum, which is the actual backbone of any Wi-Fi deployment. Similar to the application of a traditional cable tester, Cisco Spectrum Expert Wi-Fi not only allows you to test the viability of your wireless network but also gives you insight into what is actually going on in the spectrum. The Cisco Unified Wireless Network supports real-time spectrum intelligence for Wi-Fi networks. This solution detects, classifies, and locates devices causing RF interference in the unlicensed 2.4-GHz and 5-GHz bands. For this solution, the Cisco Wireless Control System (WCS) works in conjunction with Cisco Spectrum Expert Wi-Fi to provide visibility into non-Wi-Fi interference sources that may cause wireless performance degradation. When the source of the interference is determined, you can remove, move, shield, adjust, or replace the interference source.

Cisco introduced RF spectrum intelligence capabilities with Cisco Unified Wireless Network Software Release 4.1. Additional enhancements are delivered in Cisco Unified Wireless Network Software Release 4.2. To implement the full Cisco Spectrum Intelligence solution, organizations must be running Cisco WCS Software Release 4.2 or later and add a Cisco WCS Spectrum Intelligence license and one or more Cisco Spectrum Expert Wi-Fi sensors, Software Release 3.2 and later. A Cisco WCS Spectrum Intelligence license is required to operate Cisco Spectrum Expert Wi-Fi with Cisco WCS.

Cisco Spectrum Expert is a combination of both hardware and software. Cisco Spectrum Expert is delivered as hardware in a PC card (CardBus) form factor and is a software install.

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You can take advantage of Cisco Spectrum Expert by simply putting the card in your PC-compatible laptop PC card slot and running the Cisco Spectrum Expert management console software.

The Cisco Spectrum Expert consists of two primary components:

Sensor card: The Sensor cards provide the hardware foundations for Cisco Spectrum Intelligence. Each Sensor card incorporates Spectrum Analysis Engine (SAgE) ASIC, a powerful spectrum-analyzer-on-a-chip. SAgE provides better visibility into the RF spectrum and can easily identify and detect sources of wireless interference.

Cisco Spectrum Expert software: The Cisco Spectrum Expert software analyzes data from the Sensor card and provides a GUI-based view of network and RF activity.

With Cisco Spectrum Expert, the Sensor card and application are integrated into one convenient platform. You can use the application device finder mode to observe how the signal strength from an interferer varies as you move about the enterprise. This makes it possible to quickly pinpoint the location of the interfering device.

As a first step in the spectrum analysis process, the ambient RF environment must be scanned and analyzed to determine the sources of RF activity in the neighborhood of the network, especially causes of interference or other problems.

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Understanding Decibels This topic describes the relationship between decibel (dB) and the power measured in milliwatts and watts.


Understanding dBdBm is a measure of absolute power output.Formula: – dBm = 10 * log(10) = 10

(Power in milliwatts)An increase of 10 dBm means 10 times the output power.Example:– 0 dBm = 1 mW– 10 dBm = 10 mW– 20 dBm = 100 mW– 30 dBm = 1 W

The decibel measures the power of a signal as a function of its ratio to another standardized value. The abbreviation for decibel is often combined with other abbreviations in order to represent the values that are compared.

Here are two examples:

dBm: dBm represents the power level compared to one milliwatt (mW).

dBw: dBw represents the power level compared to one watt (W).

You can calculate the power in decibels from this formula:

Power (in dB) = 10 * log(10) = 10 (signal/reference)

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Understanding dB (Cont.)dB is a relative power measurement; 1 meter distance results in a 40 dB loss.Every 2x increase indistance = 10 dB loss indoor (6 dB loss outdoor)Example (indoor):– 2 meters = 50 dB loss– 4 meters = 60 dB loss– 8 meters = 70 dB loss

This list defines the terms in the formula:

log10 is logarithm base 10.

Signal is the power of the signal (for example, 50 mW).

Reference is the reference power (for example, 1 mW).

Here is an example. If you want to calculate the power in decibels of 50 mW, apply the formula as follows:

Power (in decibels) = 10 * log10 (50/1) = 10 * log10 (50) = 10 * 1.7 = 17 dBm

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How to Use dBm and dB802.11 devices typically operate well at receive strengths down to –85 dBm.Received strength depends on these factors:– Output power of transmitter– Distance from receiver

Example:– Access point transmits at 20 dBm.– Station is 32 meters from access point.– Received signal is as follows:

+20 dBm output power, –90 dB loss = –70 dBm received power

Because decibels are ratios that compare two power levels, use simple math to manipulate the ratios for the design and assembly of networks. For example, you can apply this basic rule to calculate logarithms of large numbers:

log10 (A*B) = log10(A) + log10(B)

Using the formula, you can calculate the power of 50 mW in decibels as follows:

Power (in dB) = 10 * log10 (50) = 10 * log10 (5 * 10) = (10 * log10 (5)) +

(10 * log10 (10)) = 7 + 10 = 17 dBm

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FFT, FFT Plots, and Spectrograms This topic describes fast Fourier transform (FFT), FFT plots, and spectrograms. The spectrum plots use graphical displays to provide detailed, low-level views of the RF spectrum. This topic describes the information displayed in each plot, including the Swept Spectrogram, which can be used to obtain a more fine-grained view of spectrum activity.


What Is an FFT?A fast Fourier transform is an efficient algorithm to compute the discrete Fourier transform.Fast Fourier transform is characterized as follows:– Named after Joseph Fourier– An integral transform that re-expresses a function in terms of

sinusoidal basis functions– For example: Sum or integral of sinusoidal functions multiplied by

some coefficients ("amplitudes") Fourier transforms have many scientific applications. In signal processing and related fields, the Fourier transform is typically thought of as decomposing a signal into its component frequencies and their amplitudes.DFT is a form of Fourier transform suitable for use in computer-based computations.

FFT is an efficient algorithm to compute the discrete Fourier transform (DFT) and its inverse. FFTs are of great importance to a wide variety of applications, from digital signal processing to solving partial differential equations to algorithms for quickly multiplying large integers.

Discrete Fourier transform, occasionally called the finite Fourier transform, is a transform for Fourier analysis of finite-domain discrete-time signals. It is widely employed in signal processing and related fields to analyze the frequencies contained in a sampled signal, to solve partial differential equations, and to perform other operations such as convolutions. The DFT can be computed efficiently in practice using an FFT algorithm.

Because FFT algorithms are so commonly employed to compute the DFT, the two terms are often used interchangeably in colloquial settings, although there is a clear distinction: DFT refers to a mathematical transformation, regardless of how it is computed, while FFT refers to any one of several efficient algorithms for the DFT. This distinction is further blurred, however, by the synonym finite Fourier transform for the DFT, which apparently predates the term fast Fourier transform.

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Time Domain vs. Frequency DomainThe “Frequency Domain” is the inverse of the time domain.

A time domain graph shows how a signal changes over time.A frequency domain graph shows how much of the signal lies within each given frequency band over a range of frequencies.Represents one pure tone or one pure color.Continuous in time.Highly simplified—no signals are this pure.Transforms into a signal at one discrete frequency.Instantaneous in frequency.

Time domain is a term used to describe the analysis of mathematical functions, or physical signals, with respect to time. In the time domain, the signal or function value is known at various discrete time points, or for all real numbers in the case of continuous time. An oscilloscope is a tool commonly used to visualize real-world signals in the time domain.

Frequency domain is a term used to describe the analysis of mathematical functions or signals with respect to frequency.

A time domain graph shows how a signal changes over time, whereas a frequency domain graph shows how much of the signal lies within each given frequency band over a range of frequencies. A frequency domain representation can also include information on the phase shift that must be applied to each sinusoid in order to be able to recombine the frequency components to recover the original time signal.

The frequency domain relates to the Fourier transform or Fourier series by decomposing a function into an infinite or finite number of frequencies. This is based on the concept of Fourier series, that any waveform can be expressed as a sum of sinusoids, sometimes an infinite number.

A spectrum analyzer is the tool commonly used to visualize real-world signals in the frequency domain.

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FFT PlotsBased on SAgE hardware Comparable to what you see on a real-t ime spectrum analyzer– x-axis is frequency– y-axis is power in dBm

Trace types:– Real-time FFT: Average Power, Max Power, Max Hold (software derived)– FFT Duty Cycle: Separate plot type because y-axis is not dBm

What are FFT plots good for?– Seeing overall spectrum activity (average power, duty cycle)– Seeing frequency hoppers (maximum power)– Seeing intermittent signals (maximum hold)

What are the limitations?– Resolution bandwidth fixed at 160 KHz– Cannot see very narrow signals

FFT plots are based on SAgE hardware. Raw spectrum data is collected on the SAgE chip inside the sensor, and statistical analysis is performed directly onboard by the SAgE hardware. This enables very fast analysis of large quantities of spectrum data, but with the limitation that the parameters of the analysis are hard-coded into the design of the SAgE chip.

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Example of Real-Time FFT Plot

Average Power

Max Hold

Devices

Max Power

A Real-Time FFT plot displays RF power as a function of frequency, a Fourier transform of the RF spectrum. The data is direct data from SAgE. The plot can provide three different views: the average power (Avg) read during the most recent measurement interval; the maximum power (Max); or the maximum power detected at any time since the plot began running (Max Hold). You can also display the integrated channel power for each RF channel in Real-Time FFT plots on a trace-by-trace basis by clicking the Channels On radio button in the Control Panel and using the Show Power drop-down box to select which channel trace should display the Integrated Channel Power.

The example shows the following:

Max power on the channel at the time of sweep

Average power on the channel at the time of sweep

— By hovering the mouse over the channel you can see what devices have been detected on the channel

Max Hold gives you a reading of the maximum amount of power used on the channel during the trace.

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Example of FFT Duty Cycle Plot

100% Busy

45% Busy

The FFT Duty Cycle plot displays the percentage of the time that the ambient RF signal is 20 dB above the noise floor. This is represented on a per-frequency bin basis. The FFT Duty Cycle plot includes all RF energy, both from 802.11 devices and interferers.

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FFT Plot ControlsFrequency selection– Center Frequency/Span– Start Frequency/Stop Frequency– 802.11 channel

Band selection– 2.4 GHz or 5 GHz

The plot Control Panel lets you fine-tune the data presented by the plots. Each plot has its own plot-appropriate controls. However, many of these controls are common to more than one plot.

Several plots provide measurements of RF power (average power, maximum power, and so on) as a function of frequency. The RF frequencies are presented as a range across the horizontal axis. Frequency settings enable you to establish the range of the x-axis. Even for the time-based plots, however, you can set the band or channel that Spectrum Expert will monitor.

You can select the frequency to be monitored based on a center frequency and span, start or stop frequency, or based on specific channels. Use the Band/Channel drop-down menu to select a particular band or channel to monitor.

Once you have made a selection, the console automatically fills in default values for the center frequency and span, or the start and stop frequency. However, you can edit these default values.

If you change the default center frequency and frequency span, or the start and stop frequencies, you may no longer be plotting entirely in-channel or in-band. However, Spectrum Expert will not permit you to set frequencies that are outside the hardware capabilities of the sensor technology. In this sense, the technology is error-proof.

You can change the bands available, that is, the bands shown on the Frequency menus, by changing the Monitored Bands settings by navigating to Tools > Settings > Monitored > Bands.

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FFT Plot Controls (Cont.)Amplitude– Reference Level: Sets top power

level of plot– Vertical Scale: How many dB per

block– Auto Scale: Automatically adjusts

reference and scaleChannels– Marks where 802.11 channels start

and stopShow Devices– Displays devices affecting channel

on mouse-over

Amplitude settings enable you to set the scale for the vertical axis. The exact measurements will depend on the type of measurement being made. For example, RF power measurements are in decibels compared to 1 mW (dBm), while duty cycle measurements are in percentages (because the duty cycle is typically defined as the percentage of time an RF signal is above some threshold value, or the percentage of time an RF signal is detected from a network device or interferer). The Amplitude settings include the following choices:

Reference Level refers to the value at the top of the vertical axis.

Vertical Scale refers to the change in value represented by each tic-mark on the vertical axis.

If you select Auto Scale, the application automatically selects the optimum calibration for the vertical scale, based on recent power measurements.

You can turn the display On or Off using the Channels radio buttons. The channels shown will be the channels appropriate for the band that you are currently monitoring, taking into account any Regulatory Domains you have selected under Channel Settings. The On and Off radio buttons allow you to enable or disable the display of devices associated with each channel as you pass your mouse over the frequency trace in a plot.

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MarkersUseful for obtaining exact measurementsCan move X-position of marker with mouseY-position follows current selected trace valueUse Peak Search to control markerSingle marker mode:– Reads out X, Y values for position

of markerMarker delta mode:– Reads out X, Y difference

between two markers

A marker is a small icon on the plot that rides the graph at a particular point along the x-axis, in other words, at a particular frequency. The marker moves up and down according to the movement of the graph at that fixed point. There is a peak search function for setting the marker. The value can be manually input, which is useful for placing a marker on the plot where an interferer is being reported. This helps to see the waveform.

The fields in the window are as follows:

On / Off: Indicates whether the marker is on or off, that is, whether it is in use.

Type: A Single marker is just that, one marker that rides the trace. If you select Delta, you will initially still see a single marker on the plot. However, with a quick “mouse hand,” you can grab the marker with your mouse cursor (click and hold on the marker), and slide the marker to a second location on the plot. You now have two markers riding the trace, so that you can see the difference in behavior between two different frequencies.

Value: Indicates the point along the x-axis (the frequency or time axis) where the marker should ride the plot.

Trace: For plots that allow more than one trace, use the drop-down menu to select which of the traces that the marker will ride.

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Swept SpectrogramSame data as Real-Time FFT and Duty CycleShows data over timex-axis is frequencyy-axis is time (in sweeps) – Newest data at the bottom of the graph

Color intensity indicates power level (or duty cycle)Useful for getting a visual understanding of what is going on in the spectrum over time– Good for seeing frequency hoppers– Frequency shifts– Intermittent

Displays different modes– Maximum– Average– Duty Cycle

The Swept Spectrogram is a different presentation of the data shown in the Real Time FFT and FFT Duty Cycle plots. Each colored horizontal line in the Swept Spectrogram plot displays the RF power or duty cycle as a function of frequency, as measured over the time of one sweep in time (typically one second). The power or duty cycle values in each sweep are mapped to a range of colors and displayed in a scrolling or waterfall display. This allows you to observe the FFT signals over historical time and easily see signals with shifting frequencies and various durations.

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Example of Swept Spectrogram—Max

Little to No Activity

Constant Power

Higher Power Bursting over Time

The Swept Spectrogram plot uses colors to represent RF power levels. The Color Scale options enable you to map the highest color and lowest color to specific power levels. In this example, the color blue has been mapped to –108 dBm, while red has been mapped to –62 dBm. Values below the minimum value (–110 dBm, in this case) are automatically mapped to purple, while values above the maximum value (–30 dBm here) are automatically mapped to white.

For the Swept Spectrogram, the color scale is only visible when there is enough room to display it on screen. Depending on how many plots you have open, and on your display monitor resolution, you may need to close some plots to see the color scale.

Auto Scale chooses appropriate upper and lower values based on recent power measurements.

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Power vs. FrequencyBased on software display analysisSimilar to output from a traditional Spectrum AnalyzerBased on a single snapshot of data (unlike FFT plots)Resolution bandwidth adjustable down to 10 KHzTrace types:– Normal: Single measurement– Average: Averaged over time– Max Hold: Highest value seen over time

What it is good for:– Seeing narrow-band devices– Averaging data over long times

Limitations:– Hard to catch devices that are intermittent transmitters

The Power vs. Frequency plot is also, in essence, a Fourier transform of the RF spectrum, showing the amount of RF power detected at various frequencies. The difference between the Power vs. Frequency plot and the Real-Time FFT plot is that the Power vs. Frequency plot is generated based on an analysis of SAgE data. This means that data can be aggregated and combined in various ways that are not possible with direct SAgE data, the basis for the Real-Time FFT plot. The software-based Power vs. Frequency calculations generate only one FFT per second. That one FFT is shown in the Power vs. Frequency plot (which is updated once per second, to reflect the new FFT).

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Example of Power vs. Frequency Plot

Max hold trace

Normal trace

You can use the Power vs. Frequency plot to display the integrated channel power for each RF channel in Real-Time FFT plots on a trace-by-trace basis by clicking the Channels On radio button in the Control Panel and using the Show Power drop-down list to select which channel trace should display the Integrated Channel Power.

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Power vs. TimeBased on software DSP analysisSimilar to output from a traditional Spectrum Analyzer (zero span mode)X-axis is time, Y-axis is powerCan select center frequency and resolution bandwidth– RBW up to 20 MHz– Accurate channel power measurement

Sweep Time (how much data to capture): – 10 microseconds to 10 milliseconds

Trigger types: When to start the capture– Free Run – Take arbitrary snapshots– Single – Trigger one time on an energy burst– Continuous – Trigger repeatedly on energy bursts

Threshold – How much power to triggerDelay – How much data to show before/after trigger eventWhat it is good for:– Capturing the power profile of a specific burst (example packet)– Accurately measuring channel power

The Power vs. Time plot displays RF power as a function of time. The time scales involved are very brief microseconds or milliseconds, so the plot is mainly used to observe RF pulse activity.


Example of Power vs. Time Plot

The Power vs. Time plot displays RF power as a function of time. The time scales involved are very brief microseconds or milliseconds, so the plot is mainly used to observe RF pulse activity.

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Spectrum Expert Charts This topic describes Cisco Spectrum Expert charts. The Cisco Spectrum Expert uses bar, line, and pie charts to provide broad summary information about activity in the RF spectrum. This topic explains the kinds of information displayed in each chart.


Spectrum Expert ChartsCoordinate three types of information in various views– Classified Devices– Channel Utilization– Channel Power

Displayed for current intervals or over historic rangesChart data differs slightly from Real-Time FFT, data is updated at 20 second intervals directly from the sensorTime based charts use direct updates for time periods < eight hoursFor time periods >= eight hours, the application averages the data over 15 minute intervals. Maximum, Average, and Minimum values are then available as options for the chart.Charts are intended to provide an overall analysis of the environment, real-time tracking should be done in the FFTs.

The Spectrum Expert spectrum charts use bar, line, and pie charts to provide broad summary information about activity in the RF spectrum. Like the spectrum plots, the spectrum charts are based on data from the SAgE chip embedded in the sensor.

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Spectrum Expert Charts (Cont.)Default charts are included in the AQ tab, others can be added by right clicking anywhere in the spectrum tab and selecting the menuUp to nine plots and charts can be configured per spectrum tab

Add Chart Active DevicesDevices Vs. ChannelDevices Vs. TimeChannel UtilizationChannel Utilization Vs. TimeInterference powerSNR

Spectrum View offers seven different types of charts, as follows:

Active Devices

Devices vs. Channels

Devices vs. Time

Channel Utilization

Channel Utilization vs. Time

Interference Power

Signal-to-noise ratio (SNR)

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Spectrum Expert Charts (Cont.)Active devices– Pie chart of all active devices in the spectrum

Chart options in the Control Panel allow for band selection as well as a channel range to be displayed.

The Active Devices shown in a pie chart drawn from the data represents the percentages owned by each RF source. You can select which channel or band to monitor.

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The Devices vs. Channel stacked chart displays the number of devices per channel and frequency band. In addition, each device is represented by a unique color and is displayed per channel.

A legend showing the devices and their associated colors is located at the top of the screen. Consequently, each colored section of the graphed bars map to the device legend.

The height of the bar shows the maximum power of all interference signals. Each color segment shows the contribution of a specific device type to the maximum power.

In the figure, channel 2 only identifies one device, which is a cordless phone shown in the color orange. Moreover, channel 1 shows two different types of devices, each identified with its unique color. You can select which frequency bands or channels will be monitored.

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The Device vs. Time line chart displays the number of devices detected at different times. You can select the time interval of interest (ranging from 10 minutes up to 24 hours), the channel or band to monitor, and the types of devices which will be tracked on the plot.

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The Channel Utilization bar chart displays RF duty cycle as a function of channel activity. You can select which frequency bands or channels will be plotted. Devices and other sources of interference are displayed by name for quick and easy identification. This Channel Utilization chart identifies RF emitters in various ranges. A stacked chart displays RF duty cycle as a function of channel.

On the Channel Utilization charts, the colored bars indicate the power level for each channel. Each interfering device is represented by a different color. A legend showing the devices and their associated colors is located at the top of the screen. Consequently, each colored section of the graphed bars map to the device legend.

The height of the bar shows the maximum power of all interference signals. Each color segment shows the contribution of a specific device type to the maximum power.

The Channel Utilization window provides these key points:

You can configure warnings and critical thresholds by navigating to Settings > Alerts.

It is useful for an overall evaluation of spectrum bandwidth.

Utilization is calculated from the duty cycle, therefore the chart is not real-time.

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The Channel Utilization vs. Time line chart displays RF duty cycle as a function of time. You can select the time interval of interest (ranging from ten minutes up to 24 hours), and the channel or band to monitor. For longer time intervals, you can also select how data is aggregated, that is, you can track the average duty cycle, the maximum duty cycle, or the minimum duty cycle.

The Channel Utilization vs. Time window provides these key points:

You can select up to four channels.

You can select warning and critical thresholds by navigating to Tools > Settings.

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The Interference Power stacked chart shows the power for each selected channel. The height of the bar shows the maximum power of all interference signals. Each bar consists of several lines representing the signal strength of a specific device type. The receive signal strength of the strongest In-Network Wi-Fi access point on each channel is shown by a + (plus) sign. The Wi-Fi noise floor is represented by a horizontal line across the grid background.

The x-axis shows the channels, and the y-axis shows the signal strength (from –100 dBm to 0 dBm). The height of the bar indicates the cumulative power (in dBm) for all devices in this category that affect a given channel.

You can view channel and power information as follows:

Place the mouse to hover over a stacked bar to view pop-up information about the channel, maximum power, and the signal strength of each interfering device. Or, place the mouse to hover over a + sign to view pop-up information about the channel and the signal strength of the strongest in-network Wi-Fi access point.

Right-click either a stacked bar or + sign to view the same pop-up menu available on the Devices vs. Channel chart.

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The SNR chart displays the signal-to-noise ratio for each channel having access points. SNR is the ratio of a given transmitted signal to the background noise on the channel.

The x-axis shows the channels and the y-axis shows the SNR power level (from –50 dB to 50 dB). The height of the bar above or depth of the bar below the 0 dB line indicates the SNR (in dB) for a given channel.

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Tools and Settings This topic describes the different settings and tools available in the Cisco Spectrum Expert product. The Cisco Spectrum Expert has many tools and settings.

The Tools menu provides access to the Settings dialog.

The Sensors and Antennas menu offers the following options:

Sensors and Antennas

Console Settings

Band and Channel Settings

Alert Settings

Cisco WCS Settings

To modify which Spectrum Sensor or antennas are used by Cisco Spectrum Expert, navigate to Tools > Settings.

The Sensor Setup panel should be displayed by default. If it is not, select Sensors and Antennas on the toolbar at the left.

Select the Sensor card and antenna combination from these choices:

Sensor Card with Internal Antenna: Tells the application to use data from the internal Sensor card. Also tells the Sensor to use its internal antenna.

Sensor Card with External Antenna: Tells the application to use data from the internal Sensor card. Also tells the Sensor to use its external antenna.

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The key points include the following:

Sensors and antennas

— Allow selection of internal or external antenna

— Control a hardware switch

— If external antenna attached, but internal selected, then internal will be used

An external antenna should always be used.

— Better gain

— Better separation from the noisy laptop

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The Console Settings enable you to fine-tune how the Cisco Spectrum Expert console displays data. Navigate to Tools > Settings. From the toolbar on the left, select Console Settings.

You can change the following settings:

Spectrum View Configuration for Playback: Choose to load the spectrum views from the capture file, or retain your settings for viewing the capture file.

Date Formats Used Throughout the Application: Select from the drop-down menu.

Instant Replay: Check the check box and the number of minutes (1 to 60) that you want available for use as an instant replay.

Default AP Category: In-Network or Unknown.

— Select the category that you want all APs to be initialized in by default.

— Reading the help file on this is highly recommended.

— For most applications, the default of In-Network will be used.

Plot’s Background Color: Choose Black or White as the background color.

Choose OK to confirm your changes and close the dialog box. You can also apply your changes and leave the dialog box open for further work.

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You can select band and channel settings by Regulatory Domain, or define the bands and channels individually by selecting the User Defined option. Follow these steps to configure the bands and channels that Cisco Spectrum Expert software will monitor and report on:

Step 1 Navigate to Tools > Settings.

Step 2 From the tool bar on the left, select Band and Channel Settings.

Step 3 From the Regulatory Domain pane, in the drop-down menu, select the regulatory domain to monitor. The options are as follows:

For Wi-Fi, the options include: Americas/Australia; Europe, Middle East, and Africa (EMEA); Asia/Pacific; Japan; All Wi-Fi Channels.

For Wi-Fi, it is further possible to select the Wi-Fi standard to be covered (802.11a, 802.11b/g, or both), using the check boxes.

The single regulatory domain pick will apply to both Wi-Fi standards.

Note The controls in the Monitored Bands and Channels pane also display the bands and channels that will be monitored when a Regulatory Domain is picked.

Step 4 Click OK to confirm your changes and close the dialog box. You can also click Apply to apply your changes, while leaving the dialog box open for further work.

Note Regulatory Domains are subject to change without notice.

To use the User Defined option to select the bands and channels, follow these steps:


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Step 2 From the tool bar on the left, select Band and Channel Settings.

Step 3 From the Regulatory Domain pane drop-down menu, choose the User Defined option.

Step 4 When you choose User Defined, the individual band and channel monitoring check boxes are enabled and you can select the bands and corresponding channels to monitor.

Step 5 Select one or more of the available bands from the Monitored Bands and Channels control pane.

Step 6 Select one or more of the available channels check boxes for each band selected.

Step 7 Click OK to confirm your changes and close the dialog box. You can also click Apply to apply your changes, while leaving the dialog box open for further work.

Monitoring The Sensor card is capable of monitoring up to 1 GHz of RF bandwidth at a time. In practice, however, monitoring this much of the spectrum results in some performance issues for Cisco Spectrum Expert software.

The Band and Channel settings enable you to determine how much bandwidth is actually monitored by the Sensor card. Monitoring only the bandwidth you need to monitor rather than trying to have the Sensor card scan its full potential range will result in more effective system performance.

If you change the settings for monitored bands and channels, the Cisco Spectrum Expert software automatically restarts, clearing all internal buffers. The display does not close down, but you lose any data currently shown on the spectrum plots, Channel Summary, Devices View, and so on.

The bands and channels that you define determine which bands and channels are available for selection on the spectrum plots. If you select two bands that are adjacent or which overlap (for example, 5.47 to 5.725 GHz, and 5.725 to 5.850 GHz), Cisco Spectrum Expert software will automatically consolidate the two bands into one band.

You can select one or more of the bands, such as the 2.4- to 2.5-GHz band and the 5.15- to 5.35-GHz band (for Wi-Fi). Selecting all or most of the bands shown may result in reduced performance or data quality. Select only those bands that are essential for your current monitoring and testing needs.

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The Settings - Alerts window is used to configure security and performance alerts, and consists of three tabs:

Active Devices: This tab is used to enable or disable a security alert for an interferer type or category. Security alerts can be enabled or disabled for one, multiple, or all interferer categories.

Spectrum: This tab is use to enable or disable alerts.

Channel Summary: This tab is used to enable or disable alerts for channel devices being displayed on the Channel Summary view.

The Spectrum tab controls these thresholds that are visible in charts:

Channel Utilization

Interferers Channel Utilization

SNR

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To enable alerts for active devices, follow these steps:

Step 1 Select the Active Devices tab.

Step 2 Check the Enable Performance Alerts check box.

Step 3 Check Alert only if In-Network Wi-Fi AP exists check box.

Step 4 Check Enable Security Alerts check box.

Step 5 In the Category pane, check one or multiple device categories for performance monitoring and alerts.

Note The default settings are Jammers and Wi-Fi ad hocs boxes checked.

When the Enable Performance Alerts and the Alert only if In-Network Wi-Fi AP Exists check boxes are checked on the Active Devices tab, and at least one In-Network Wi-Fi AP is present on the same channel as the interferer, all active interferers display with or without a security alert icon in the Active Device pane.

If the interferer duty cycle is greater than 50 percent (default critical threshold value), the device displays in red. If the total duty cycle is greater than 25 percent (default warning threshold value) but less than 50 percent, the device displays in yellow.

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Cisco WCS SNMP Trap SettingsCisco Spectrum Expert is now interoperable with Cisco WCS for:– Alerts of interfering devices

Filtering available for device type

– Transmission of spectrum dataFiltering available for channel utilization and interference

The Cisco WCS Settings window is used to enable and configure the filters and threshold levels that will trigger the sending of Cisco Spectrum Expert software data to the designated Cisco WCS IP address. The window consists of these four tabs:

Basic Settings

Filters

Security

Advanced

The Basic Settings tab has two primary functions. One function is to enable Simple Network Management Protocol (SNMP) traps or Cisco WCS functions. The other function is to identify the designated IP address of the remote computer where Cisco Spectrum Expert software data will be sent. The functions are supported by these two areas on the Basic Settings tab:

Send Spectrum Data to a Remote Computer: The Send Spectrum Data to a Remote Computer area contains two check boxes:

— A check box labeled Enable SNMP Traps for Interfering Devices, to enable the SNMP trap function

— A check box labeled Enable Cisco WCS Transmission of Spectrum Data, to enable the Cisco WCS function and the IP Address and Computer Name fields.

IP Address or Computer Name of the Remote Computer: The IP Address or Computer Name of the Remote Computer area provides IP Address and Computer Name fields to identify the target system for either the SNMP traps or Cisco WCS transmission of Cisco Spectrum Expert software data.

The Filters tab provides these four selectable channel-affecting criteria that an interferer must meet to trigger sending a trap:

Active Channel Filter: Is there an active In-Network Wi-Fi access point on at least one of the affected channels? The default state is Disabled.

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Interference Channel Utilization Filter: Does an affected channel have an interferer utilizing more than the user set channel utilization percentage? The default state is Enabled and the default threshold value is 10 percent.

Interference Power Filter: Does an affected channel have cumulative power of all interference devices at a power level within or exceeding a user-set level in decibel referenced to 1 milliwatt (dBm)? The default state is Enabled. The default value for the range is 16 dB and the exceeding default value is –70 dBm.

Interferer Type: Are there specific interferer device types that you want to include in the data sent to Cisco WCS? The type of interferer is selected from a list. Check Box, when checked, enables the scrollable list of device check boxes for inclusion in the data sent to Cisco WCS. The default setting is Disabled.

All threshold values are editable, meaning that they can be changed to reflect differing criteria.

The Security tab provides the ability to enable security measures, using certificates, for communications between Cisco Spectrum Expert software and a Cisco WCS. Several selectable security-level configurations are available to provide lower or higher security levels for the remote and local computers engaged in a Cisco WCS connection.

There are two certificate options available for a remote computer, or server, and two certificate options available for a local computer. You can define the combination of certificate criteria required in order to authorize a Cisco WCS connection. The selectable certificate-based security options are as follows:

Remote Computer Authorization for Cisco WCS Connections includes these options:

— Allow Self-Signed Certificate for Remote Server (lower security level)

— Require CA-Signed Certificate from Remote Server (higher security level)

Identifying This Computer for Cisco WCS Connections includes these options:

— Present Self-Signed Certificate for this Computer (lower security level)

— Present the Following CA-Signed Certificate for this Computer (higher security level)

There are two fields available for identifying the specific certificate authority (CA) certificate to be used if the CA-signed option is selected for either the remote or local computer.

The Action If Certificate Information Is Not Valid drop-down menu provides selectable actions to be taken upon receipt of invalid certificate information.

The Advanced tab provides an additional user-defined setting for SNMP and four user-defined Cisco WCS communication polling settings in two areas on the tab. SNMP and Cisco WCS Communication protocols function independently and can operate simultaneously. The settings are as follows:

Advanced Settings for SNMP: Displays the SNMP Trap Destination Port number. The state is dimmed, which means that the SNMP port cannot be changed.

Advanced Settings for Cisco WCS Communication: The Advanced Settings for Cisco WCS Communication provides four user-defined settings for Cisco WCS Communication parameters. The default state is Enabled and is disabled by deselecting the Enable Cisco WCS Transmission of Spectrum Data check box on the Basic Settings tab. The definable parameters are as follows:

— Transmit Devices Information Every ___ Seconds. The default value is 10 seconds.

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— Limit the Number of Device Update Records to a Maximum of ___ per Transmission. The default value is 15 per transmission.

— Consider a Cisco WCS To Be Temporarily Unavailable After ___ Unsuccessful Attempts. The default value is 10 unsuccessful connection attempts.

— Attempt Reconnection to an Unavailable Server Every ___ Minutes. The default value is 10 minutes.

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Export Data Feature

Right-click and click Export Data

The Export Data feature provides additional functionality to all Cisco Spectrum plots and charts, as well as to the devices listed in the Active Devices tree. The Export Data feature allows you to export device information to a file for future analysis. This option can be accessed by right clicking on a device name, on any plot or chart, or anywhere in the display pane to display a pop-up menu.

When Export Selected Data is selected, a window appears providing a default file name and Save In location (Spectrum Captures folder). The window also allows user selection of the file name and Save In location.

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Spectrum Plot and Chart Viewing Controls

Each plot or chart has a set of icons in the upper-right corner. Pause is very useful for stopping the display temporarily to make measurements or screen shots.Context-sensitive help is always available with the F1 key as well as the “?” icon.Any plot or chart can be zoomed to full screen either by double-clicking the header or selecting the magnifying glass icon.– Hint: This will dramatically increase the number of

sweeps available in a spectrogram display.The “X” icon allows you to close the plot or chart.

The viewing controls toolbar is found at the top right of each plot or chart, and consists of these clickable icons:

Pause (||): Used to temporarily cease or suspend activity in order to make measurements or screen shots

Help (?): Provides additional help

Magnifier: Used to zoom to full screen

X: Closes the plot or chart

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Instant ReplayFIFO buffer accessible from the recording tool panelBuffer length is configurable from 1 to 60 minutes in Tools > Settings > ConsoleConfiguration settings located at Tools > Settings > ConsoleDefault is 1 minute

The Instant Replay feature allows you to review the most recent spectrum information up to the past 60 minutes, without having to record it in a Cisco Spectrum Capture (CCF) file, and play it back as if it were being viewed live for the first time, without interrupting receipt of current spectrum information. Spectrum information viewed as an Instant Replay may then be saved as a CCF file to share information about the spectrum.

Choose Tools > Settings > Console Settings to display the Instant Replay settings options. Detailed instructions on Instant Replay Settings, Initiating an Instant Replay, and Converting an Instant Replay to a CCF file can be found in the online help.

Check the Enable Instant Replay of the Last ___ Minutes check box to enable the Instant Replay function, and enter the length of the Instant Replay (range 1 to 60 minutes).

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Spectrum RecordingDefault file name is date.time.captureStop conditions are– Manual: Stop manually– Time Elapsed: <= 1000

minutes– Size Reached: <= 512 MB

Recording size on disk: – 6 MB per hour or per band– 2.4 to 2.5 GHz +– 5.15 to 5.35 GHz +– 5.725 to 5.850 GHz = 18 MB

per hourCCF files will compress 7–8 to 1

The CCF files are subject to a size limitation of 512 MB. You should estimate CCF file size growth at a rate of 6 MB per hour or per band selected when considering the 512-MB size limitation.

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PlaybackPlay capture file does not require the Spectrum Sensor to be installed.Go Live is only operable if there is a Spectrum Sensor installed in the playback host.Local time is that of the recording Spectrum Expert Console.

You can save spectrum scans and play them back for future analysis. Detailed instructions on recording and playback can be found in the online help. The controls are as follows:

Open: Opens a previously captured CCF file for playback. You can also navigate to File > Open Capture File. Use the Open Capture File dialog box to select the recording.

Record: Opens a dialog box where you can define the name and file location of a CCF file. The recording begins automatically when you close the dialog box. You can also initiate the record operation by navigating to File > Record Capture File.

Play Capture File Once or Repeat: After you open a CCF file, select Play Capture File Once or Repeat to play to the end of the recording and stop, or play to the end and restart the playback.

Stop Record/Playback: Stops the recording process, and stops the in-progress playback of a CCF file.

Go Live: Returns you to live mode. Any playback or recording that was in progress is halted.

Pause Playback: Freezes the playback.

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Playback (Cont.) You can view capture file properties for additional information about a capture file:– Time zone– Start and end times– Sensor serial number– Monitored bands

Navigate to Help > Capture File Properties to display

The Instant Replay feature allows you to review the most recent spectrum information and play it back, as if it were being viewed live for the first time, without interruption by the current Live Capture session. Capture File Properties provides file properties information about the selected capture file.

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Indentifying Interference and Interference Sources

This topic identifies interference and interference sources using Cisco Spectrum Expert. Cisco Spectrum Expert can identify the types of devices that are producing RF interference. An interferer is any non-network RF device that broadcasts in the same frequency bands as network devices and can cause disruption to your network.


Interference Basics and DevicesTwo places to view:

Active Devices: Shows summary of current active devicesDevices tab: Provides detail and historical events

The Active Devices menu normally displays to the left of the Cisco Spectrum Expert window. In the Active Devices pane, you can see access points, ad hocs, and interfering devices, if these devices (access points and interferers) are currently live (transmitting). It uses a tree structure to organize access points, ad hocs, and different types of interfering devices.

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Active DevicesRight-click to lock device into device finderChoose What is This Device? for more detailed information:– Presents all that is known

about the device– Presents a list of known

devices that the classifier detects

To view the Active Devices menu, navigate to View > Active Devices.

If you double-click a device, a dialog box will appear that provides more detail on the device, including a picture of a typical device that matches the RF signature. (You can also right-click the device and select What Is This Device?)

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Example of Bluetooth

See hops in Max

See more hops in Max Hold

In the figure, the Real-Time FFT window shows significant energy spanning several channels.

Using the Max Hold feature allows you to view more hops. Bluetooth is a frequency-hopping protocol that covers the entire 2.4-GHz band.

Bluetooth version 2 seeks to avoid crowded channels and avoids an active Wi-Fi channel. Devices such as retail bar code scanners can be very loud. In most cases, the power can be adjusted and still meet the needs of the application with good results. In all cases, Bluetooth adds noise and reduces the SNR of the environment. Many Bluetooth devices, or one very loud Bluetooth device, will negatively impact the wireless network.

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Jammer

RF jammer, complete spectrum impacted at

–50 dBm

Constant flat signal seen in Average/Max

In this example of a jammer, the Real-Time FFT window shows a constant flat signal across several channels. Jammer devices are outlawed in the United States but are widely available on the Internet. Jammers can kill a single channel or knock out a whole band. They are excellent for denial of service (DoS) attacks.

The jammer captured in the figure is battery operated and covers 900 MHz and 2.4 GHz. It is sold on the Internet to prevent snooping or as an anti-spy device to be used to defeat listening devices and cameras. It is technically illegal, but anyone with a credit card can buy one from the Internet. The battery lasts for 45 minutes and the device is effective in a 70-meter radius.

Imagine what would happen to your network if someone dropped a jammer device into a flower planter in your lobby. The network would receive only noise in a 70-meter radius around the flower planter.

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Example of Microwave Oven

Loud moving signal as seen in Max. Drifts in

frequency

Microwave ovens definitely interfere with Wi-Fi networks. The interference is short-lived but can be very complete. In this example, the Real-Time FFT window shows significant energy centered on channels 6 and 11, but spanning several channels.

Microwaves typically impact channels 6 to 11, but mostly channel 11. This display shows interference with a wide bandwidth generated by microwaves from an older microwave oven. Newer microwave ovens tend to have narrower bandwidth. Microwave ovens are prevalent in healthcare facilities. In many cases, older microwave ovens can be damaged and emit unhealthy levels of emissions. Leakage can be caused by a broken microwave oven door, or simply by the seal being damaged or dirty.

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Cordless 2.4-GHz Phone

Channel 1 not usable due to constant signal from phone

In this example of an older cordless phone with auto-scan operation, which allows you to select different channels to avoid interference, the Real-Time FFT window in Max shows a constant signal. The manufacturer of this cordless phone wants to avoid interference, such as your network, so that the call is good. When this phone is in use, channel 1 becomes unavailable for Wi-Fi users.

It is important to educate the manufacturer of your cordless phone so that they understand the impact of the phone on your network.

Cordless phones that can cause interference to Wi-Fi are sold in the 2.4-GHz and 5-GHz bands. Best practices would be to remove these devices in a dual-band environment and replace them with cordless phones that use Digital Enhanced Cordless Telecommunications (DECT), which run in the 1.9-GHz band, or ensure that the cordless phones being used are in a different band than the Wi-Fi band.

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Example of Wireless Video Camera

Camera Off

Camera On

In this example of a wireless video camera, the Real-Time FFT window shows significant energy on channel 1. The signal is constant, therefore channel 1 is no longer usable for Wi-Fi users.

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Co-Channel and Adjacent Channel Interference

CCI comes from another access point located on the same channel, for example:– Access point next door– Neighboring cell

With Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), 802.11 devices effectively share the capacity of the channelACI comes from an access point on an overlapping channel, for example:– One access point on channel 1, another access point on

channel 2– Worse than CCI

Co-channel interference (CCI) is crosstalk from two different radio transmitters using the same frequency channel. Poor planning of frequencies can cause CCI.

Adjacent channel interference (ACI), although rare, can cause worse problems than CCI. As an example, interference is detected while surveying an arena. A spectrum analyzer feature in a wireless card helps to locate the source. The turnstiles have IEEE 802.11b radios installed in them and work wirelessly to transfer ticket information. Each door is on a separate channel. Door 1 is on channel 1, door 2 is on channel 2, door 3 is on channel 3, and so on. Whoever installed the turnstiles with the embedded Cisco Aironet radios did not understand the proper deployment design for three nonoverlapping channels (1, 6, and 11) in the 2.4-GHz band, which caused extreme ACI interference.

Wireless 802.11 WLANs use Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). CSMA/CA is a modification of pure Carrier Sense Multiple Access (CSMA). Collision avoidance is used to improve the performance of CSMA by attempting to reduce “greed” on the channel. If the channel is sensed busy before transmission, then the transmission is deferred for a “random” interval to reduce the probability of collisions on the channel.

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Setting Up Cisco Spectrum Expert This topic describes the necessary steps to set up Cisco Spectrum Expert. Before performing a Layer 1 sweep of the facility, Cisco Spectrum Expert must be configured.


Cisco Spectrum Expert Setup1. Install the Cisco Spectrum Expert

software before you install the Spectrum Expert hardware (CardBus sensor)

2. Attach the external omnidirectional antenna

3. Insert the CardBus sensor into your PC4. Start Cisco Spectrum Expert

Cisco Spectrum Expert ™

Complete the following steps to set up Cisco Spectrum Expert.

Step 1 Install Cisco Spectrum Expert software before you install the Cisco hardware (CardBus sensor).

Step 2 Attach the external omnidirectional antenna.

Step 3 Insert the CardBus sensor into your PC.

Step 4 Start Spectrum Expert.

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Cisco Spectrum Expert Setup (Cont.)

Step 6

Step 7

Step 8


Step 6 Check the Sensor Card with Internal Antenna radio button.

Step 7 Click Apply.

Step 8 Click the Band and Channel Settings icon.

Note When you perform Step 8, you will be prompted to save your settings. Save your settings.

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Cisco Spectrum Expert Setup (Cont.)

Step 9

Step 10Step 11

Step 9 Choose the appropriate Regulatory Domain from the drop-down menu and check the radio channels check boxes that you want to monitor (802.11b/g or 802.11a).

Step 10 Click Apply to save your changes.

Step 11 Click OK.

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Cisco Spectrum Expert Setup (Cont.)From the Cisco Spectrum menu, choose your views.Choices:– Real Time FFT– FFT Duty Cycle– Swept

Spectrogram– Interference

Power

Step 12

Step 12 From the Cisco Spectrum menu, choose your views. The choices shown include the following:

Interference Power

Real Time FFT

Swept Spectrum

FFT Duty Cycle

The following views are available for selection:

Plots:

— Real Time FFT

— FFT Duty Cycle

— Swept Spectrum

— Power vs. Frequency

— Power vs. Time

Charts:

— Active Devices

— Devices vs. Channel

— Devices vs. Time

— Channel Utilization

— Channel Utilization vs. Time

— Interference Power

— SNR

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Devices

By selecting the Devices tab, you can see all detected devices.

To see Wi-Fi devices, you must have a Wi-Fi card running in passive mode.

An 802.11 a/b/g/n internal PCI card is recommended.

The Devices view shows detailed statistics for each device, including currently active and historical devices. Devices listed here include network devices and interferers. You can access this view by selecting the Devices tab. The data in the Devices view is organized in tabular form. The following list of fields is provisional and subject to change:

Device Name: The name of the interfering device.

Network ID: Network address for this device, if available (for example, the Basic Service Set Identifier [BSSID] for an 802.11 device, or the piconet address for Bluetooth devices).

Device ID: The device address for the device, if available. Examples would be the MAC address for 802.11 access points, the device address for Bluetooth devices, and so on.

Discovery Time: When the device was first detected.

On Time: Amount of time that the device has been on since it was detected.

Channels Affected: Channels affected by transmissions from this device.

Duty Cycle: Measured duty cycle for this device.

Signal Strength: Average received signal strength (log average) for pulses from the device.

Avg Pulse Duration: Average pulse duration for pulses received from this device.

Details: Miscellaneous device-dependent details are reported here. For example, for 802.11 access points, such details may include Wired Equivalent Privacy (WEP) information, supported rates, protocols, and so on.

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Collect Data

The primary goal of the site survey is to determine which channels or bands are acceptable for network deployment. The survey can also suggest the number of network devices that may need to be purchased and deployed. This is particularly crucial for those networks, such as Wi-Fi networks, in which you have a choice of the type of network equipment to purchase (802.11a, 802.11b, or 802.11g).

The site survey entails physically moving your PC with Cisco Spectrum Expert software throughout the network space, monitoring changes in the readings as you go. You should walk around the perimeter of each office, and perhaps up and down and side-to-side through the center of each office. In a hallway or corridor, it may be sufficient to roll the laptop down the center of the hallway.

The more fine-grained your site survey, the more accurate the information you will obtain. Taking measurements in four corners of a large space, and at the center of that same space, is generally not sufficient.

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Locate Interferers The Devices view shows detailed statistics for each device, including currently active and historical devices. This topic shows you how to locate interference sources using Cisco Spectrum Expert.


Locating Devices with Device Finder

An increase in signal strength is an indication that you are moving closer to the device.

The black box around one of the bars on the meter indicates the strongest signal that has been detected.

To use the Device Finder, complete these steps:

Step 1 In Devices view, or on the Active Devices menu, select the device you wish to locate. Then right-click the device name and click Find This Device on the pop-up menu.

Step 2 The device is now listed in the Device Finder.

Step 3 The Signal Strength History graph shows a moving plot of the signal strength. (The plot does not automatically reset if the signal is lost.) This plot makes it easy to visualize when you are walking towards or walking away from the source of the signal. The Rx Signal Strength meter provides a real-time indicator of the signal strength from a device and is an additional tool in determining whether you are “getting warmer” or “getting colder” in terms of tracking down the interfering device. At moments, you will record a signal of special interest; the signal may suddenly peak or drop off, or you may be systematically recording the signal at carefully planned locations.

Step 4 To maintain a record of the signal of interest, click Record Signal, or press the Spacebar. Cisco Spectrum Expert records the current signal strength and the time in the Measurement Log. For a description, Spectrum Expert uses the device name as a default value.

Step 5 Type in a description of where the measurement was taken. Click Enter to confirm your description.

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Step 6 You can also edit the location information in the Measurement Log at a later time. Simply double-click the description and then key in your new description; then click Enter. Press Esc to cancel any changes you are making.

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Additional Device Finder Features

The Device Finder has these additional features and capabilities:

Stop Finding: You can stop tracking the interferer by clicking Stop Finding. You should do this after you have found the interferer, to reduce the drain on system processing resources.

Reset Signal Averaging: If you click Reset Signal Averaging, Spectrum Expert no longer uses prior signal values to calculate the average signal strength. Instead, Spectrum Expert only calculates average signal strength from that point on. If you are moving around, or changing the orientation of a directional antenna, this command will cause the signal averaging measurement to restart, so you will not display data that may be representative of the prior position or orientation. Filtering is applied to provide accurate measurements, which can help Cisco Spectrum Expert to respond more quickly and not be biased from prior measurements.

Clear Signal Strength History: Click Clear over the receive (Rx) Signal Strength History plot to clear the plot.

Clear Measurement Log: You can clear the Measurement Log of all data by clicking Clear Log above the log.

Delete A Single Log Entry: You can also delete an individual row from the Measurement Log. Simply select the entry, and then press the Del key on your keyboard. Then click Yes in the confirmation dialog box.

Reset Maximum Signal Strength: If you click Reset Max, Cisco Spectrum Expert deletes the current value for the maximum signal strength. Cisco Spectrum Expert then determines the maximum interferer signal strength measured from that time.

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Divide-and-Conquer Search Strategy

To minimize your effort and maximize your chances of locating the interferer, you should use a divide-and-conquer search strategy (also known as rectangular bisection). The figures illustrate the strategy, first with the omnidirectional antenna, and then using the directional antenna. To use this process, you will greatly benefit from using a physical map of your network space.

Note It is possible to hit a blind spot when using Device Finder. In such a location, typically a corner in a large building, you may not get any measurements. If you spend more than 30 seconds at one spot without getting an updated device reading, you should move away from that spot and try a different location.

Follow these steps to use the divide-and-conquer search strategy:

Step 1 Go to each of the four corners of the office space and measure the signal strength from the interfering device of interest. Take note of which corner of the office yields the highest signal strength. (A printed map of your office space can be helpful for jotting down data.)

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Reset Signal Averaging

Step 2 Each time you move the Spectrum Expert system to a new location, click Reset Signal Averaging on the Device Finder. Then, at each test location, wait for the confidence level to settle to a small value, ideally less than ±3 dBm, but certainly less than ±5 dBm, before recording the signal strength.

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Repeat the Process

Step 3 In the corner which has the largest signal strength, map out a rectangular sub-search area comprising one quarter of the total office space.


Repeat the Process (Cont.)

Step 4 Repeat this process as necessary to localize your measurement.

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Final Stage

Step 5 By repeating this process, you will be able to home in on the location of the interfering device.

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Directional Antenna

The advantage of using the directional antenna is that you can save yourself a substantial amount of walking, because four measurements at a time can be made from one central location. Follow these steps to use the directional antenna in the divide-and-conquer search strategy:

Step 1 Once again, assuming a rectangular office space, take your Spectrum Expert PC to the center of the office space. Use the directional antenna, with Device Finder, to determine the signal strength coming from your interferer, as measured in each of four directions. For each measurement, the antenna should be pointed towards each of the four corners of the office.

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Repeat the Process

Step 2 Once again, for the corner that has the largest signal strength, map out a rectangular sub-search area comprising one quarter of the total office space. Again, you only need to make measurements from one spot, pointing the antenna in four different directions.


Repeat the Process (Cont.)

Step 3 Repeat, again making measurements in the quadrant with the highest power reading.

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Final Stage

Step 4 Once again, you will learn from experience whether the final measurements are best made by a continued process of rectangular bisection, or whether the final measurements should be made on a systematic grid of a local area.

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SummaryCisco Spectrum Expert can identify interference by non-Wi-Fi devices in the 2.4- and 5-GHz spectrum.0 dBm is equal to 1 mW.Cisco Spectrum Expert software analyzes data from the sensor card and provides a GUI-based view of the network and RF activity.There are five FFT plots and seven charts to choose from, with a Devices page to analyze interference issues. Cisco Spectrum Expert can identify non-802.11 devices such as cordless phones and microwave ovens.The Device Finder feature in Cisco Spectrum Expert helps physically locate interfering devices.An omnidirectional antenna and a directional antenna are available for use with the Cisco Spectrum Expert sensor card.

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Lesson 3

Conducting a Layer 2 Site Survey for Data

Overview A site survey for data applications should be based on the average and peak number of users that will use the WLAN. The accepted throughput per user and the coverage is seamless. With IEEE 802.11n technology, data rates of up to 300 Mb/s can be generated across the WLAN. Newer data-only WLANs with 802.11n clients and Cisco Aironet 1250AG Series or Cisco Aironet 1140 Series Access Points can take full advantage of the higher speeds that can be built into a WLAN.

Objectives Upon completing this lesson, you will be able to conduct a Layer 2 site survey for data applications using AirMagnet Survey PRO. This ability includes being able to meet these objectives:

Describe signal attenuation as the signal passes through different objects

Identify site survey best practices for a data site survey

Describe how to create a data site survey with AirMagnet Survey PRO

Describe how to configure AirMagnet Survey PRO

Describe how to conduct a data site survey with AirMagnet Survey PRO

Describe how to merge and display data collected during the active and passive survey

Describe how to generate reports using the reports feature in AirMagnet Survey PRO

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Attenuation Characteristics of Building Materials This topic describes signal attenuation as the signal passes through different objects. Signal attenuation or signal loss occurs even as the signal passes through air. The loss of signal strength is more pronounced as the signal passes through different objects.


Signal Attenuation

There is no way of determining the distance that an RF signal will travel without conducting a survey.

Object in Signal Path Signal Attenuation Through ObjectPlasterboard wall 3 dB

Glass wall with metal frame 6 dBCinderblock wall 4 dBOffice window 3 dB

Metal door 6 dB

Metal door in brick wall 12 dB

Human body 3 dB

Signal attenuation or signal loss occurs even as the signal passes through air. The loss of signal strength is more pronounced as the signal passes through different objects. A transmit power of 20 mW is equivalent to 13 dBm. If the transmitted power at the entry point of a plasterboard wall is at 13 dBm, the signal strength will be reduced to 10 dBm when exiting that wall. The table in the figure shows the likely loss in signal strength caused by various types of objects.

Each site surveyed will have different levels of multipath distortion, signal loss, and signal noise. Hospitals are typically the most challenging environment to survey due to high multipath distortion, signal loss, and signal noise. Hospitals take longer to survey, require a denser population of access points, and require higher performance standards. Manufacturing and shop floors are the next hardest to survey. These sites generally have metal siding and many metal objects on the floor, resulting in reflected signals that re-create multipath distortion. Office buildings and hospitality sites generally have high signal attenuation but a lesser degree of multipath distortion.

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Construction Methods and MaterialsExamples of materials that affect RF coverage:– Metal film on glass– Leaded glass– Steel-studded walls– Cement floors and walls with steel reinforcement – Foil-backed insulation– Stairwells and elevator shafts– Plumbing pipes and fixtures– Air conditioning and heating ducts

Many aspects of building construction are unknown or hidden from the site survey, so you might have to acquire that information from other sources, such as architectural drawings. Some examples of typical construction methods and materials that affect the range and coverage area of access points include metal film on glass, leaded glass, steel-studded walls, cement floors, walls with steel reinforcement, foil-backed insulation, stairwells, elevator shafts, plumbing pipes and fixtures, and many others.

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InventoryVarious types of inventory can affect RF range, such as these examples:– Printer paper– Cardboard boxes– Pet food– Paint– Petroleum products– Engine parts

Levels of inventory– A warehouse with 50 percent of inventory has a very different

RF footprint than a warehouse at 100 percent of inventory.

Different types of inventory affect RF range, particularly inventory with high steel or water content. Printer paper, cardboard boxes, pet food, paint, petroleum products, and engine parts are just a few examples.

It is important that the engineer perform the site survey at peak inventory levels or at times of highest activity. A warehouse at 50 percent stocking level has a different RF footprint than the same warehouse at 100 percent.

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Activity LevelConduct survey during peak density of users.If this is not possible, be sure to tweak installation as needed during peak user density.Additional signals from users cause more contention, more null points.Multipath, while good for 802.11n, is not good for 802.11 Direct Sequence Spread Spectrum (DSSS) users.Use diversity antennas.

An office area at night (without people) will have a different RF footprint than the same area full of people during the day. Although many parts of the site survey can be conducted without full occupation of the area, it is essential to conduct the site survey verification and tweak key values during a time when the location is occupied.

The higher the utilization requirements and the higher the density of users, the more important it is to have a well-designed diversity solution. When more users are present, more signals are received on each user device. Additional signals cause more contention, more null points, and more multipath distortion. Diversity on the access point helps to minimize these conditions.

802.11n multiple-input, multiple-output (MIMO) technology makes use of multipath by combining information from all signals received, thereby increasing throughput. This is known as maximal ratio combining (MRC), where multiple received signals are combined to more accurately reconstruct the transmitted signal.

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Multifloor BuildingsKeep in mind the following guidelines when conducting a site survey for a typical office building: – Elevator shafts block and reflect RF signals.– Supply rooms with inventory absorb RF signals.– Interior offices with hard walls absorb RF signals.– Break rooms (kitchens) may produce 2.4-GHz interference

through the use of microwave ovens.– Test labs may produce 2.4- or 5-GHz interference, creating

multipath distortion and RF shadows.– Cubicles tend to absorb and block signals.– Conference rooms have high-utilization requirements and

require a greater number of access points.

Keep in mind the following guidelines when conducting a site survey for a typical office building:

Elevator shafts block and reflect RF signals.

Supply rooms with inventory absorb RF signals.

Interior offices with hard walls absorb RF signals.

Break rooms (kitchens) may produce 2.4-GHz interference through the use of microwave ovens.

Test labs may produce 2.4- or 5-GHz interference and create multipath distortion and RF shadows.

Cubicles absorb and block signals.

Conference rooms have high-utilization requirements and require a greater number of access points.

Take extra care when surveying multifloor facilities. Access points on different floors can interfere with each other as easily as access points located on the same floor. It is possible to use this behavior to your advantage during a survey. A high-gain antenna placed near a ceiling in a multifloor facility can easily provide coverage to the floor above as well as to the floor below. Be careful not to overlap channels between access points on different floors or access points on the same floor.

In multi-tenant buildings, there might be security concerns that require the use of lower transmission powers and lower-gain antennas to keep signals out of neighboring rooms or offices.

If auto-Radio Resource Management (RRM) is used for a data-only WLAN, you should survey at half power or less to ensure that the RRM can perform coverage hole mitigation.

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Best Practices for a Data Site Survey This topic identifies best practices for a data site survey. Data-only deployments do not require a large amount of overlap because 802.11 clients respond to a lower signal from a nearby access point by stepping down their rate and taking a longer time to transmit.


Best Practices for a Data-Only Site Survey

For 802.11a/b/g/n networks.Identify clients to be supported on 802.11a/b/g/n networks.If there are no 802.11 clients, turn off 1- and 2-Mb/s data rates.If there are no 802.11b clients, turn off all 802.11b data rates.If there are 802.11b clients, turn off data rates of 1, 2, 5.5, 6, and 9 Mb/s.Reduce output power to 25 mW maximum on the access point.Ensure that clients use DTPC.

Clients learn the data rates that are configured on the access point during the association process to the access points. It is expected that once a client is associated to an access point, it will only use the rates enabled on the access point. This is good news because it gives you, as the designer, the ability to control this factor. For example, a cell that has both an 802.11b Direct Sequence Spread Spectrum (DSSS) and 802.11g (orthogonal frequency-division multiplexing [OFDM]) support requirement may have a maximum cell throughput of 13 Mb/s. A cell that is only 802.11g OFDM or 802.11a OFDM may have a maximum cell throughput of 25 Mb/s.

In dense client deployments, the data rates configured on the access point must be managed for best RF channel efficiencies. If the 802.11 data rates of 1, 2, 5.5, and 11 Mb/s are not needed for client support, those rates should be disabled. If there is a need to support 802.11b, then enable only 11 Mb/s. For an 802.11g/a high-density design, it is recommended that you set 12 Mb/s as the minimum data rate. The lowest configured required rate is the rate that beacons will be sent. Clients will tend to gravitate over time to this rate as well. The slower the data rate, the higher the channel usage will be. Slower rates require more time in the channel to transmit.

You should reduce the power during the survey to a maximum of 20 mW to ensure that RRM works properly once it is deployed.

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Dynamic Transmit Power Control (DTPC) is a configuration option on the autonomous access points and is standardized on the lightweight access points. The purpose of DTPC is to balance the transmit power of a client radio with the transmit power of an access point to which the client is associated. The DTPC is used to inform a client radio of a suggested transmit power level. Both the 2.4- and 5-GHz radios of the access point advertise a transmit power value in the 802.11 beacon and probe responses. Generally, the advertised transmit power is the current transmit power of the access point radio.

Most current laptops have radio technology that automatically takes advantage of DTPC. It is a recommended best practice to have DTPC as a requirement on the client side. By instructing the client what power level to use, you maximize the connection while minimizing the co-interference potential and maximize the battery life of portable client devices. There is no good reason to have a client transmit at 30 mW when the access point is transmitting at 5 mW. In an environment where there are a high number of client devices in a small coverage area, high transmit powers work against channel efficiencies. Higher power increases the collision domain of channels. Increasing the collision domain increases co-channel interference and decreases channel efficiency.

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Best Practices for a Data-Only Site Survey (Cont.)

Use nonoverlapping channels, three available for 2.4-GHz and 23 available in the 5-GHz spectrum.High-density data deployments should use the 5-GHz spectrum due to increased channels available.10 to 15 percent cell overlap.

Aggregate channel capacity is the relative amount of floor space versus the number of users to be covered. The more channels that you can plan within a small area, the better the results will be.

For instance, the 2.4-GHz spectrum has only three nonoverlapping channels (1, 6, and 11). If those three channels need to support 802.11b and 802.11g clients in a channel shared floor space, the aggregated channel bandwidth would be no more that 39 Mb/s. That is, 13 Mb/s for each of the three channels. Putting six access points (two on each of the three channels) in the same shared floor space would not double the aggregated bandwidth in the floor space. In fact, it may reduce the total throughput in the floor space because of co-channel interference. There are some advantages to having more than one access point on a channel, for instance, the clients can load-balance between access points. Also, in a highly utilized channel, there will be much backoff time due to channel busies. The added access points provide extra packet buffering and reduce the overall number of packet retries, which will increase the channel utilization further and make the problem worse. If you are adding access points that can hear each other in a channel, you will need to carefully manage co-channel interference using other aspects of the design, such as overall cell size and overlap.

Using 5 GHz in a dense deployment is highly advisable. The advantages to this are a higher channel throughput with 23 channels available. An auditorium could use one access point for each 802.11a/n channel without having to do a managed design around co-channel interference. Using 5 GHz in the auditorium could have 325 Mb/s of throughput.

Any energy in the WLAN spectrum that is not decodable as an 802.11 radio is considered noise. The ambient noise floor will differ on every site but will always be present. Electrical components have an internal noise, known as thermal noise, that will be present even in a quiet RF environment. The signal-to-noise ratio (SNR) is the ratio (actually the delta) of signal (802.11 radio) to noise (anything that is not an 802.11 radio signal). The SNR is expressed as a value in decibels (dB).

The lower the SNR in an environment, the slower the resulting supportable data rate will be.

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The noise level affects the ability of a Wi-Fi radio to hear and decode the signal. Wi-Fi radios are rated for sensitivity (a value in dBm), which is the minimum amount of signal required for reliable operation at a given data rate. Lower data rates are more tolerant to noise and require less SNR, but there is a tradeoff. The lower data rates also reduce the efficiency of the entire WLAN. In order for an 802.11 WLAN to operate, there needs to be a margin of clean spectrum between the energy level of the ambient noise floor and the received signal levels.

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Cell Coverage Limitations: Parameters to Watch

Minimum SNR– Provides a level of good signal over noise floor

Minimum signal strength– Watch for:

Consistent valuesMinimum valuesRapid fluctuations (indicates multipath distortion)

Noise floor– Higher noise floor will affect minimum signal strength

Packet counts, lost packetsUse packet sizes similar to those for the applications that have the largest packet size.

When performing the survey, you must set parameters and thresholds to identify where the cell edge should be placed. In order to do this correctly, you must watch several key items.

Many surveys use only signal strength, but using this alone is not enough. You should also watch the noise floor and the ratio between the signal and noise. Also, when possible, you should watch packet transfer performance (packet count) or ping times for packets moving between access points and clients.

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Received Signal Strength IndicationBest indicator of wireless performanceCan be measured by various devices– Cisco Aironet Site Survey Utility– AirMagnet Survey or AirMagnet Survey PRO – Client utilities

Measured in dBm– Usable range typically from –60 to –80 dBm

–55 dBm or greater is exceptional signal strength–85 dBm is poor signal strength and association is unlikely-–65 dBm for highest data rate supported (recommended)

Received Signal Strength Indicator (RSSI) is the best indicator for wireless performance.

RSSI can be measured by various devices including:

Cisco Aironet Site Survey Utility

AirMagnet Survey or AirMagnet Survey PRO

Client utilities

RSSI is measured in dBm. The usable range is typically from -60 to -80 dBm.

Anything greater than –55 dBm is considered exceptional signal strength; anything less than –85 dBm is poor signal strength and association is unlikely. The recommended range for the highest data rate supported is –65 dBm.

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Recommended Parameters for 2.4-GHz Data Networks

Minimum packet performance should be greater than 90 percent successful packet transfer (10 percent packet error rate [PER]).

Data Rate Rx Threshold Recommended Minimum Rx Threshold

Rx Signal-to-Noise Ratio

Recommended Minimum Signal-to-Noise Ratio

54 -71 -61 25 35

48 -72 -62 22 31

36 -73 -63 18 28

24 -77 -67 12 22

12/11 -82 -72 10 20

6/5.5 -89 -79 8 18

2 -91 -81 6 16

1 -94 -84 4 14

The table in the figure indicates specifications for the Cisco Aironet 802.11g radio parameters. The Cisco Aironet 802.11b radio specifications at data rates of 1, 2, 5.5 , and 11 Mb/s are nearly identical to the 802.11g radio, so either radio may be used when surveying at 802.11b data rates.

The values vary for different data rates, and the data rate at which the engineer is surveying needs to be noted for minimum performance.

The minimum receive (Rx) threshold indicates the absolute minimum that the receiver can hear and still properly decode the packet. This value needs padding to compensate for variations in transmitters, receivers, and environment. A typical padding of 10 dB is sufficient. The recommended minimum Rx threshold indicates the value that you should watch for to indicate the edge of reliable coverage.

The SNR rating indicates the minimum ratio between the noise floor and the desired signal level for proper reception of information.

The recommended SNR value provides a 10-dB padding to compensate for variations. Both values should be monitored for minimum values. As the noise floor changes, this change can affect the minimum signal strength that is needed. At the same time, the packet performance should be monitored to provide a minimum of 90 percent successful packet transfer.

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Data Rate Rx Threshold Rx Signal-to-Noise Ratio

144.4 -64 29

130.0 -65 28

115.6 -66 27

86.7 -70 23

57.8 -74 19

43.3 -77 16

28.9 -79 14

14.4 -82 11

Recommended Parameters for 2.4-GHz 802.11n Data Networks, Channel Width 20 MHz

Minimum packet performance should be greater than 90 percent successful packet transfer (10 percent PER).

In the figure, the 802.11n data rate and Rx threshold s were obtained from AirMagnet Survey PRO. The 20-MHz chart can be used for 2.4 GHz or 5 GHz.

The 2.4-GHz, 40-MHz channel is not recommended because there are only three nonoverlapping channels.

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Recommended Parameters for 5-GHz Data Networks


Data Rate Rx Threshold Recommended Minimum Rx Threshold

Rx Signal-to-Noise Ratio

Recommended Minimum Signal-to-Noise Ratio

54 -68 -58 20 30

48 -71 -61 17 27

36 -73 -63 14 24

24 -77 -67 12 22

12 -82 -72 7 17

6 -85 -75 5 15

The method of measuring the cell edges at 5 GHz is very similar to the 2.4-GHz recommendations. The values will vary slightly and the receivers are different.

Similarly to 2.4-GHz data networks, 10-dB padding is also included.

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Recommended Parameters for 5-GHz 802.11n, Channel Width 40 MHz

Data Rate Rx Threshold Rx Signal-to-Noise Ratio

300.0 -61 32

270.0 -62 31

240.0 -63 30

180.0 -67 26

120.0 -71 22

90.0 -74 19

60.0 -76 17

30.0 -79 14


In the figure, the 802.11n data rate and Rx threshold s were obtained from AirMagnet Survey PRO. The 40-MHz chart can be used for 2.4 GHz or 5 GHz.

The 2.4-GHz, 40-MHz channel is not recommended or supported by Cisco because there are only three nonoverlapping channels.

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Create a Data Site Survey Project This topic describes how to create a data site survey with AirMagnet Survey PRO. To create an indoor site survey project, import a site map and specify some physical properties of the site.


Survey Screen UI ComponentsMap

Window

Project Window

Data Window

Media Type

Menu Bar

Tool Bar

Refresh

Legend

Navigation Bar

To launch AirMagnet Survey PRO, navigate to Start > All Programs > AirMagnet Survey > Survey. When prompted to load a prepared image to learn how to use Survey, click Yes or No.

The Survey user interface components include the following:

Project Window: Shows the components of the current project in separate folders. Its contents vary, depending on the screen selected. The options apply only to the Survey, Display, and MultiFloor screens.

Data Window: Provides controls for performing site surveys or data analyses. The Survey screen shows real-time RF data as it is captured during a survey; the Display screen shows the channel and Service Set Identifier (SSID) structure of the RF environment based on collected data and an overview of the site map.

Map Window: Displays the floor map of the current project, along with data you choose to display.

Navigation Bar: Allows you to navigate to different screens of the application.

Menu Bar: Contains three menu groups: File, View, and Help. The content of the File and View menus varies, depending on the screen that you choose.

Toolbar: Contains all the tools that AirMagnet Survey offers. The tools on the Toolbar vary, depending on the screen that you choose.

Legend: Allows you to use various color schemes or patterns to tailor the graphical display and analysis of survey results.

Media Type: This button is available only on the Survey and Display screens.

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Survey screen: Allows you to choose the media type (for example, 802.11 a/b/g, FCC 4.9, promiscuous mode) by which data will be collected.

Display screen: Reflects the media type of the data displayed on the screen.

Refresh button: Allows you to update the data display on the screen .

The Navigation Bar

The navigation bar serves as a launching pad for the various screens and utilities that AirMagnet Survey offers. It allows you to navigate through the major user interfaces of the program when you click the button. However, the options on the navigation bar vary, depending on the version of the software (PRO versus Standard). The figure shows the Survey PRO navigation bar, which includes these utilities:

Planner: Opens AirMagnet Planner, which allows you to diagram your site before deployment in order to determine optimal base station configuration.

Survey: Opens the Survey screen, which allows you to perform site surveys to collect RF data on a WLAN site. By default, AirMagnet Survey opens in the Survey screen.

Display: Opens the Display screen, where you can view and analyze RF data collected during site surveys.

Simulation: Allows you to conduct data simulation on signal coverage.

AirWISE: Allows you to access advice on access point deployment based on RF data collected during site surveys.

Multi View: Allows you to display and analyze RF data collected from sites with multiple floors so that you can visualize the interrelationship among the access points across the floors.

Reports: Opens the Reports screen, which allows you to generate reports based on the selected survey data.

Tools: Opens the Tools screen, which allows you to perform some basic troubleshooting using the built-in active tools.

Calculator: Opens the Calculator screen, which allows you to calculate various parameters crucial for WLAN deployment.

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New Project WizardEnter:

Project NameProject Directory

Click Next

To create a new Survey project for an indoor site survey, follow these steps:

Step 1 From the toolbar, select the Project Wizard icon or from the Main Menu, navigate to File > New Project.

Step 2 In the Specify Project Name text box, enter a unique name for the new project.

Step 3 To save the project to the default location, click Next. The New Project Wizard screen refreshes.

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New Project Wizard (Cont.)Import floor plan imageIf known, enter floor plan dimensions If not known, use the calibration tool later (recommended)Click Next

Step 4 Click Import Indoor Floor Plan Image to locate and import the site map of the location where surveys will be conducted.

Step 5 For Unit of Measurement, choose Feet or Meters in the drop-down menu.

Step 6 For Floor Plan Dimensions, enter the width and length of the site map.

Note Dimension refers to the entire area covered by the site map. It may or may not be the same as the dimension of the facility that resides on the site. If you are not sure of the exact width or length, you may enter the approximate values and then let AirMagnet Survey recalibrate the values for you later.

Step 7 Click Next. The New Project Wizard screen refreshes.

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New Project Wizard (Cont.)Select your survey environmentEnter your Signal propagation assessment (default recommended)Enter AP default powerClick Next

Step 8 For Survey Environment, enable an option that resembles the site environment where the survey is to be conducted.

Step 9 For Signal Propagation Assessment, do nothing (normally), because AirMagnet Survey can automatically assign the value according to the site environment that you choose.

Note AirMagnet Survey assigns the Signal Propagation Assessment value based on the estimate of the distance that RF signals could travel in each of these typical site environments. Normally, it is recommended that the user accept the default value that the program assigns. However, if you want to set a value of your own, you should be aware that the value you enter will affect the way the program interpolates site data.

Step 10 For AP Default Power, do nothing (normally).

Note If you know the value of the access point power, enter it now. The value will be used when conducting data simulation.

Step 11 Click Next. The New Project Wizard screen refreshes.

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New Project Wizard (Cont.)Enter any descriptive textClick Finish

Step 12 In the Enter Descriptive Text field, type a brief description of the project. This field is optional.

Step 13 Click Finish. The newly created Survey project will automatically appear in the project window, and the site map will be displayed in the map window.

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Project Created

You can create as many projects as needed by following the same procedure. By default, a new project will automatically open on the Survey screen as soon as it is created.


Recalibrate MapSelect the calibration toolTake a known measurement of the floor. Click RecalibrateClick OK

To calibrate the floor plan, use a measuring wheel to measure the distance in one of the rooms. Then using the Calibration Tool, you can calibrate your floor plan. This will calibrate the floor plan to the actual size if it was unknown before.

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Survey Screen UI ComponentsMap

Window

Project Window

Data Window

Media Type

Menu Bar

Tool Bar

Refresh

Legend

Navigation Bar

The Survey screen is used for conducting WLAN site surveys, which are used for collecting RF data in the airwaves over the site. After a Survey project is created, it will be automatically opened on the Display screen. The same thing happens when you open a Survey project that you have created earlier.

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Select Media

802.11a

80211g802.11agFCC 4.9

On the top of the Survey screen is the media type button, which shows a drop-down menu when you mouse over it. It allows you to choose the media type by which the data are transmitted in the airwaves. It offers the following options:

802.11a: Selecting 802.11a allows the wireless network card to scan data from 802.11a access points only. 802.11a access points use RF channels 36 and above.

802.11g: Selecting 802.11g allows the wireless network card to scan data from 802.11b/g access points. 802.11g access points use RF channels 1 through 14.

802.11a/g: Selecting 802.11a/g allows the wireless network card to scan data from 802.11a/b/g access points.

4.9 GHz: The FCC 4.9-GHz band is solely used for US Public Safety. This mode will only work with a TRENDnet wireless adapter.

A/P Mode: Associated promiscuous mode works only with supported Intel wireless cards. This mode allows your network card to recognize all network traffic that it comes in contact with.

Note Although AirMagnet Survey supports all these Wi-Fi standards, it is highly recommended that you choose a media type before you start on a site survey. This will enable you to concentrate your individual surveys on access points using a specific type of media.

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Survey Screen File Menu

After the media type is chosen, you need to choose one of the following from the Survey screen File menu:

New Project: Opens the New Project Wizard window, where you can create a new Survey project. It works in the same way as Project Wizard on the toolbar.

Open: Opens an existing Survey project. It works in the same way as Open Project on the toolbar.

Save: Saves changes made to the current project. It works in the same way as Save on the toolbar.

Close Project: Closes the current project.

Configure: Opens the Survey Configuration dialog box, where you can configure the following parameters on AirMagnet Survey: Settings, Color, 802.11, Scan, MapPoint.

Print: Opens the Print dialog box, where you can print the current project.

Print Preview: Allows you to preview what is going to be printed.

Print Setup: Opens the Print Setup dialog box, where you can choose paper options.

Recent Projects: This section lists the most recently opened Survey projects.

Exit: Allows you to exit from AirMagnet Survey.

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Survey Screen View Menu

The Survey screen View file menu includes the following options:

Zoom In: Enlarges the view of the current floor map in the map window. It works in the same way as Zoom In on the toolbar.

Zoom Out: Reduces the view of current floor map in the map window. It works in the same way as Zoom Out on the toolbar.

Zoom to Fit: Fits the current floor map to the map window. It works in the way as Zoom Fit on the toolbar.

Zoom to Actual Size: Fits the current floor map to its actual print scale. It works in the same way as Zoom to Actual Size on the toolbar.

Set Zoom: Opens the Set Zoom dialog box, where you can specify the specific ratio at which the view of the map can be increased.

Project Properties: Opens the Project Properties window, where you can adjust the physical properties of the floor map of the survey site.

AP/Path Name Font: Opens the Font window, where you can modify the font properties of APs and survey paths on the floor map.

Show Rules: Allows you to show or hide the rulers along the edge of the map window.

Show Grids: Allows you to show or hide grids in the map window.

Show Toolbar: Allows you to show or hide the Toolbar.

Show Legend: Allows you to show or hide the Legend.

Copy: Allows you to copy what is in the map window and paste it into any application that supports copy-and-paste.

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Survey Screen Toolbar

Project Wizard

Open Project

Configuration

Start Survey

Pause Survey

Zoom In

Zoom Fit

GPS or Manual Mode

Save

Measure Mode

Stop

Retract

Zoom Out

Survey Zoom

The Survey screen toolbar includes the following options:

Project Wizard: Opens the New Project Wizard, where you can create a new Survey project.

Open Project: Opens an existing Survey (.svp) file.

Configuration: Opens the Survey Configuration window.

GPS or Manual Mode: Allows you to switch between GPS-aided survey and regular survey.

Save: Saves changes that you have made.

Measure Mode: Allows you to recalibrate site dimensions to suit your location.

Start Survey: Starts a new survey.

Stop Survey: Ends the current survey.

Pause: Stops the survey momentarily.

Retract: Erases unwanted survey paths for the current survey, one step backward at each click. Choosing another data point on the site map will resume the survey.

Zoom In: Enlarges the view of the site map.

Zoom Out: Reduces the view of the site map.

Zoom Fit: Fits the site map to the Map window.

Survey Zoom: Covers the screen with the Map window.

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Survey Screen Project WindowDisplays the following:

Site mapActive survey pathsPassive survey pathsAccess points

The Project window displays all the components of the current projects. Its contents vary slightly depending on the screen option that is being used.

The Survey screen Project window contains the following components:

Site Map: Contains all the site maps for the Survey project. To choose a site map, put a check mark in the check box in front of the map file. The selected map will be displayed in the Map window. By default, a site map is automatically selected and displayed when a new project is created, or when an existing project is opened.

Survey Path: Contains all the survey paths recorded during a site survey. You can have as many survey paths in the folder as you recorded, and you can display as many of them as necessary. To display a survey path, check the check box in front of the survey path file.

AP: Contains all the access points against which active surveys are conducted. You can have as many access points as recorded and display as many of them as necessary. To display an access point, put a check mark in the check box in front of the access point file.

Note By right-clicking on the Survey screen Project window, you can delete or check or uncheck all.

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Active Survey Screen Data Window

Active or Passive (Selectable)

AP or SSID (Selectable)

AssociatedAP Status

Signal, Noise,and Signal-to-Noise Display

AP Name or MAC Address (Selectable)

Packet Status

Packet Size (Selectable)Delay in ms (Selectable)

The Active Survey data window includes the following parameters:

Basic Service Set Identifier (BSSID): The name and MAC address of the associated access point

SSID: The name of the network to which the associated access point belongs

Speed: The rates (Mb/s) at which packets are transmitted

Channel: The radio channel that the access point uses to send and receive RF signals

Signal: The signal strength for the received packets; the higher the value, the stronger the signal

Noise: The level of background radio frequency energy in the 2.4- or 5-GHz band; the lower the value, the less the noise

S/N: The signal-to-noise ratio; compares the signal data to the amount of ambient noise

Packet Size: The size of the packet transmitted in bytes

Delay: The delay in milliseconds between successive transmissions

Roaming Option: Allows you to set the roaming criteria for the survey

Bytes: The number of bytes (of data) transmitted per second

Packets/s: The number of packets (of data) transmitted per second

Lost: The percentage and number of packets that were not transmitted successfully from the access point

Retry: The percentage and number of packets that were resent if an acknowledgment (ACK) was not returned by the access point

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Passive Survey Data WindowThe Survey data window in passive mode displays the following:

ChannelMAC address or name of access pointSignal strengthNoiseSNRSSID (if known)Current access point countMax displayed access points

The passive Survey data window includes the following parameters:

Channel: The RF channel all access points are using as captured by the wireless network card

MAC Address: The MAC addresses of all the access points

Signal Strength: The signal strength of all received packets

Noise Level: The level of background RF energy in the 2.4- or 5-GHz band; the lower the value, the less the noise

Signal/Noise Ratio: The difference between signal strength and noise level

SSID: The name of the network to which an access point belongs

Current AP Count: The number of access points detected

Max Displayed APs: The number of rows that the table will display

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Survey Screen Map Window

The figure shows the Map window on the Survey screen, with a site map in it. A map will appear in the Map window only when it is selected (checked) in the Project window. Otherwise, the screen will be blank. By default, a site map will automatically open in the Map window when you open a Survey project. Before starting a site survey, it is important to make sure that the project or site map matches the location to be surveyed.

After a survey is started, information such as access point locations, survey paths, and data collection points may also appear on the map.

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Survey ConfigurationSurvey Configuration screen

SettingsColor802.11ScanMapPoint (For outdoor surveys)

Your survey results are affected by AirMagnet Survey settings. Therefore, it is highly recommended that you configure the parameters in a way that allows you to achieve what you intend to accomplish. The configuration of AirMagnet Survey is conducted in the Survey Configuration window, which can be accessed through one of following:

From the Main Menu, navigate to File > Configure.

From the Toolbar, choose the hammer icon.

The figure shows the Survey Configuration screen, which contains five tabs across the top of the screen, each representing a specific task for configuring the application.

Settings Tab The options on the Settings tab define the way that data is collected during a survey. The Settings tab includes the following parameters:

Ignore APs Whose Max Discovered Signal Strength Is Less Than: Specify a threshold value for access point signal strength. Access points whose signal strength falls below that value will be ignored. The value of signal strength ranges from 0 (strongest) to -100 (weakest).

Hide Ignored Access Point: If enabled, access points whose maximum signal strength falls below the threshold will not be shown in the Channel/SSID Tree in the Display screen.

Auto Logging Data Period: Enter a value in seconds. This allows you to set the automatic data sampling interval. The default value is once per second.

Beep When Logging Data: If selected, AirMagnet Survey will beep each time that it logs data. It serves as an indicator that Survey is working properly. The frequency of the beeping depends on the data sampling interval.

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Auto Sampling Through Path: If selected, AirMagnet Survey will automatically mark data sampling points on the site map, which are represented by the red dots along the survey path. The data sampling interval will be determined by the value specified in Auto Logging Data Period.

Sampling On Click Only: If selected, AirMagnet Survey will sample data only when you choose the site map.

Auto Position APS with Signal Strength Greater Than: If you choose this option, you may also need to set a signal strength value in the space below. AirMagnet Survey will automatically place the access points that meet your specification in their optimal locations on the site map.

Prompt for Refresh After AP Location Change: If enabled, AirMagnet Survey will prompt you to refresh the screen each time that you reposition an access point.

Enable Survey Range Indicator: If enabled, AirMagnet Survey will automatically mark the survey data sampling range (radius) as you choose the site map.

Enable GPS Port: If enabled, the Configure button will be enabled so that you can configure Global Positioning System (GPS) settings.

Ch Interference Setting: Opens the Interference dialog box, where you can configure the minimum values of access point signals that the program will take into account when calculating signal interference and noise.

Data Proc Option: Opens the Data Processing Option dialog box, where you can customize the resolution that the program uses to process data. This feature is used for processing data on the Display screen.

Spectrum Analyzer: Choosing this button will open the Spectrum Analyzer dialog box, where you can choose to show or hide the Spectrum Analyzer window, which, if enabled, will appear below the Map window on the Survey and Display screens.

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Channel InterferenceDefault settings for interfered and interfering are -67 and -87Parameter adjustable

The definitions of signal interference and noise are rather subjective. They may vary from person to person, depending on perception and level of tolerance. For instance, –67 dBm or –87 dBm may be considered as interference or noise by one person but be considered acceptable by another.

The Ch Interference Setting button allows you to specify the minimum value that the program should consider as interference or noise when calculating these parameters. Once specified, any signal from an adjacent access point that falls below the value will not be considered as interference or noise by the program.

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Signal to Speed Mapping Table

Clicking the Speed Map button brings up the Signal To Speed Mapping Table, which allows users to specify speed transmission information for the card in use. This is important for speed data calculated for passive or virtual surveys.

The values displayed in the speed mapping table relate to the minimum signal strength required in order to transmit data at a given speed. For example, the default value for transmitting at 6 Mb/s for 802.11g traffic is –86 dBm.

Note The default values provided in the table are based on Receive Radio sensitivity values for most wireless cards. You should only modify values that do not match those of the wireless adapter in use.

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Configuring Legend Color ScreenThe Color tab allows you to choose how colors are displayed.

Color Tab This feature allows you to set and change the color scheme on the Legend, which will affect the color scheme displayed in the Map window on the screen. The Color tab includes the following parameters:

Color Scheme: Choose one of the color schemes. Each radio button represents a color scheme, which affects the overall color scheme of the Legend. Your selection will be automatically reflected on the Legend after you click OK.

Outline Color: Change any of the color values (Red, Green, Blue), or click Choose Color to choose a color from the Color box. This option affects the color of the border around areas (for example, cells) covered by different access points.

Automatic Contrast Adjustment: If selected, AirMagnet Survey will automatically adjust the color contrast as you drag the color box up or down the Legend.

Granular Color Bar Selection: If selected, AirMagnet Survey will change the color shade one grade at a time as you drag the color box up or down the Legend.

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Configuring 802.11 ParametersThe 802.11 tab lets you configure for a select network SSID.When you configure for a select SSID, all the parameters on this tab will be applied to the wireless network card, including security.

802.11 Tab Depending on the security mechanism of the WLAN, you may be asked to provide the network security settings (for example, Wired Equivalent Privacy [WEP], Lightweight Extensible Authentication Protocol [LEAP]) in order to collect data on a specific access point that you are associating with while conducting an active survey. In this situation, no site survey can be conducted unless you provide the correct security settings of the access point.

The 802.11 tab includes the following parameters:

SSID: Choose ANY (default) if you do not have a specific SSID to associate with. Choose an SSID if you want to associate with that SSID. When the active tools, such as DHCP or ping, try to associate with a specific access point within a given SSID, all the parameters configured in this screen for this SSID will be applied to the wireless network card.

Network Type: Choose either Infrastructure or Ad-Hoc.

TX Rate: Choose the transmission rate that AirMagnet Survey will use.

Channel: Choose a channel. This option will be available only when Ad-Hoc network type is selected.

Packet Retries: Choose a maximum number of transmission retries at the 802.11 protocol level.

RTS Threshold: Choose a threshold of packet length to trigger the use of the 802.11 Ready to Send/Clear to Send (RTS/CTS) mechanism.

Frag. Threshold: Choose an 802.11 frame fragmentation threshold.

Power Save Mode: Choose Active or Power Save (mode).

Preamble Mode: Choose Long or Short (802.11 preamble mode).

Auth. Algorithm: Choose Open or Shared Key (authentication).

Country: Specify the country where the survey is conducted.

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Delete: Click Delete to remove the SSID.

Default: Click Default to restore the configuration to factory default.

Authentication: Opens the Wireless Authentication dialog.

Advanced: Opens the Advanced Driver Settings dialog box, where you can configure LEAP and 802.11a regulatory domain.

Calibration: Opens the RF Calibration dialog box to allow you to calibrate the SSID.

Configuring Authentication Mechanism Some WLANs may require authentication if you want to use your AirMagnet Survey to conduct an active survey on the network. AirMagnet Survey provides the following authentication options:

WEP

LEAP

Host-based EAP

Wi-Fi Protected Access pre-shared key (WPA PSK)

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Channel ScanFor AirMagnet to collect data on a channel, ensure that channel is enabled in the Scan tab.You can set the following:– Enable All – Clear All– Reset– Select Country Code Channels– Extended– Scan Time

Scan Tab Configuring channel scan settings allows you to specify the channels that you want the wireless network card to scan and to set the scan frequency.

In order for AirMagnet Survey to record data from the channels of interest, make sure that you have the scan feature enabled for those channels using this screen. A common reason that no data are recorded for a specific channel is the fact that the scan feature is not enabled on that channel.

The Survey Scan tab includes the following parameters:

Enable All: Enables all channels, if you want to scan all channels

Clear All: Disables all channels

Reset: Resets to factory default settings

Scan Time: Sets the scan interval time

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Extended Channel Scanning Settings for 802.11aYou have the option to scan extended channels that are not normally used but may be used by hackers to attack the network.

Extended channels refer to the 802.11a channels not normally used by most businesses or countries. You can scan only the standard country channels by clicking the Select Country Code Channels button. However, since hackers and outside sources may not always choose to attack from the usual channels, you may scan the extended ones that are normally unused by clicking the Extended button.

You may configure as many channels as you desire for 802.11a scanning. Survey will include the channels you choose here in its scanning process along with the standard channels. Further, you can use the tools at the bottom of the dialog box to customize how Survey scans the channels that you do not check.

During a normal scan, Survey will scan the standard channels and the extended channels that you choose. It will then scan a number of the 802.11a channels that you do not have selected, which you can control using the Scan Time and Scan Window options at the bottom. Scan time refers to the amount of time spent on the scan, and the window is the number of channels scanned at a time. After your specified window of channels has been scanned, Survey will rescan the standard channels and then continue with the extended channels.

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Conducting a Site Survey with AirMagnet

Open Project

To create an indoor site survey project, import a site map and specify some physical properties of the site. To conduct a preinstallation site survey, complete the following steps:

Step 1 Go to the site with a PC that is loaded with the following:

AirMagnet Survey or Survey PRO (Recommended).

A wireless network card (inserted in the wireless network card slot).

A Survey project. It is recommended that you have the Survey projects created ahead of time so that you can make sure that the site map is accurate and is of good resolution.

Step 2 Upon arrival at the survey site, place the access point at one of the possible mounting locations.

Step 3 Start AirMagnet Survey by navigating to Start > All Programs > AirMagnet Survey > Survey. This will launch AirMagnet Survey.

Step 4 Choose Open Project from the toolbar. Then find and open the Survey project file (.svp) of interest. The selected project file appears in the Project window and the site map will display in the Map window.

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Configure AirMagnet Survey PRO This topic describes how to configure AirMagnet Survey PRO. Your survey results are affected by the AirMagnet Survey settings. Therefore, it is highly recommended that you configure the application parameters in a way that allows you to achieve what you intend to accomplish.


Configuring AirMagnet Survey PROSelect Media Type

Choose the hammer to configure SSID and the power settings.

To configure AirMagnet Survey PRO, follow these steps:

Step 1 If the project has more than one site map, choose the map that you want to display in the Map window (if it is not already opened).

Step 2 Choose the media type tab and then select a media type from the drop-down menu.

Step 3 Choose the hammer in the toolbar to get to the configuration menu.

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Configuring AirMagnet Survey PRO (Cont.)

Select the SSID of the survey access point.

Click Advanced to set the wireless adapter power setting to match the survey access point.

Step 4 Select the 802.11 tab.

Step 5 From the drop-down menu, choose the SSID of the access point with which you are performing the site survey.

Step 6 Click the Advanced button.

Step 7 In the Advanced Driver Settings dialog box, choose the matching power setting that you have set on the access point.

Note Depending on the client, the power settings may not always match. Try to set them as close as possible.

Step 8 Click Apply.

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Configuring AirMagnet Survey PRO (Cont.)

Select Channel WidthHighest 802.11n speeds achieved using channel bonding (40-MHz channels)

For 802.11n surveys, the highest throughput is achieved by using channel bonding (combining two channels). You must set this on both the client and the access point to enable it.

To select 40-MHz channels, follow these steps:

Step 1 Select the Settings tab.

Step 2 Check the PHY Data Rate Map check box.

Step 3 Select the 802.11n tab.

Step 4 From the Channel Width drop-down menu, select 40 MHz.

Step 5 Click OK.

Step 6 Click OK.

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Access Point Setup ExampleExpress Setup page:– Host Name: survey1– Static IP address: 192.168.1.100– Subnet Mask: 255.255.255.0– Role in Radio Network: Access Point

SSID Manager page under Security tab:– SSID: survey1– Interface SSID to be applied: Radio1-802.11n 5 GHz– Client Authentication Settings: Open Authentication

The figure shows an access point setup as an example of Cisco IOS GUI.

The Express Setup page includes these parameters:

Host Name: survey1

Static IP address: 192.168.1.100

Subnet Mask: 255.255.255.0

Role in Radio Network: Access Point

The SSID Manager page (under the Security tab) includes these parameters:

SSID: survey1

Interface SSID to be applied: Radio1-802.11n 5 GHz

Client Authentication Settings: Open Authentication

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Access Point Setup Example (Cont.)Secure username and password for access point (recommended)Encryption (optional, but recommended)Radio interface page Select Radio1-802.11n 5 GHzSelect Settings tab– Enable radio– Role in Radio Network: access point– Data Rates: Disable all data rates under 24.0 Mb/s– Require 24.0 Mb/s– OFDM Transmitter Power (dBm): 11– Client Power (dBm): –11– Default Radio Channel: 161 - 5805 – Set Channel Width to Above 40 MHz

Access Point Secure User Name and Password (Recommended): This will keep any pranksters from taking control of your survey access point while you are conducting your survey.

Encryption (Optional but Recommended): Encryption will more than likely be applied to the WLAN. AirMagnet supports the following authentication and encryption types:

— Authentication

LEAP

Host-based EAP

WPA PSK

— Encryption

WEP

WPA Temporal Key Integrity Protocol (TKIP)

Note 802.11n security is WPA2 only, which is currently not supported by AirMagnet, so encryption is not enabled for 802.11n surveys.

Radio Interface page includes the following:

— Enable Radio

— Role in Radio Network: Access point

— Data Rates: Disable all data rates under 24.0 Mb/s

— Require 24.0 Mb/s

— OFDM Transmitter Power (dBm): 11

— Client Power (dBm): 11

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— Default Radio Channel: 161 - 5805 GHz

— Set Channel Width to above 40 MHz

— All other settings for this page should be left at default

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Conduct the Survey This topic describes how to conduct a data site survey with AirMagnet Survey PRO. AirMagnet Survey PRO can be operated in two survey modes: active and passive. They are used for different purposes.


Conducting a Site Survey with AirMagnetPerform two types of surveys:– Pre- and post-installation, also termed audit or verification

of pre-installation surveyThree survey modes:– Active: Used to send data and retrieve data from the access

point recording signal levels, retries, lost packets, and so on– Active with Iperf for greenfield survey:

Two modes of operation:– AP mode: For surveying a single access point– SSID mode: For surveying a network of access points

– Passive: Used to capture all 802.11 traffic in an environment, normally not SSID-specific

AirMagnet Survey can be used for both pre- and postinstallation WLAN surveys to collect RF data on the site. The surveys can be performed without having access points permanently installed in their locations. In addition, there is no need to adjust channels from the access points prior to a survey because AirMagnet Survey allows you to do channel separation when analyzing the data in the Display screen, where you can change channel allocation when a suitable channel combination is identified through channel simulation. This saves both time and resources that would otherwise be required for a conventional site survey.

AirMagnet Survey can be operated in three survey modes: active, active with Iperf for greenfield survey, and passive. They are used for different purposes.

In an active survey mode, the wireless network card actively associates itself with the selected access point or SSID, sending and receiving RF packets to and from the access point or SSID. Selecting a specific access point will let the wireless network card associate only with that access point, whereas selecting an SSID will let it associate with the access point that has the strongest RF signal within the SSID group.

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Active with Iperf survey mode allows AirMagnet Survey PRO to sync with an Iperf server to test throughput on the uplink and downlink. These up and down data rates are displayed in the data window when the survey is active.

In a passive survey mode, the wireless network card does not associate itself with any particular access point or SSID. Instead, it simply listens to the RF data moving through the site, detecting and recording all RF signals and noises in the environment. By default, AirMagnet Survey opens in the active survey mode when it is operated in Survey screen.

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Overview for Conducting Preinstallation Site Surveys

Select placement of the first access point. Watch your signal level and try to find the cell edge for the data rate that you are surveying for.Walk the coverage area clockwise for one survey capture and counter-clockwise for the second survey capture.Save the survey data at the end of each survey. Continue adding access points as needed until the floor or facility is covered with 10 to 15 percent overlap.

Preinstallation survey procedures can be summarized as follows:

Determine the possible locations where an access point should be placed.

Place the access point in the most desirable location, and conduct as many active surveys as needed to ensure that the access point intended coverage area is fully covered by the surveys. Save the survey data at the end of each survey; you may end up having several active survey data files for the access point at one location.

Repeat until the facility is covered.

Remember to save the survey data at the end of each survey.

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Overview for Conducting Preinstallation Site Surveys (Cont.)

Conduct one passive survey of the floor or facility with the SSID set to Any.After you have completed coverage of the floor or facility, merge the survey data.Merge the survey data by access point.– Then merge the merged access point data files.– Finally, merge the merged access point data file with the

passive survey data file.After you have completed the survey, review the data for proper placement of additional access points to fill in any null areas.

Conduct one passive survey with the SSID set to Any, and save the survey data.

Switch AirMagnet Survey to the Display screen, and merge all the active and passive survey data files.

Note For better results, it is recommend that (1) you merge the active survey data files collected at each location first, (2) then merge the merged active survey data files from all locations, (3) and then merge the passive survey data file with the merged active survey data file that included active survey data from all locations. This will provide you with the most comprehensive RF data about the access point and the site environment.

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Conducting an Active Survey

Complete the following steps to conduct an active survey:

Step 1 From the Data window, check the Active (AP association) check box. From the drop-down menu on the left, choose AP. Choose a specific AP from the drop-down menu.

Step 2 Click the green arrow in the top right toolbar to begin the survey. A message box pops up prompting you to specify the location of the access point.

Note This message box appears only when you are associating with a specific access point when performing an active survey.

Step 3 Click Yes. An AP icon showing the name of the selected access point appears in the Map window.

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Conducting an Active Survey (Cont.)

Choose the AP icon and drag the AP to the location that corresponds to its location on the site. Then choose the green arrow in the top right tool bar to start surveying the access point coverage area.

Step 4 Choose the AP icon, hold down the mouse button, and drag the access point to the location that corresponds to its location on the site.

Step 5 Click the green arrow in the top right toolbar again. The survey resumes.



Step 6 If you need to take a break, click Pause. To restart the survey, select the next data point.

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Step 7 Start walking around the intended coverage area for the access point and a little beyond with your laptop. When you turn and move in a different direction, move the survey guide to that point on the map and left-click.

Step 8 Click the round, red button to stop the survey after you have collected enough data points. A window appears prompting you to save the survey data.

Step 9 Highlight the default name of the survey and type a unique name over it.

Step 10 Click OK. The newly recorded survey data will appear under Survey Path in the project window.

Note The blue dotted line on the site map represents the survey path covered by a survey. The blue dots indicate the data logging points that can be configured using File > Configure > Settings, whereas the red dots indicate the place you choose on the site map.

Step 11 Place the same access point at the other potential locations, and repeat the steps to complete as many active surveys as needed.

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Conducting a Passive Survey

Choose Passive Survey in the drop-down list and the SSID of ANY. Click the green arrow in the upper left toolbar and re-walk the survey area.

To perform a passive survey, complete these steps:

Step 1 From the Data window, choose Passive Survey from the Survey Type drop-down list to perform a passive survey.

Note For best results, it is recommended leaving the SSID field to ANY while performing a passive survey. This will enable you to collect comprehensive RF signal data from the site environment.

Step 2 Take your laptop with you and conduct the passive survey around the perimeter of the site, using the same techniques as described for the active surveys.

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Conducting a Passive Survey (Cont.)

Step 3 Click the red button in the top right toolbar when you have collected enough data.

Step 4 Save the survey data when prompted. Use a unique file name.

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Merge and Display Data This topic describes how to merge and display data collected during the active and passive survey. Each survey data file contains all the RF data recorded during a survey.


Display Data

Processing Data Merging Active and Passive Data

Each survey data file contains all the RF data recorded during a survey. By default, no survey data will be displayed in the Map window when you switch to the Display screen. You need to choose a survey data file to display it. Complete the following steps to display the data:

Choose the radio button in front of the data file. The Loading Data File window appears, showing the various components of the file as they are being loaded. The data will be mapped out in the Map window after the file is loaded. The time it takes to open a data file depends on the size of the file. Some survey data files (for example, passive surveys) may take significantly longer to load, mainly because of the enormous amount of data contained in those files.

Note For better results, it is recommend that (1) you merge the active survey data files collected at each location, (2) then merge the merged active survey data files from all locations, (3) and then merge the passive survey data file with the merged active survey data file that included active survey data from all locations. This will provide you with the most comprehensive RF data about the access point and the site environment.

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AP1 (Signal)

Place additional access points here and adjust power to fill in weak areas.

This figure illustrates the signal coverage area. The bottom left and top corners will need to have additional access points added to fill in for the areas that have low signals. Adding an access point to the conference room on the bottom left corner and adjusting the power to stabilize that area of the building for a proper signal level is recommended.


AP Data Merge (Noise)

In this example, the noise recorded during the active surveys is low, which is good.

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AP Data Merge (SNR)

In this example, the SNR view looks similar to the signal view.


AP Data Rate (Speed)

The overall speed looks good. There are only a couple of spots where the speed is at 54 Mb/s, shown in green. Access points 1 and 4 were surveyed with 20-MHz wide channels whereas access points 2 and 3 were surveyed with 40-MHz wide channels. This is why the left side of the building is at the higher data rates.

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AP Data Merge (Retry Rate)

Many retries at 802.11n speeds

This example shows excessive retries. This might be common to 802.11n because of the excessive speeds in play.


AP1 and AP 4 (Packet Loss Rate)

AP4AP1

In this example, AP1 indicates that packets were lost, whereas AP 4 indicates that there were no packets lost.

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Active and Passive Merged Files (Signal)

This is an example of the overall view of AP1 and AP4 active and passive surveys merged. Also shown are the survey paths.

The access point settings included:

AP 1 2 3 4

Channel 165 161 153 40

Channel Width 20 MHz 40 MHz 40 MHz 20 MHz

dBm 11 5 11 5

Power 12 mW 3 mW 12 mW 3 mW

Client Power 20 mW 5 mW 20 mW 5 mW

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Generate a Report This topic describes how to generate reports using the reports feature in AirMagnet Survey PRO. AirMagnet Survey PRO can automatically convert any survey data shown on the Display screen into a variety of data reports, which can be viewed, printed, or distributed from the Reports screen.


Survey Reports

These reports are available:

Overall Coverage Report by Channel: Contains data about the overall RF signal coverage on the selected channel

Overall Coverage Report by SSID: Contains data about the overall RF signal coverage of the selected SSID

Overall Coverage Report by AP: Contains data about the overall RF signal coverage of the selected access point

Per Channel Report: Contains signal data of the selected channel

Per SSID Report: Contains signal data of the selected SSID

Per AP Report: Contains signal data of the selected access point

Channel Interference Report: Contains data about the channel interference

AP Interference Report: Contains data about the interference between the access points

AirWISE Report: Shows data relating to the AirWISE screen

Spectrum Analyzer Report: Shows reports on Spectrum Analyzer data

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SummaryDifferent construction materials have different effects on RF propagation.The WLAN should be tested at peak user density. The usable signal range is typically from –60 to –80 dBm.To start an AirMagnet Survey project, you need a digital floor plan of the facility.AirMagnet Survey PRO can perform pre-site surveys and postinstallation site surveys.Higher data rates can be achieved by using channel bonding (40-MHz wide channels).AirMagnet Survey PRO has report generation capabilities.

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Lesson 4

Conducting a Layer 2 Site Survey for Voice Applications

Overview Before deploying the Cisco Unified Wireless IP Phone 7921G or Cisco Unified Wireless IP Phone 7925G into a production environment, a site survey must be completed. During the site survey, the RF spectrum is analyzed to determine which channels are usable in the desired band (2.4 GHz or 5 GHz). Typically, there is less interference in the 5-GHz band as well as more nonoverlapping channels, so 5 GHz is the preferred band for operation. The site survey will include heat maps showing the intended coverage plan for the location. The site survey will also determine which access point platform type, antenna type, and access point configuration (channel and transmit power) to use at the location.

Objectives Upon completing this lesson, you will be able to conduct a Layer 2 site survey for voice applications using AirMagnet Survey PRO. This ability includes being able to meet these objectives:

Describe the RF recommendations for a VoWLAN site survey for 2.4-GHz phones

Describe the RF recommendations for a VoWLAN site survey with 5-GHz phones

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IEEE 802.11b/g/n and VoWLAN Deployments This topic describes the RF recommendations for a VoWLAN site survey for 2.4-GHz phones. With the introduction of voice to a predominantly wireless data network, the methodology of site surveys needs to be altered. Surveying for wireless voice coverage requires more effort and time than for data-only coverage at the same site. A voice survey requires planning of coverage plus the planning of capacity.


2.4-GHz Surveys for VoiceData rates:– Disable rates under 12 Mb/s– If no 802.11b clients, disable data rates of 1, 2, 5.5, 6, 9,

and 11 Mb/s.Basic (required ) data rate is 12 Mb/s

– If 802.11b clients exist, disable data rates of 1, 2, 5.5, 6, and 9 Mb/s.

Basic (required ) data rate is 11 Mb/s– Set only the lowest data rate as the single basic rate for

multicast traffic.– Capacity and throughput are reduced when lower rates

are enabled.

You should disable rates below 12 Mb/s for IEEE 802.11b/g deployments, in which capacity and range are factored in for best results. If 802.11b clients are not allowed in the WLAN, you should disable data rates of 1, 2, 5.5, and 11 Mb/s. When 802.11b clients exist in the wireless network, an 802.11b rate must be enabled and only an 802.11b rate can be configured as a basic rate. In this case, you should enable the data rates 11 Mb/s and higher. The table shows the recommended data rate configuration.

802.11 Mode Basic (Mandatory) Data Rates

Supported (Optional) Data Rates

Disabled Data Rates

802.11b 11 Mb/s None 1, 2, and 5.5 Mb/s

802.11g 12 Mb/s 18 to 54 Mb/s 6 an 9 Mb/s

802.11b/g 11 Mb/s 12 to 54 Mb/s 1, 2, and 5.5 Mb/s

Note Some environments may require that you enable a lower rate due to use of legacy clients, environmental factors, or maximum range as required. Set only the lowest data rate enabled as the single basic rate. Multicast packets will be sent at the highest basic data rate enabled. Note that capacity and throughput are reduced when lower rates are enabled.

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2.4-GHz Surveys for Voice (Cont.)Call capacity– 802.11a and 802.11g can support up to 27 bidirectional RTP

streams at 24 Mb/s.– 13 bidirectional RTP streams can be supported at 6 Mb/s.– The number of calls depends on the data rate and channel

utilization.– Using U-APSD instead of PS-Poll provides higher capacity.

You should design the network to accommodate the desired call capacity.

The access point can support up to 27 bidirectional Real-Time Transport Protocol (RTP) streams for both 802.11a and 802.11g at a data rate of 24 Mb/s or greater. To achieve this capacity, you must use unscheduled automatic power-save delivery (U-APSD) and have minimal WLAN background traffic and RF utilization.

The number of calls may vary depending on the data rate, initial channel utilization, and the environment. At 6 Mb/s, the access point can support up to 13 bidirectional RTP streams. Using U-APSD instead of power save poll (PS-Poll) provides higher call capacity because U-APSD is more efficient and has limited management overhead.

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2.4-GHz Surveys for Voice (Cont.)DTPC

– If using autonomous APs, set the client power to 20 mW or 25 mW and the AP Tx power to the power nearest to 20 mW or 25 mW. Do not default settings to max on AP or DTPC will not function.

– If using lightweight APs, set the AP Tx power to the power nearest to 20 mW or 25 mW.

– In the beacons and probe responses, the autonomous APs advertise the Tx power set in the client Tx power field.

– In the beacons and probe responses, the lightweight APs advertise the current Tx power of the AP.

– To minimize the chance of one-way audio at an RF level, try to maintain a balance in signal levels between the AP and phone.

– By default, the Cisco Unified Wireless IP Phone uses Tx power advertised in the beacons and probe responses.

Cisco recommends using Dynamic Transmit Power Control (DTPC) for all clients. Many clients, such as Vocera and Ploycom SpectraLink, do not use DTPC. In such a case Cisco recommends using a power level between 20 and 25 milliwatt (mW) on the access point and having the client devices configured to a matching power level, or a slightly higher power level if there is no matching power level. Therefore, if the access point is set to 25 mW and the client does not have a 25-mW power level, set the client to 30 mW, which is the Cisco recommendation for 2.4 GHz.

Most sites that have 5 GHz enabled are trying to use the access point to cover with 5 GHz the same coverage as the 2.4-GHz coverage. Cisco recommends that the 5-GHz power level set on the access point matches the highest power level of the phone client. In the case of the Cisco Unified Wireless IP Phones 7921 and 7925, that power level will be 40 mW.

The 5-GHz Cisco phone has a receive sensitivity of 18 Mb/s that is equal to the receive sensitivity of the Cisco Unified Wireless IP Phone 792x at 11 Mb/s. The 5-GHz channels typically have 5 dB or more lower noise floor, so the signal-to-noise ratio (SNR) is favorable.

The IEEE 802.11n access points from Cisco will improve the 5-GHz performance of the 5-GHz side of the Unified Wireless IP Phones 792xx, making the coverage area on the 5-GHz side even more likely to match that of 2.4-GHz 802.11b.

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2.4-GHz Surveys for Voice (Cont.)Nonoverlapping channels– Use channels 1, 6, and 11 (North America)– Use channel 14 as a fourth nonoverlapping channel (Japan)

A total of 14 channels are defined in the 802.11b/g channel set. Each channel is 22-MHz wide, but the channel separation is only 5 MHz. This leads to channel overlap, so that signals from neighboring channels can interfere with each other.

In North America, channels 1, 6, and 11 are the three usable nonoverlapping channels for access points and wireless endpoint devices. In Japan, the nonoverlapping usable channels for 802.11b are 1, 6, and 11. Channel 14 can be used as the fourth nonoverlapping channel.

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2.4-GHz Surveys for Voice (Cont.)20 percent overlap per cell– This ensures good handoff between access points on adjacent

channels.

Each cell in the network should overlap with the adjacent cells in order to facilitate uninterrupted handoff as a client moves between cells, and to provide a minimum service even in case of access point failure. When deploying phones in an 802.11b/g environment, you must use nonoverlapping channels and allow at least 20 percent overlap between adjacent channels.

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2.4-GHz Surveys for Voice (Cont.)Signal strength and coverage– –67 dBm cell

edges, 25 dB SNR– Ensure PER no

higher than 1 percent

– Design WLAN for 24 Mb/s; 36 to 54 Mb/s can optionally be enabled

– 19 dBm of separation for same channel cells

PER = packet error rate

At the edge of each voice cell, the Received Signal Strength Indicator (RSSI) measurement should be –67 dBm or higher, and there should be a separation between adjacent access point channels of –86 dBm if you are using a Cisco Unified Wireless IP Phone 7921G. The –67 dBm threshold is a general recommendation for achieving a packet error of 1 percent, which requires an SNR value of 25 dB (92-dBm noise level) with a –67 dBm signal being maintained.

When you survey a site without an installed 802.11 network, plan to use two or three access points to measure cell coverage and cell overlap. The cell edge for the Cisco Unified Wireless IP Phone 7921G at the 11-Mb/s data rate is –67 dBm. The signal strength at the edge of that cell must be 19 dB weaker than the signal from the next cell on the same channel. That means that at the –67 dBm edge of the cell, the next cell on the same channel should measure –86 dBm, as shown in the figure.

To achieve maximum capacity and throughput, the WLAN should be designed to 24 Mb/s. Higher data rates (36 to 54 Mb/s) can optionally be enabled.

You should set the minimum data rate to 11 or 12 Mb/s for the 2.4-GHz band (dependent upon 802.11b client support policy) and 12 Mb/s for the 5-GHz band, which should also be the only rate configured as a basic rate.

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Access Point ConfigurationSecurity > SSID Manager Enter SSID, enable Radio0-802.11N, 2.4GHz, Open Authentication, NO ADDITION

To configure the Cisco Aironet 1250 Series Access Point for a 2.4-GHz voice site survey, follow these steps:

Step 1 Navigate to Security > SSID Manager.

Step 2 In the Service Set Identifier (SSID) text box, enter the SSID.

Step 3 Check the Radio0-802.11N, 2.4GHz Interface check box.

Step 4 Ensure that Open Authentication with NO ADDITION is checked.

Step 5 Click Apply.

Step 6 Click OK.

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Access Point Configuration (Cont.)Network Interfaces > Radio0-802.11N2.4 GHz > Settings

Enable Radio

Step 7 Navigate to Network Interfaces > Radio0-802.11N, 2.4 GHz > Settings. Click the Enable radio button after Enable Radio to enable the radio interface.

Step 8 Click the Access Point radio button for the Role in Radio Network.

Step 9 In the Data Rates pane, click the Require radio button for 12.0Mb/sec.

Step 10 Click the Enable radio buttons for 18.0Mb/sec through 54.0Mb/sec.

Step 11 Disable the 1 through 11.0Mb/sec. by clicking the Disable radio buttons.

Step 12 Disable all the modulation coding scheme (MCS) Rates by clicking the Disable radio buttons if you are surveying with an 802.11n-capable adapter.

Step 13 For both the Transmitter Power and Client Power, click the 14 dBm radio buttons.

Step 14 Select Channel 1, 6, or 11 from the DefaultRadio Channel drop-down menu.

Step 15 Select 20 MHz from the Channel Width drop-down menu.

Step 16 Click Apply.

Step 17 Click OK.

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AirMagnet Survey PRO ConfigurationCreate ProjectSpecify project nameImport floor planSelect Open Space – Office CubiclesEnter AP Tx powerRecalibrate floor planSelect Survey from the Navigation barSelect 2.4 GHz as the Media TypeClick file > configure > 802.11Enter AP SSIDSelect Short for Preamble Mode

To create a new project for an indoor site survey, follow these steps:

Step 1 From the toolbar, select the Project Wizard icon or from the Main Menu, choose File > New Project.

Step 2 Choose Import Site Image to locate and import the site map of the location where surveys will be conducted.

Step 3 For Survey Environment, check the Open Space – Office Cubicles check box.

Step 4 For AP Default Power, enter AP transmit (Tx) power.

Step 5 From the toolbar, select the protractor to recalibrate floor length and width.

Step 6 From the Navigation bar, select Survey.

Step 7 From the Media Type drop-down menu, select 2.4 GHz.

Step 8 Navigate to File > Configure and click the 802.11 tab.

Step 9 In the SSID text box, enter the access point SSID.

Step 10 From the Preamble Mode drop-down menu, select Short.

Step 11 Click OK.

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Place Access Point on Floor Plan

Click the Start Survey button

Click Yes and place AP icon where the survey AP is located in the building

Select Active SurveySelect AP and your AP from the dropdown menu

Step 12 From the Survey Type drop-down menu, select Active Survey.

Step 13 From the toolbar, click the green arrow to start the survey.

Step 14 When you are prompted to specify the access point location, click Yes and place the access point on the floor where it actually exists.

Step 15 From the toolbar, click the green arrow to start the survey again. This time AirMagnet will associate to the access point.

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2.4-GHz Survey for Voice

Watch for -67 cell edges and an SNR of 25 or higher

Conduct a survey of the first cell. Watch the signal and SNR to find the edge of the cell. Keep the cell edges at –67 dBm and the SNR should be 25 or better. When you find your cell edges, you are ready to move the access point to the next location.


Save Your Data

Stop Survey button

Save AP survey data with a unique file name such as “ActiveSurvey2.4GHz Voice AP1”

When you are ready to stop the survey, click the arrow in the right tool bar. You will be prompted to save the survey results for your first active survey. Active survey1 is the default file name. Change this naming convention to something unique before saving.

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Change Channel on Access Point

Change channel on access point before surveying for the next access point.

Before surveying for coverage of the next access point, be sure to change the access point channel for the AP2 location. Access point 2 should be placed on channel 6 or 11 because access point 1 is operating on channel 1.


Survey for Voice AP 2

Move the access point to the next location, then click the green arrow to start the survey.

Click the green arrow in the menu on the right to start the survey and move the access point to the next chosen location.

Survey the next access point. Verify that you have at least 20 percent overlap with the first access point location and that the cell edges and the SNR meet the recommended requirements.

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Save Data for AP2

When you have defined the cell coverage for AP2, stop the survey and save your data. Remember to use a unique name to associate the saved file with AP2. Continue to map your cell coverage area until the facility is covered. Remember to use nonoverlapping channels. Check to ensure that each cell on the same channel has at least 19 dBm of signal separation.

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Passive Site Survey

When you have mapped out access point coverage with active site surveys, perform one passive site survey per floor.Save the passive survey.

Perform one passive site survey per floor. The passive site survey is to gain information about the environment and other interference factors. Select Passive Survey from the Survey Type drop-down menu. Select SSID and then select ANY. Walk the entire floor to collect the passive survey data.

Click the arrow to stop the survey when you are finished walking the floor. Save the file with a unique name.

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Merge FilesMerge active survey AP files first.Merge merged active survey AP files next.Merge merged active survey AP file with the passive survey AP file last.

To merge the data files, first merge the active access point surveys. Next, merge the merged active access point survey files. Finally, merge the merged active access point surveys with the passive survey file. It is recommended that they are merged in this order for best results.

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Review Captured DataReview captured data for:

20 percent overlapData rate of 24 Mb/sCo-channel Interference–67 dBm signal or betterExtreme packet loss19 dBm of signal separation for same channel access points

Review the captured data to ensure that there is 20 percent cell overlap, the data rate is 24 Mb/s or better, there is a minimum amount of co-channel interference, as well as signal levels of –67 dBm or better. Look for any extreme packet loss. The –67 dBm requirement is to minimize packet loss. Additional access points may be required to meet the perimeter requirements. These additional access points are unlikely to add capacity to the WLAN system (particularly in the 2.4-GHz band), and the additional access points are unlikely to have great impact upon the overall co-channel interference characteristics of the deployment. To avoid co-channel interference, use a lower power, if necessary. Access points on the same channel should have at least 19 dBm of signal separation. While this may not always be possible, that is the model that has been set.

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IEEE 802.11a/n and VoWLAN Deployments This topic describes the RF recommendations for a Voice over WLAN (VoWLAN) site survey with 5-GHz phones. Although there are 23 nonoverlapping channels in the 5-GHz band, it is generally recommended to use the lower four channels and upper four channels of the 5-GHz spectrum as the base for VoWLAN, because they do not have Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) requirements.


VoWLAN 5 GHzWhen performing a site survey for voice in the 5-GHz bands, some things do not change:– –67 dBm cell edges– 19 dBm signal separation for access points on the same

channel– 24 Mb/s or higher data rates– Disabled data rates for 802.11a: 6 and 9 Mb/s– Basic (required) data rates: 12 Mb/s– Supported data rates: 18 to 54 Mb/s

The general power levels and access point separation recommendations used for VoWLAN in the 5-GHz implementation are the same as the 2.4-GHz implementation: a power level boundary of –67 dBm and a separation between adjacent access point channels of –86 dBm. Given the lower noise floor in the 5-GHz bands, the overlap recommendation may be reduced to 15 percent. A 20 percent or higher overlap can still be used if desired. It provides a higher availability design and takes into account that the use of the 5-GHz spectrum is increasing; therefore, the noise floor can be expected to rise.

The range in the 5-GHz band is different from the range in the 2.4-GHz band. However, when you use the recommended power levels and typical antennas, you obtain distances similar to those used in the 2.4-GHz band. Therefore, the same access point locations and overlap have been used for both the 2.4-GHz and 5-GHz bands. The primary difference between the two deployments is the additional capacity available due to the additional nonoverlapping channels. This difference is sufficient for the 5-GHz band to be recommended for VoWLAN deployments.

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More Channels to Choose from, 23 in AllChannels that do not require IEEE 802.11h (DFS and TPC):– UNII-1 (5.150 to 5.250 GHz) channels 36, 40, 44, and 48– UNII-3 (5.725 to 5.825 GHz) channels 149, 153, 157, 161,

and ISM 165Channels that do not require 802.11h (DFS and TPC):– UNII -2 (5.250 to 5.350) channels 52, 56, 60, 64– UNII -2 Extended (5.470 to 5.725 GHz) 100, 104, 108, 112,

116, 120, 124, 128, 132, 136, and 140It is generally recommended to use the lower four channels and upper four channels of the 5-GHz spectrum as the base for VoWLAN.– These channels do not have an 802.11h requirement.

There are different limitations imposed on each of the Unlicensed National Information Infrastructure (UNII) bands. Depending on the band, restrictions include transmit power, antenna gain, antenna styles, and usage. The UNII-1 band is designated for indoor operation, and initially required devices to use permanently attached antennas. The UNII-2 band was designated for indoor or outdoor operation, and permitted the use of external antennas. The UNII-3 band, originally intended for outdoor bridge products that use external antennas, can now be used for indoor or outdoor 802.11a WLANs as well. The channels in UNII-1 (5.150 to 5.250 GHz) are 36, 40, 44, and 48. The channels in UNII-2 (5.250 to 5.350 GHz) are 52, 56, 60, and 64 and require DFS and TPC. The channels in the new frequency range (5.470 to 5.725 GHz) are 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, and 140 and require DFS and TPC. The channels in UNII-3 (5.725 to 5.825 GHz) are 149, 153, 157, 161, 165 and do not require DFS and TPC. Not all channels in a given range can be used in all of the regulatory domains.

Although there are 23 nonoverlapping channels in the 5-GHz band, it is generally recommended that you use the lower four channels and upper four channels of the 5-GHz spectrum as the base for VoWLAN, because they do not have DFS and TPC requirements. Then add to the base of eight channels by determining which other channels are unlikely to be affected by DFS and TPC. The timing requirements of DFS and TPC can adversely affect VoWLAN call quality. If your region or location is such that you are certain DFS and TPC will not be triggered, the use of specific channels should not be an issue. If you are not certain, you should investigate. The Cisco Spectrum Expert analyzer is a good tool for starting this assessment to determine whether there are any 5-GHz signals in the area that would trigger DFS and TCP. These channels must also be supported by the WLAN clients (data and VoWLAN). It is simpler to stay with the eight non-DFS channels, but every additional channel that can be safely deployed increases the capacity of the design. In addition to avoiding the DFS and TPC channels, it is also recommended that adjacent channels be avoided in the access point channel layout, to avoid interference from the sidebands in each channel. The channel spacing and channel mask characteristics are such that the sidebands produced by an 802.11a client might interfere with the adjacent channels. It is best to avoid this potential issue in the access point layout.

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While the Cisco Unified Wireless IP Phones 7921 and 7925 support all of the 23 North American channels enabled on the current Cisco access points, many other clients do not support all those channels. For instance, the Intel 4965 does not support all 23 North American channels. It only supports 4 to 12 channels. So, if you enable channel 165 in the network, the Intel client will not associate to an access point on that channel and will be in a coverage hole.

Before enabling all 802.11a channels, it must be determined which 802.11a channels are supported by all 802.11a clients. Then set the access point and controllers to only enable the channels supported by all the 802.11a clients.

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5-GHz Channel vs. Max PowerMax power of 14 dBm– Channel 36– Channel 40– Channel 44– Channel 48

Max power of 20 dBm– Channel 149– Channel 153– Channel 157– Channel 161– Channel 165

Different RF channels have different maximum allowed power levels. In the UNII-1 band, the FCC restricts the power level of an access point to 25 mW, and the UNII-3 band is restricted to 100 mW. If you plan to use Radio Resource Management (RRM), think about coverage hole remediation. If you survey at full power and use RRM later, the correction will be limited to the client. The access point will operate at full power just to maintain its coverage area.

The recommended power setting for access points when you design voice networks is 25 mW (14 dBm). If you are using UNII-1 channels, 12 mW (11 dBm) would be more appropriate to ensure that RRM still has the ability to boost power, if it becomes necessary.

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Access Point ConfigurationSecurity > SSID Manager Enter SSID, enable Radio1-802.11N, 5GHz, Open Authentication NO ADDITION

To configure the Cisco Aironet 1250 Series Access Point for a 5-GHz voice site survey, follow these steps:

Step 1 Navigate to Security > SSID Manager.

Step 2 In the SSID text box, enter the SSID.

Step 3 Check the Radio1-802.11N, 5GHz Interface check box.

Step 4 Ensure the Open Authentication with NO ADDITION is checked.

Step 5 Click Apply.

Step 6 Click OK.

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Access Point Configuration (Cont.)Network Interfaces > Radio1-802.11N5 GHz > Settings

Enable Radio

Step 7 Navigate to Network Interfaces > Radio1-802.11N5GHz > Settings. Click the Enable radio button after Enable Radio to enable the radio interface.

Step 8 Click the Access Point radio button for the Role in Radio Network.

Step 9 In the Data Rates pane, click the Require radio button for 12.0Mb/sec.

Step 10 Click the Disable radio buttons for 6.0 Mb/sec and 9.0 Mb/sec.

Step 11 Click the Enable radio buttons for 18.0Mb/sec through 54.0Mb/sec.

Step 12 Disable all the MCS Rates by clicking the Disable radio buttons if you are surveying with an 802.11n-capable adapter.

Step 13 For both the Transmitter Power and Client Power, click the 14 dBm radio buttons if you are using UNII-3 channels. If you are using UNII-1 or UNII-2 channels, click 11 dBm for both the Transmitter Power and Client Power.

Step 14 Select a channel (36, 40, 44, 48, 149, 153, 157, 161, or 165) from the Default Radio Channel drop-down menu.

Step 15 Select 20 MHz from the Channel Width drop-down menu.

Step 16 Click Apply.

Step 17 Click OK.

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AirMagnet Configuration for 5 GHz 1. Click the New Project Wizard icon2. Specify project name3. Import floor plan4. Select Open Space –

Office Cubicles5. Enter AP Tx power6. Recalibrate floor plan7. Select Survey from the navigation

bar8. Select 5 GHz as the Media Type9. Navigate to File > Configure > 802.1110.Enter AP SSID11.Select Short for Preamble12.Set Tx Power to 20 mW

To create a new project for an indoor site survey, follow these steps:

Step 1 From the toolbar, click the Project Wizard icon or, from the Main Menu, navigate to File > New Project.

Step 2 Choose Import Site Image to locate and import the site map of the location where surveys will be conducted.

Step 3 For Survey Environment, check the Open Space – Office Cubicles check box.

Step 4 For AP Default Power, enter AP Tx power.

Step 5 From the toolbar, select the protractor to recalibrate floor length and width.

Step 6 From the Navigation bar, select Survey.

Step 7 From the Media Type drop-down menu, select 5 GHz.

Step 8 Navigate to File > Configure and then click the 802.11 tab.

Step 9 In the SSID text box, enter the access point SSID.

Step 10 From the Preamble Mode drop-down menu, select Short.

Step 11 Click the Advanced button to set the Tx Power to 20 mW.

Step 12 Click Apply and then click OK.

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Place AP on Floor Plan


Select Yes and place AP icon where the survey AP is located in the building

Select Active SurveySelect AP and your AP from the dropdown menu

From the Survey Type drop-down menu, select Active Survey (AP association), select AP from the drop-down menu and then select your access point. Click the green arrow to start the survey. A dialog box appears and asks if you would like to specify the access point location. Click Yes and place the access point icon where the survey AP is located in the building.


Start Survey of the First Access Point

Survey for -67 Cell edges 25 SNR


Click the green arrow to start the survey. To find the boundary of the access point, watch your signal level until it is at –67 dBm and the SNR stays above 25.

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5 GHz Voice SurveyWhen you find the –67 dBm cell edges, stop the survey.Save the survey AP data with a unique file name.Move the survey AP to the next location and repeat.Do not forget to change the channel on the access point between overlapping cells.Cells should have a minimum of 20 percent overlap. Continue until the area specified for coverage is covered.Perform one passive survey per floor after all active surveys have been completed.Merge active AP survey results first, merge active merged AP results next, and then merge merged active merged AP survey results with the passive survey results.Review the results.

When you find the –67 dBm cell edges, stop the survey. Save the survey data file with a unique name. Move the survey access point to the next location. Change the access point channel to a different nonoverlapping channel (you should not use adjacent nonoverlapping channels due to side-band interference). Ensure that there is a 20-percent cell overlap. Continue surveying until you have covered the facility or specified coverage area. Next, perform a final passive survey for the floor. When all active surveys and passive surveys have been completed, merge files. Merge the survey data files in this order:

Merge active AP survey files first. If you performed two or more active surveys for the same AP, merge these files first.

Merge active AP merged survey files next.

Merge merged active merged AP survey file with passive survey file, for a final merged file.

Review survey results for the entire floor or facility. You can also view results per active survey or access point.

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SummaryWhen performing a site survey for voice at 2.4 GHz or 5 GHz, cell edges should be –67 dBm.Recommended overlap between AP cells is 20 percent for VoWLAN networks. Access points on the same channel should have at least 19 dBm of signal separation. There are more channels in the 5-GHz band than in the 2.4-GHz band (23 in all), but all but nine channels are required to adhere to DFS and TPC.Because there are more channels in the 5-GHz band than in the 2.4-GHz band, the 5-GHz band is recommended for VoWLAN networks, to cut down on co-channel interference.VoWLAN networks will require more access points due to lower transmit power (25 mW) and higher data rates (24 Mb/s).

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Lesson 5

Conducting a Layer 2 Site Survey for 802.11n Clients

Overview When surveying with IEEE 802.11n access points, there are three modes of surveys that you can complete, depending on the type of client supported: greenfield mode, mixed mode, and legacy mode. The greenfield mode is known as the high-throughput mode and is for all devices that understand high-throughput mode (802.11n-capable). Mixed mode is a mixture of 802.11n-capable clients and non-802.11n-capable clients. Legacy mode means that there are no clients that understand 802.11n, just IEEE 802.11a/b/g.

When performing a survey in greenfield mode, an additional server is needed to run Iperf. AirMagnet Survey PRO uses this server to measure the physical data rates to and from the station (client).

Objectives Upon completing this lesson, you will be able to conduct a Layer 2 site survey for 802.11n clients using AirMagnet Survey PRO. This ability includes being able to meet these objectives:

Describe the recommendations for surveying in greenfield mode using Iperf

Describe where to download Iperf, and how to install and configure it

Describe how to configure AirMagnet Survey PRO to perform an active Iperf survey

Describe three types of surveys used when performing a survey with an 802.11n access point

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Active Survey with Iperf This topic describes the recommendations for surveying in greenfield mode using Iperf. AirMagnet provides the only survey solution that includes active site surveys and Iperf surveys so that the performance of an 802.11n end user can be measured and mapped.


802.11n and Site Surveys802.11n fundamentally changes WLAN survey methodology.

– MIMO and many other options are location-specific.– Turns multipath into a “good thing.”– End result: Signal strength is no longer an accurate predictor of

performance.802.11n requires active surveying.

– AirMagnet provides the only active surveying in the industry.– Latest release adds full Iperf functionality to actively test both

uplink and downlink performance:Allows you to get information about real PHY data rates, packet retries, and packet lossGet uplink (station-to-AP) and downlink (AP-to-station) information 802.11n performance will vary based on sender and receiverAP-to-station could be very different from station-to-AP

MIMO = mul tiple-input, multiple-output

When performing a survey for 802.11n, signal strength is not an accurate predictor of 802.11n performance. Multipath can actually enhance performance with 802.11n clients.

With active surveys, you can obtain information about real physical data rates, packet losses, and retries.

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Iperf Download and Installation This topic describes where to download Iperf and how to install and configure it. Before any configuration is done, you will need to download Iperf.


Installing Iperf ServerNavigate to http://www.noc.ucf.edu/Tools/Iperf/.– For Windows, select Local Download: iperf.exe (iperf version

1.7.0 (13 Mar 2003) win32 threads)– For other operating systems, select the appropriate download

link.Enter or browse to the desired extraction location on the hard drive and click Unzip to extract the files.It is recommended that you create an Iperf folder in the root directory to contain the files (such as C:\Iperf).

Iperf can be downloaded from the University of Central Florida at http://www.noc.ucf.edu/Tools/Iperf/.

The file that you want to download is iperf.exe (Iperf version 1.7.0 dated 13 March 2003). Versions for Windows, Sun Solaris, and Mac operating system X are available.

It is recommended that you create a folder called Iperf in the root directory. Unzip the iperf.exe file and put it in the C:\Iperf folder.

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To Start Iperf ServerChoose Start > Run to open the Run dialog box.Type ‘cmd’ and click OK to open the Windows command-line interface.Navigate to the Iperf folder (e.g., C:\Iperf) and type Iperf -p 5001 -s and press Enter. A message appears describing the TCP port in use by the server.

To start the Iperf server, navigate to the Iperf folder and type Iperf –p 5001 –s (where -p is the port and -s is server), then press Enter. AirMagnet uses port 5001 by default.

A message should appear indicating the TCP port that is in use by the server if the program starts correctly.

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Configuring AirMagnet for an Active Iperf Survey This topic describes how to configure AirMagnet Survey PRO to perform an active Iperf survey. Configure the access point and client for 40-MHz wide channels to improve throughput up to 300 Mb/s.


Active IPERF Survey Settings

To perform a greenfield (high throughput) survey (802.11n clients only), configure AirMagnet to perform an active IPERF survey. Select Active IPERF Survey from the Survey Type drop-down menu. Select an access point from the AP drop-down menu. Enter the IP address of the Iperf server that is running an active session of Iperf.

Click the Go button from the top right tool bar.

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Data Rate on the Uplink and Downlink

While surveying, watch the following:

Uplink data rate

Downlink data rate

Signal strength

Noise

Signal-to-noise ratio (SNR)

Percentage of packets lost

Percentage of packets retried

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Select 20 or 40 MHz for High ThroughputFile > Configure > PHY Data Rate Map > 80211n Channel Width > 40 MHz

If you are using the 5-GHz band, you can use 40-MHz channels to increase throughput. This is also known as 40-MHz high throughput. Channel bonding must be enabled on the client and the access point for 40-MHz high throughput.

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AP 40-MHz ChannelsNetwork Interfaces > Radio1-802.11N5GHz > Settings

Follow these steps to configure an access point to perform an active IPERF survey:

Step 1 Ensure that all modulation coding scheme (MCS) rates are enabled when surveying for 802.11n clients.

Step 2 Turn power down to at least half of what the 802.11n client supports.

Step 3 Select a channel that the client understands from the DefaultRadio Channel drop-down menu.

Note Remember, not all clients understand the UNII-2 extended channel set (for example, the Intel 4965 AGN client).

Step 4 Select above or below 40 MHz from the Channel Width drop-down menu.

Step 5 Scroll down and click Apply to apply these settings.

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Three Types of Surveys Using 802.11n Access Points

This topic describes three types of surveys used when performing a survey with an 802.11n access point. The 802.11 access points can support all 802.11a/b/g/n clients.


Three Survey ModesGreenfield mode – 5-GHz, 40-MHz wide channels (channel bonding)

up to 300 Mb/s– 2.4-GHz, 20-MHz wide channels up to 144.4 Mb/s– All clients are 802.11n-capable– High throughput format preamble

Mixed mode– A mixture of 802.11a/b/g/n clients

(Throughput will suffer for 802.11n-capable clients)Legacy mode– Legacy clients only 802.11a/b/g; no 802.11n clients– Throughput increased normally for 802.11a/b/g clients

Use the appropriate survey method for the client or clients supported:

Greenfield mode: This means no legacy 802.11 devices. All devices are 802.11n-capable. This means if you have legacy 802.11 devices in the facility, they would have to be removed. Otherwise, they cause interference, slowing down the 802.11n devices.

Mixed mode: Mixed mode supports both legacy devices 802.11a/b/g as well as 802.11n. This mode uses both a high-throughput preamble and a legacy preamble.

Legacy mode: Support for 802.11a/b/g clients, no 802.11n clients. All the same features as 802.11a/b/g: Ready to Send/Clear to Send (RTS/CTS), CTS to Self, Direct Sequence Spread Spectrum (DSSS), orthogonal frequency-division multiplexing (OFDM).

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SummaryWith 802.11n, signal strength is no longer an accurate predictor of performance, and 802.11n performance will vary based on the sender and receiver.When surveying for 802.11n, an Iperf server is used with AirMagnet Survey PRO to measure uplink and downlink data rates.When using the 5-GHz band for 802.11n, channel bonding can be turned on to increase throughput.There are three survey modes: greenfield mode, mixed mode, and legacy mode.

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Lesson 6

Conducting a Layer 2 Site Survey for Location

Overview A location site survey requires a different access point placement strategy. Access points should be placed in such a way that they surround the devices that they are tracking. You need a minimum of three access points, but four or more are recommended for good results. Normal access point separation is no more than 70 feet (21 meters).

Objectives Upon completing this lesson, you will be able to conduct a Layer 2 site survey for location services using AirMagnet Survey PRO. This ability includes being able to meet these objectives:

Describe the minimum signal level thresholds for location-aware WLAN design

Describe access point placement for location-aware WLAN design

Describe access point separation recommendations for location-aware WLAN design

Describe recommendations for a voice, data, and location-aware WLAN design

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Minimum Signal Level Thresholds This topic describes the minimum signal level thresholds for location-aware WLAN design. Location-aware devices must have a minimum signal level of –75 dBm.


Location Minimum Signal ThresholdsFor mobile devices to be tracked properly, you need the following:– A minimum of three access

points (four or more preferred)– –75 dBm RSSI for any device

being trackedDuring the site survey, if it is supporting location services, it must ensure that survey client does not exceed –72 dBm RSSI on the access point.

For mobile devices to be tracked properly, a minimum of three access points (with four or more preferred for better accuracy and precision) should be detecting and reporting the Received Signal Strength Indicator (RSSI) of any client station, asset tag, or rogue device being tracked. This detected signal strength level should be –75 dBm or better.

During the site survey, if it is supporting location-based services only (no data or voice), you must ensure that the surveyed client does not exceed –72 dBm RSSI on the access point. This will give you a 3-dB buffer from –75 dBm.

If you are surveying to add location-based services to an existing network, the following techniques can be used to verify the client signal strength:

View detected RSSI for the client or asset tag using the show client detail <mac address> or show rfid detail <mac address> controller command-line interface (CLI) command.

Using the location debug in Cisco Wireless Control System (WCS).

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Access Point Placement This topic describes access point placement for a location-aware WLAN design. Proper placement of access points is one of several best practices that should be adhered to in order to unleash the full performance potential of the location-aware Cisco Unified Wireless Network.


Access Point PlacementAccess points should surround the perimeter of the building as well as the interior of the building.When possible, mount antennas so that they have an unobstructed 360-degree view.

Access points supporting location-based services should surround the perimeter of a building as well as the interior, to track devices within the facility. When possible, mount antennas so that they have an unobstructed 360- degree view of the surrounding area.

Designs that use only clustered or straight-line access point placement should be augmented or redesigned in favor of those that combine center access point placement with perimeter and corner placement.

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Access Point Separation This topic describes access point separation recommendations for location-aware WLAN design. The distance between deployed access points can impact location performance as well as the performance of co-resident voice and data applications.


Access Point Separation Generally, access point separation for location should be between 40 and 70 feet (12 and 21 meters).– Access points should not be too close (28 feet [9 meters] or less).– Inter-access point placement may be closer than 40 feet due to

environments where high path loss is present.Antenna heights should not exceed 20 feet (6 meters). Cisco WCS considers the floor location ready if the following criteria is met:– At least four access points are deployed on the floor. – At least one access point is found to reside in each quadrant

surrounding the point in question. – At least one access point residing in each of at least three

of the surrounding quadrants is located within 70 feet of the point in question.

In general, most indoor location tracking deployments with access point antennas installed at heights of between ten and twenty feet can be well served with an inter-access point spacing of between 40 and 70 feet (12 and 21 meters). In some cases, however, inter-access point spacing below 40 feet may be necessary to satisfy the requirements of some applications for high signal strength thresholds, especially in environments where high path loss is present.

Cisco WCS considers the floor location ready if the following criteria is met:

At least four access points are deployed on the floor.

At least one access point is found to reside in each quadrant surrounding the point in question.

At least one access point residing in each of at least three of the surrounding quadrants is located within 70 feet of the point in question.

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AntennasThird-party antennas are not supported for:– Cisco WCS– Location appliance

Third-party antennas are not used for:– Heat map coverage– Location tracking for:

TagsClientsRogues

Cisco antennas are preloaded in Cisco WCS so that gain, direction, and antenna height can be managed.

When engineering an in-building WLAN solution, varying facility sizes, construction materials, and interior divisions can all raise concerns that must be considered during the design and deployment.

In the Cisco Unified Wireless Network, antennas available from Cisco are preconfigured in Cisco WCS and available for assignment to access points via the drop-down menus found by navigating to Monitor > Maps > Position APs. Selecting a Cisco antenna from this list automatically defines the gain and propagation patterns of the antenna to Cisco WCS and the location appliance, which helps facilitate optimal localization of tracked devices.

In some specialized cases however, there may be reasons to consider the use of third-party antennas that are not found on the Cisco WCS antenna list. These reasons may include the following:

Retrofit of a preexisting installation: If a preexisting standalone network is being upgraded to the controller-based solution, or if a preexisting installation is being upgraded, a large install base of third-party antennas is already deployed. Depending on their physical condition and their regulatory approval status for use with the latest IEEE 802.11 technologies, you may want to consider redeployment.

Specific Product Requirements: In some cases, a specific physical or electrical requirement of the design might dictate the use of a niche third-party antenna not contained on the Cisco WCS-supported list. For example, a fashion retailer may require the use of a zero-footprint antenna or an antenna available in a specific shape or color to augment the decor of a “Fifth Avenue” flagship retail location. Or an electronics manufacturing facility requires a directional antenna with a unique (and very specific) coverage pattern or polarization to better cover a specific area of the plant floor, while minimizing interference with sensitive equipment in a particular location.

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Cisco WCS allows for antenna gain to be specified for antennas that are not on the drop-down list of standard antennas. This can be performed using the Other antenna option.

Custom azimuth and elevation propagation patterns for Other third-party antennas cannot be defined in either Cisco WCS or the location appliance. Because of this, access points that are defined as being equipped with third-party antennas will not be included in coverage heat maps and will not participate in client, tag, or rogue on-demand location tracking.

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Location, Voice, and Data Coexistence This topic describes recommendations for a voice, data, and location-aware WLAN design. Location-based services can coexist with voice and data services if designed properly.


Location, Voice, and Data CoexistenceUse Cisco Aironet 1250 or 1240 Series dual-band access points.Design the voice WLAN on the 5-GHz band to support Cisco Unified Wireless IP Phones 7921G and 7925G handsets and high-speed client devices.Design the 2.4-GHz band for legacy voice and data devices as well as active RFID asset tags that are compatible with Cisco Compatible Extensions.–67 dBm cell edges.Reduced power radios to match coverage area for both 802.11b/g and 802.11a.Reduced power allows RRM capabilities.Survey for VoWLAN and then add any additional access points as monitoring access points to fill in for location services.

By using the Cisco Aironet 1250 or 1240 Series Access Points, you can accommodate 802.11a, 802.11b/g, or 802.11n devices with a full realm of services.

Design the WLAN to support Cisco Unified Wireless IP Phones 7921G and 7925G with high-speed clients on the 5-GHz (802.11a) WLAN. The 2.4-GHz (802.11b/g) operation is also supported, but due to the substantially reduced overall capacity on 802.11b/g brought about by the existence of only three noninterfering channels, its use is restricted to legacy data and voice devices, as well as active radio frequency identification (RFID) asset tags that are in compliance with Cisco Compatible Extensions for Wi-Fi tags specification. Legacy data devices would include devices that are unable to migrate to 802.11a for reasons such as that the client hardware device is no longer being offered for sale, battery life concerns, and so on.

Voice design models require –67 dBm cell edges for both 802.11a/n and 802.11b/g/n. Power should be reduced to incorporate equal cell size for both 802.11a/n and 802.11b/g/n. Cell overlap should be 20 percent for 802.11b/g/n cells and 15 to 20 percent for 802.11a/n cells.

Cisco Unified Wireless IP Phones 7921G and 7925G handsets have a maximum power of 40 mW. To ensure that Radio Resource Management (RRM) works correctly, the access point transmit power should be 25 mW or less. The RRM can be used to dynamically control access point transmit power based on real-time WLAN conditions. Under normal circumstances, the transmit power is maintained across all access points to maintain capacity and reduce interference.

If a failed access point is detected, the transmit power can be automatically increased on surrounding access points to fill the gap created by the loss in coverage.

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If a coverage hole occurs, RRM can use any remaining transmit power reserve on surrounding access points to raise the adjacent coverage levels and address the coverage hole until it can be investigated and resolved.

When the voice survey is complete, additional monitoring access points can be added to fill in corners and perimeter areas of the floor to ensure that the floor is location-ready.

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SummaryTracked devices should have a signal level of –75 dBm or greater.Access points deployed to perform location-based services should surround the device that it is to locate or track. Generally, access point separation for location services should be between 40 and 70 feet.

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Module Summary This topic summarizes the key points that were discussed in this module.


Module SummaryPlanning mode can predict access point count and placement, which is dependent on the data entered about the services supported.Cisco Spectrum Expert can identify interference by non-Wi-Fi devices in the 2.4- and 5-GHz spectrum.AirMagnet Survey PRO can perform pre-site surveys and post-installation site surveys.The 5-GHz band is recommended for VoWLAN networks to cut down on co-channel interference because there are more channels in the 5-GHz band than in the 2.4-GHz band.Generally, the access point separation for location-based services should be between 40 and 70 feet.

Predictive site surveys can be performed with the planning mode tool available in the Cisco Wireless Control System (WCS). By importing a floor map of the facility and entering criteria such as which wireless services will be supported (data, voice, location-based services), which access point is used, and the client density and throughput desired, Cisco WCS can take these values and generate an access point count, placement, and proposal report for the floor of the facility.

Before performing an active site survey for RF propagation and access point placement, a Layer 1 sweep should be performed with Cisco Spectrum Expert to ensure that the facility is free of other devices in the 2.4- and 5-GHz radio spectrum. Cisco Spectrum Expert has the capability to identify Bluetooth devices, cordless phones, baby monitors, wireless video cameras, and so on. Cisco Spectrum Expert can also identify RF jammers. If any of these devices are present at the facility, the Cisco Spectrum Expert Find utility can help locate these devices so that they may either be removed or replaced.

After a Layer 1 sweep with Cisco Spectrum Expert has been performed, a Layer 2 site survey can be performed with AirMagnet Survey PRO to determine the access point placement and coverage. AirMagnet Survey PRO has the capability of doing pre-site surveys (before the install) and post-site surveys (after the install), also known as an audit, to ensure adequate coverage. AirMagnet Survey PRO has the capability of providing much detailed survey information, such as Received Signal Strength Indicator (RSSI), signal-to-noise ratio (SNR), packet retries, and packet loss. When performing a site survey with AirMagnet Survey PRO, at least one active survey of each access point should be completed (two are recommended). When all active access point site surveys are completed, a passive site survey of the floor should be completed. These files should then be merged and results reviewed to ensure that the design criteria for the WLAN is met.

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Module Self-Check Use the questions here to review what you learned in this module. The correct answers and solutions are found in the Module Self-Check Answer Key.

Q1) Which of the following formats is not accepted for map import by Cisco WCS? (Source: Producing a Predictive Site Survey) A) PNG B) BMP C) JPG D) GIF

Q2) Which of the following represents a safety margin of safe? (Source: Producing a Predictive Site Survey) A) 0 dBm B) –3 dBm C) +3 dBm D) + 2 dBm

Q3) 0 dBm is equal to _____ in milliwatts. (Source: Conducting a Layer 1 Site Survey)

Q4) Cisco Spectrum Expert can display _____ different plots. (Source: Conducting a Layer 1 Site Survey)

Q5) How often are charts updated by the sensor? (Source: Conducting a Layer 1 Site Survey) A) every 10 seconds B) every 20 seconds C) every 30 seconds D) every 60 seconds

Q6) What is the maximum size of a spectrum recording .capture file? (Source: Conducting a Layer 1 Site Survey) A) 512 MB B) 1024 MB C) 1 GB D) size limit can be set up to 2 GB

Q7) Co-channel interference is worse than adjacent channel interference. (Source: Conducting a Layer 1 Site Survey) A) true B) false

Q8) Which tool does Cisco Spectrum Expert use to locate devices? (Source: Conducting a Layer 1 Site Survey)

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Q9) A warehouse stocked at 50 percent has a very different RF footprint than the same warehouse at an inventory level of 100 percent. (Source: Conducting a Layer 2 Site Survey for Data) A) true B) false

Q10) What are the two types of surveys that can be performed with AirMagnet Survey Pro? (Source: Conducting a Layer 2 Site Survey for Data)

Q11) When performing an active survey with AirMagnet, what is the default logging data period? (Source: Conducting a Layer 2 Site Survey for Data) A) one second B) two seconds C) three seconds D) four seconds

Q12) Cisco Aironet access points use short preamble.(Source: Conducting a Layer 2 Site Survey for Data) A) true B) false

Q13) What can be achieved when using 40-MHz wide channels while performing a 802.11a/n data survey in the 5-GHz band? (Source: Conducting a Layer 2 Site Survey for Data)

Q14) When performing a data site survey, you should survey with _____ percent overlap. (Source: Conducting a Layer 2 Site Survey for Data)

Q15) How many different types of reports can AirMagnet Survey PRO generate? (Source: Conducting a Layer 2 Site Survey for Data) A) eight B) nine C) ten D) eleven

Q16) What is the recommended cell overlap when performing a 2.4-GHz site survey for voice? (Source: Conducting a Layer 2 Site Survey for Voice Applications) A) 10 to 15 percent B) 15 percent C) 15 to 20 percent D) 20 percent

Q17) At 24 Mb/s, 802.11a and 802.11g can support up to _____ bidirectional RTP streams. (Source: Conducting a Layer 2 Site Survey for Voice Applications)

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Q18) When performing a voice site survey, what is the minimum recommended SNR? (Source: Conducting a Layer 2 Site Survey for Voice Applications) A) 24 dB B) 25 dB C) 26 dB D) 27 dB

Q19) For any device being tracked, what is the minimum receive signal level recommended? (Source: Conducting a Layer 2 Site Survey for Location)

Q20) Access points should be placed in the corners of a building when supporting location-based services. (Source: Conducting a Layer 2 Site Survey for Location) A) true B) false

Q21) When location-based services are to be supported on the WLAN, the antenna height should not exceed how many feet? (Source: Conducting a Layer 2 Site Survey for Location) A) 10 feet B) 20 feet C) 30 feet D) 40 feet

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Module Self-Check Answer Key Q1) B

Q2) A

Q3) one

Q4) five

Q5) B

Q6) A

Q7) B

Q8) Device Finder

Q9) A

Q10) active and passive

Q11) A

Q12) A

Q13) higher data rates

Q14) 10 to 15 percent

Q15) C

Q16) D

Q17) 27

Q18) B

Q19) –72 dBm

Q20) A

Q21) B

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Module 4

AP and Controller Density and Licensing

Overview This module describes infrastructure requirements, equipment, and licensing.

Module Objectives Upon completing this module, you will be able to determine the placement of the access points for data, voice, and location applications, as well as controller placement and redundancy. This ability includes being able to meet these objectives:

Determine the infrastructure requirements for the WLAN

Determine the number of access points, controllers, location appliances, and Cisco Wireless Control System licenses needed for the WLAN

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Lesson 1

Determining the Infrastructure Requirements for the WLAN

Overview This lesson describes WLAN power requirements, network access requirements, access point mounting requirements, and recommendations for adding access points to an existing WLAN to support voice-based or location-based services.

Objectives Upon completing this lesson, you will be able to determine the infrastructure requirements for the WLAN. This ability includes being able to meet these objectives:

Describe the power requirements for a WLAN deployment

Describe the current network infrastructure

Describe access point mounting considerations for a WLAN deployment

Describe the recommendations for adding additional access points to the WLAN deployment for voice or location-based services

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Power Requirements When deploying a WLAN, it is important to understand the various power options supported by Cisco access points, including Power over Ethernet (PoE) and IEEE 802.3af. Each access point has its own combination of power options and requirements. This topic describes the power requirements for a WLAN deployment


Power over EthernetIEEE 802.3af standardized PoECisco prestandard PoECisco enhanced PoE for 56-VDC powerPower sources– Cisco switches– Power injectors

PoE is the technology by which the LAN switching infrastructure provides power over a copper Ethernet cable to an endpoint (powered device). This technology, once referred to as inline power, was originally developed and first delivered by Cisco in 2000 to support emerging IP telephony deployments. IP telephones, like desktop PBX phones, need power for their operation and PoE enables scalable and manageable power delivery and simplifies deployments of IP telephony. As wireless networking emerged, PoE was also used to power these devices to allow for deployments in locations where local power access did not exist. While IP telephones and wireless access points are the most intuitive uses for PoE, the advent of 802.3af standardization of PoE opens the door to a new generation of networked devices such as video cameras, point-of-sale devices, security access control (card scanners), building automation, industrial automation, and so on.

Cisco offers a comprehensive range of 802.3af-based PoE support across its Cisco Catalyst intelligent switching portfolio with both 10/100/1000 and 10/100 PoE LAN connections, including a new 96-port 10/100 PoE module for the Catalyst 6500 Series Switches. Cisco recently introduced 802.3af-compliant PoE products that support the prestandard PoE implementation and are backwards-compatible with existing end devices from Cisco, such as IP phones and wireless access points. Additionally, Catalyst intelligent switches deliver intelligent power management capabilities beyond the optional IEEE power classification feature to enable granular, optimized, and scalable power delivery for more efficient power management and prioritization of power delivery.

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© 2009 Cisco Systems, Inc. AP and Controller Density and Licensing 4-5

PoE promises to create a new world of networked appliances by providing power as well as data connectivity over existing Ethernet cables.

The Cisco Aironet 1250 Series Access Point requires more power than allowed by the 802.3af standard. Certain Cisco Ethernet switches are capable of providing the greater amount of power and can fully power the Aironet 1250 Series Access Point with the RM1252 radio module installed. If an Ethernet switch with PoE is not being used, the power injector can be used for power.

The Cisco Aironet 1250 Series Access Point power injector combines 56-VDC power supplied by the external power supply with the data signal, sending both to the access point. The power injector provides up to 30 watts over the unused wire pairs of a Category 5 Ethernet cable, supplying enough power for a distance of 328 feet (100 meters).

A Category 5 Ethernet cable connects the power injector to a 10/100/1000 Ethernet switch, hub, or network, and another cable carries power and data to the access point or bridge Ethernet port. The power injector power supply connects to a wall outlet or power strip. The power injector can be mounted on most horizontal and vertical surfaces. However, they must not be stacked on top of each other.

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Power OptionsIEEE 802.3af inline power:– Cisco Aironet 1130AG Series– Cisco Aironet 1140AG Series– Cisco Aironet 1240AG Series

Cisco prestandard inline power:– Cisco Aironet 1130AG Series– Cisco Aironet 1240AG Series

Power injector required:– Cisco Aironet 1300 Series– Cisco Aironet 1400 Series

Local power module:– Cisco Aironet 1130AG Series – Cisco Aironet 1140AG Series – Cisco Aironet 1240AG Series– Cisco Aironet 1250AG Series

Cisco enhanced inline power 56 VDC– Cisco Aironet 1250AG Series

The table lists the power requirements of Cisco Aironet access points and bridges.

Access Points and Bridges Power Source

Cisco Aironet 1250 Series Access Point Inline power (Cisco enhanced 56 VDC)

Cisco Aironet 1130AG Series Access Point Inline power support (Cisco prestandard and 802.3af)

Cisco Aironet 1140AG Series Access Point Inline power support (802.3af)

Cisco Aironet 1300 Series Outdoor Access Point/Bridge

Inline power support (Cisco prestandard). Requires power injector LR2 style with two F connectors.

Cisco Aironet 1400 Series Outdoor Bridge Inline power support (Cisco prestandard). Requires power injector LR style with two F connectors.

Cisco Aironet 1500 Series Lightweight Outdoor Mesh Access Point

Inline power support: Requires Cisco Aironet 1500 Series power injector and Cisco Aironet 1500 Series outdoor Ethernet cable.

AC power: Cisco Aironet 1500 Series streetlight power tap.

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Power InjectorsPower injector– Cisco prestandard PoE– Cisco Aironet 1140AG, 1130AG, and

1240AG Series Access Points – New design provides enhanced

cable and device organizationPower injector media converter– Fiber uplink– Ideal for factories, warehouses, and

other large facilities with few wiring closets

– Support for alternative DC power source

– Certified for UL 2043 for installation in environmental air spaces

The single-port Cisco Aironet Power Injectors combine 48-VDC power with the data signal, sending both to the access point or bridge. The AIR-PWRINJ3 power injector for Cisco Aironet 1130AG, 1140AG, and 1240AG Series Access Points works with the power supply provided with the access point.

The Cisco Aironet Power Injector Media Converter (AIR-PWRINJ-FIB) converts fiber media to Category 5 media and combines the resulting data signal with power for delivery to the access point or bridge. The Aironet Power Injector Media Converter accepts 48-VDC power from either the barrel connector of the local power supply or an alternative 48-VDC power source. When powered by an alternate 48-VDC power source using the provided power supply pigtail, the Aironet Power Injector Media Converter is Underwriters Laboratories (UL) 2043-certified and suitable for installation in environmental air spaces. The local power supply is provided with the Cisco Aironet 1130AG, 1140AG, and 1240AG Series Access Points.

The AIR-PWRINJ-1000AF provides 802.13af inline PoE. It accepts 100–240 VAC and outputs 48 VDC.

The AIR-PWRINJ1500 power injector converts AC power into DC power and sends it along with the Ethernet signal to the access point. It is designed to be used with the Cisco Aironet 1500 Series Outdoor Ethernet Cable (AIR-ETH1500-150) to power the Cisco Aironet 1500 Series Lightweight Outdoor Mesh Access Point. Do not use any power injector other than the one specified to power the Cisco Aironet 1500 Series Mesh Access Point. The power injector is not 802.3af because of power requirements.

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Aironet 1250 Series Access Point Power Options

Power Injector– AIR-PWRINJ4– 56 VDC

Cisco-supplied DC power moduleSwitch with enhanced PoE

Switch (with or Without Inline Power)

Power Injector

Power Module

Access Point

The Aironet 1250 Series Access Point can receive power locally from the 1250 DC power module or from inline power using the Ethernet cable. The access point supports the 802.3af inline power standard. Using the inline power, you do not need to run a power cord to the access point because power is supplied over the Ethernet cable.

The access point supports the following power sources:

Cisco Aironet 1250 Series DC Power Module connected to the access point power connector

— The 1250 DC power module should be plugged into a 100–240 VAC source

Inline power:

— Cisco Aironet 1250 Series Power Injector

— 802.3af power source

Note The Cisco Aironet 1250 Series Power Injector is not suitable for operation in the environmental air space of a building and should not be installed in these environments.

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Cisco Enhanced PoE-Capable SwitchesCisco Catalyst 3750-E Series using 12.2(44)SE:– WS-C3750E-24PD-S – WS-C3750E-24PD-E – WS-C3750E-48PD-S – WS-C3750E-48PD-E – WS-C3750E-48PD-SF – WS-C3750E-48PD-EF

Cisco Catalyst 3560-E Series using 12.2(44)SE:– WS-C3560E-24PD-S – WS-C3560E-24PD-E – WS-C3560E-48PD-S– WS-C3560E-48PD-E– WS-C3560E-48PD-SF– WS-C3560E-48PD-EF

The following switches can provide 802.3af PoE for the Cisco Aironet 1250 Series Access Point when both radio modules are being used:

Cisco Catalyst 3750-E Series using 12.2 (44) SE:

— WS-C3750E-24PD-S

— WS-C3750E-24PD-E

— WS-C3750E-48PD-S

— WS-C3750E-48PD-E

— WS-C3750E-48PD-SF

— WS-C3750E-48PD-EF

Cisco Catalyst 3760-E Series using 12.2 (44) SE:

— WS-C3560E-24PD-S

— WS-C3560E-24PD-E

— WS-C3560E-48PD-S

— WS-C3560E-48PD-E

— WS-C3560E-48PD-SF

— WS-C3560E-48PD-EF

Cisco Catalyst 4000 Series Switches using 12.2(44)SG

Cisco Catalyst 4500-E Series linecards:

— WS-X4648-RJ45V-E

— WS-X4648-RJ45V+E

Cisco Catalyst 6000 Series using 12.2(33)SXH2

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Linecards:

— WS-X6148A-GE-45AF

— WS-X6148-GE-45AF

— WS-X6548-GE-45AF

— PoE daughter cards:

WS-F6K-48-AF

WS-F6K-GE48-AF

Note Some older switches and patch panels might not provide enough power to operate the access point. At power-up, if the access point is unable to detect sufficient power, the access point deactivates both radios to prevent an overcurrent condition, and the Status LED displays a low power error (cycles blue, green, red, and off).

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Evaluating the Current Network Infrastructure This topic describes the current network infrastructure. When designing a WLAN deployment, knowledge of the existing network infrastructure can help determine where the access points and controllers will be cabled into the existing wired network.


Where Will the Access Points Connect to the Network?

Are access points being placed within 328 feet of a wiring closet?If APs are Cisco Aironet 1250AG Series Access Points, are the switches 10/100/1000BASE-TX capable?Will new switches need to be added to support the installation?How will the APs receive power?– PoE-capable switch– Power injector– Power module

Where will the controllers be installed?

3750 Metro Series Switch

3750G WLAN Controller

When performing a site survey, you need to know where the existing infrastructure is and ensure that access point placement will not be impaired by cable lengths over 100 meters (328 feet) from their connection to the network.

A walk through the facility should be performed and the existing network evaluated to support the access point and controller deployment. These are some of the questions that should be answered.

If Cisco Aironet 1250AG Series Access Points are being deployed, will the network switches need to be upgraded to Cisco enhanced PoE-supported switches?

Are there enough gigabit ports (10/100/1000BASE-TX) on the infrastructure switches to support a Cisco Aironet 1250AG Series Access Point deployment?

If Cisco Aironet 1240AG Series Access Points are being deployed, will there be PoE available from existing switches or will power injectors be used?

If power injectors are to be used, are there enough AC outlets available in the wiring closets to support the number of access points being installed?

Where in the network will the controllers be placed?

Are gigabit switch ports available to connect the controllers to? The Cisco 4404 Series Wireless LAN Controller (WLC) with four Gigabit Ethernet ports supports up to 100 access points with link aggregation enabled.

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Mounting Considerations This topic describes access point mounting considerations for a WLAN deployment. The access point ships with an attached mounting plate and mounting hardware.


1240AG Series Access Point MountingMounting holes Mounting solutions:– Concrete– Drywall– I beam– Ceiling

Secure the APs

Access point mounting varies with the type of access point, its use, and the specific solutions that can be used in a particular environment. The access point can be mounted on any of the following surfaces:

Horizontal or vertical flat surfaces, such as walls or ceilings

Suspended ceilings (above and below)

Caution The access point, antennas, and the power source (power injector or power module) are not designed for outdoor use and must be located in an indoor environment.

The access point ships with a detachable mounting bracket and the necessary mounting hardware. Because it is detachable, the mounting bracket can be used as a template to mark the positions of the mounting holes for your installation. The engineer can install the mounting bracket and attach the access point when ready. The figure shows the location of the mounting holes on the bracket.

Note If you are mounting an access point with a 5-GHz radio in environmental air space, Cisco recommends that you mount the access point horizontally with its antennas pointing down. Doing so results in the access point complying with regulatory requirements for environmental air space.

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Note When mounting the access point in the environmental air space of a building, use Ethernet cable suitable for operation in such a space. Consult with Section 300-22(C) of the National Electrical Code (NEC).

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Mounting on a Horizontal or Vertical Surface

To mount an access point on a horizontal or vertical surface, follow these steps:

Step 1 Use the mounting bracket as a template to mark the locations of the four mounting holes.

Step 2 Drill one of the following sized holes at the locations that you marked:

3/16 inch (4.7 mm) if you are using wall anchors

1/8 inch (6.3 mm) if you are not using wall anchors

Step 3 Install the anchors into the wall if you are using them.

Step 4 Secure the mounting bracket to the surface using the fasteners.

Note On a vertical surface, mount the bracket with its security hasp facing down.

Step 5 Attach the access point to the mounting bracket.

Note You can make the installation more secure by mounting it to a stud or major structural member and using the appropriate fasteners.

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Mounting Below a Suspended Ceiling

To mount an access point on a suspended ceiling, follow these steps:

Step 1 Determine where to mount the access point.

Step 2 Attach two T-rail clips to the suspended-ceiling T-rail.

Step 3 Use the mounting bracket to adjust the distance between the T-rail clips so that they align with the holes in the mounting bracket.

Step 4 Use a standard screwdriver to tighten the T-rail clip studs in place on the suspended-ceiling T-rail. Do not over-tighten the clips.

Step 5 If you are using recessed ceiling tiles, install a plastic spacer on each T-rail clip stud. The spacer legs should contact the suspended-ceiling T-rail.

Step 6 Attach the mounting bracket to the T-rail clips studs and loosely install a Keps nut on each stud.

Step 7 Use a wrench or pliers to tighten the Keps nuts. Do not over-tighten.

Step 8 Attach the access point to the mounting bracket.

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Mounting Above a Suspended Ceiling

The access point mounting plate is designed to be integrated into the T-bar grid above the tiles of a suspended ceiling. Using a T-bar box hanger and bracket mounting clip (not supplied) such as the Erico Caddy Snap On Fixture/Box Hanger, orient the access point antenna just above the top surface of a standard ceiling tile. You may need to modify a thicker tile to allow room for the antenna.

Note Only the fiber-optic power injector (AIR-PWRINJ-FIB) has been tested to UL 2043 for operation in the environmental air space of a building; no other power injectors or power modules have been tested to UL 2043 and they should not be placed in an environmental air space, such as above suspended ceilings.

The bracket mounting clip requires the use of two mounting clip holes on the mounting plate.

Follow these steps to mount the access point above a suspended ceiling:

Step 1 Insert the tab of the bracket mounting clip into the large hole on the access point mounting plate.

Step 2 Place the clip over the T-bar box hanger and secure it to the access point mounting plate with the 1/4-20 fastener (supplied with the T-bar hanger).

Step 3 Determine the location in the ceiling where you will mount the access point and remove an adjacent ceiling tile.

Step 4 Orient the access point 2-GHz and 5-GHz antennas so that they are pointing down when mounted on the T-bar box hanger.

Step 5 Adjust the height of the T-bar box hanger to provide antenna clearance above the ceiling tile using the height adjusting screws.

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Step 6 Attach the T-rail clips on each end of the T-bar box hanger to the ceiling grid T-rails. Make sure the clips are securely attached to the T-rails.

Step 7 Connect a drop wire to a building structural element and through the hole provided in the bracket mounting clip. This additional support is required in order to comply with the U.S. NEC.

Step 8 Attach the access point to the mounting plate.

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Attaching the Access Point to the Mounting Bracket

If your mounting plate has the cable security bracket, follow these steps:

Step 1 Connect the Ethernet cable to the access point Ethernet port.

Step 2 If not using on-line power, connect the power cable of the power module to the access point 48-VDC connector.

Step 3 Carefully feed the Ethernet and power cables through the cable notch on the cable security bracket and slide the cables to the right or left to secure the cables.

Note If your access point is connected to Ethernet inline power, do not connect the local power module to the access point. Using two power sources on the access point might cause the access point to shut down to protect internal components and might cause the switch to shut down the port to which the access point is connected. If your access point shuts down, you must remove all power and reconnect only a single power source.

Step 4 Line up the four keyhole clips on the mounting plate with the large ends of the keyhole-shaped holes on the access point.

Note The keyhole clips on each side of the mounting plate are offset and can only be positioned in one direction onto the access point.

Step 5 Insert the mounting plate clips into the keyhole-shaped holes on the access point.

Step 6 Slide the access point towards the cable security bracket end of the mounting bracket while exerting slight pressure to force the access point and mounting plate together. You will hear a slight click when the locking detents contact the access point and lock it into place.

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Step 7 Attach and adjust the antennas or antenna cables to the access point antenna connectors.

Note The 5-GHz antennas and antenna cables have a blue dot or blue label. Connect only antennas or antenna cables with blue dots or labels to the access point 5-GHz antenna connector.

If your mounting plate does not have the cable security bracket, follow these steps:

Step 1 Connect a Category 5 Ethernet cable to the access point Ethernet port.

Step 2 If using local power, insert the power cable of the power module into the access point 48-VDC power port.

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Adding Additional Access Points This topic describes the recommendations for adding additional access points to the WLAN deployment for voice or location-based services. For optimum operation, a Cisco Unified Wireless IP Phone 7921G requires a signal level of –67 dBm or higher when using 2.4-GHz (802.11b and 802.11g) and the 5-GHz (802.11a), and signal-to-noise ratio (SNR) of 25 dB. In addition, maintain a packet error rate (PER) of no higher than 1 percent.


Adding Voice to a Data WLANDetermine if your WLAN is voice-ready

20 percent overlap, –67 dBm cell edges are needed to support voice.Use Cisco WCS to conduct a voice readiness test.Use the Cisco WCS planning tool to determine if you have the AP density to support a VoWLAN.If adding antennae, use diversity ceiling mount antennas.

To achieve maximum capacity and throughput, the WLAN should be designed to 24 Mb/s. Higher data rates (36 to 54 Mb/s) can optionally be enabled.

It is recommended that you set the minimum data rate to 11 Mb/s for 2.4 GHz and 6 Mb/s for 5 GHz, which should also be the only rate configured as a basic rate.

Adding capacity to the network is accomplished by using more access points on nonoverlapping channels. In the 2.4-GHz band, there are three nonoverlapping channels. However, on the 5-GHz (802.11a) band, all 23 channels (depending on geographic area) are nonoverlapping channels, which results in increased network capacity and the ability to deploy without interference from adjacent cells.

If you have Cisco Wireless Control System (WCS), you can run a voice readiness test. If it fails, use the Cisco WCS planning tool to see how many access points are needed to get the WLAN voice ready.

Access Point Antenna Selection Cisco recommends a diversity ceiling-mount antenna for voice applications. Ceiling-mounted antennas offer a quick and easy installation.

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More importantly, they place the radiating portion of the antenna in open space, which allows the most efficient signal propagation and reception. Cisco recommends that all antennas be placed one to two wavelengths from highly reflective surfaces such as metal. The 2.4-GHz wave is 4.92 inches (12.5 cm) and the 5-GHz wave is 2.36 inches (6 cm). The separation of one or more wavelengths between the antenna and reflective surfaces allows the access point radio a better opportunity to receive a transmission, and reduces the creation of nulls when the radio transmits. Orthogonal frequency-division multiplexing (OFDM), used by IEEE 802.11g and 802.11a, helps to mitigate problems with reflections, nulls, and multipath; however, good antenna placement and the use of appropriate antenna types provide a superior solution. The ceiling tile itself is a good absorber of signals transmitted into the area above the ceiling and reflected back into the coverage area.

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Adding Location Services to your WLANMonitoring APs will need to be addedEnable LOMM on 2.4-GHz APs Inspect location readiness with Cisco WCSUsing the monitor mode APs can help location implementationsAfter implementation, calibration function available within Cisco WCS should be utilized to ensure higher location accuracy

To optimize the monitoring and location calculation of radio frequency identification (RFID) tags, you can enable location optimized monitor mode (LOMM) on up to four channels within the 2.4-GHz band of an 802.11b/g access point radio. This feature allows you to scan only the channels on which tags are usually programmed to operate, such as channels 1, 6, and 11.

To configure LOMM on the access point, follow these steps:

Step 1 Navigate to Wireless > Access Points > All APs to open the All APs page.

Step 2 Click the name of the access point for which you want to configure monitor mode. The Details page appears.

Step 3 From the AP Mode drop-down menu, choose Monitor.

Step 4 Click Apply to commit your changes.

Step 5 Click OK when warned that the access point will be rebooted.

Step 6 Click Save Configuration to save your changes.

Step 7 Navigate to Wireless > Access Points > Radios > 802.11b/g/n to open the 802.11b/g/n Radios page.

Step 8 Position the mouse over the blue drop-down arrow for the desired access point and click Configure. The 802.11b/g/n Cisco APs > Configure page appears.

Step 9 To disable the access point radio, choose Disable from the Admin Status drop-down list and click Apply.

Step 10 To enable LOMM on the radio, choose Enable from the LOMM Enable drop-down list.

Step 11 From the four Channel drop-down lists, choose the channels on which you want to monitor RFID tags.

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Note You must configure at least one channel on which the tags will be monitored.

Step 12 Click Apply to commit your changes.


Step 14 To re-enable the access point radio, choose Enable from the Admin Status drop-down list and click Apply.


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SummaryCisco access points accept different types of PoE. Not all Cisco access points accept 802.3af.Existing network infrastructure should be inspected to see if infrastructure upgrades are required to support the proposed WLAN. Cisco Aironet access points come with mounting hardware. Additional access points may be needed to support VoWLAN or location-based services.

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Lesson 2

Determining the WLAN Equipment and Licenses

Overview This lesson describes access point and controller density and redundancy for a WLAN. The lesson also describes density and licensing for the Cisco Wireless Control System (WCS), Cisco 3300 Series Mobility Services Engine (MSE), and the location server.

Objectives Upon completing this lesson, you will be able to determine the number of access points, controllers, location appliances, and Cisco WCS licenses needed for the WLAN. This ability includes being able to meet these objectives:

Determine the number of access points and controllers needed for a WLAN deployment

Determine the Cisco WCS licenses and number of location servers or MSE needed for a WLAN deployment

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Controllers and Access Points This topic describes the number of access points and controllers needed for a WLAN deployment. With the Cisco WCS database, you can add maps and view your managed system on realistic campus, building, and floor map maps.


Access Point Density802.11a/b/g/n client densityTypically 15 to 25 users per radioDepends on WLAN services supported and the number of wireless users that will access the network

Data-only WLANs require density based on the number of users and expected throughput. If you plan to add voice, you will need to increase the number of access points. When surveying any network, the first priority is to determine the user needs. For a WLAN, this includes defining the coverage area and what the customer needs. You need to determine whether users need specialty devices on the WLAN, such as bar code readers, wireless IP phones, or wireless printers, and the minimum speeds or bandwidth that users require. You need to determine how many users will be in a given area. For the average office application, you can get reasonable performance with 15 to 25 users per access point when using 802.11 data rates. For an application such as bar code reading, the number of users can increase considerably and this may require using IEEE 802.11g to increase data rates.

If the need exists to effectively support 802.11a and 802.11g users, especially when there are many active users, you should consider a dual-mode access point. Dual-mode access points provide separate 802.11a and 802.11g radios in the access points that are set to different, nonoverlapping RF channels.

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A significant advantage of 802.11a is that it offers very high capacity compared to the other standards, and it operates in the 5-GHz band, which is mostly free from sources of RF interference. The 5-GHz spectrum provides the most flexible method of high bandwidth design because there are 21 channels available in the 5-GHz spectrum. These channels do not have frequency overlap as is the case with the 2.4-GHz spectrum. Therefore 21 access points could share the same floor space and not interfere with each other or with the clients associated to them when in 5-GHz 802.11a mode. Microwave ovens and Bluetooth devices operate in the 2.4-GHz band. However, the disadvantage of 802.11a is that the standard has limited regulatory acceptance around the world. The IEEE working group is actively working on 802.11n, but it has not been ratified. However, products based on the draft version of the standard are already being sold.

The 802.11a standard will be the basis of the next generation of WLANs, with data rates well above 100 Mb/s and providing both 2.4-GHz and 5-GHz radio modules. The 5-GHz 802.11n wide channel mode (40 MHz) provides for nine nonoverlapping channels. When standard 20 MHz wide channels in the 5-GHz 802.11n band are used, there are 21 nonoverlapping channels like 802.11a. The 802.11n specification raises expectations of improved cell throughput, capacity, and coverage, but an 802.11b client is still an 802.11b client, even when a client is associated to an 802.11n-enabled access point. The 802.11b client still has a maximum data rate of 11 Mb/s per second and a maximum throughput of 7.1 Mb/s. The coverage of the access point may be improved by the increased receiver sensitivity and increased transmit power, but the improvement is likely to be no more than ten percent.

Cisco Aironet 1130AG and 1240AG Series Access Points are dual-mode access points. With dual 802.11a and 802.11g radios, the access point provides up to 108 Mb/s of capacity in a single device. The Cisco Aironet 1250 Series Access Point supports 10/100/1000 Ethernet, which was specifically engineered to support the power, throughput, and 802.11n.

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Access Point Density with LocationDesign and deployment considerations should be followed as a starting point Adherence to an inter-access point separation of 40 to 70 feet

Proper placement of access points is critical if the system is expected to fully deliver on its performance potential. In many office WLANs, access points are distributed throughout interior spaces, providing more than adequate coverage to surrounding work areas. These locations are usually selected on the basis of coverage, WLAN bandwidth, channel reuse, cell-to-cell overlap, security, aesthetics, and deployment feasibility. In a location-aware WLAN design, however, access points must not be located based solely on these criteria but must strike a balance between these criteria and location placement requirements. Although there is no single rule that consistently yields the proper access point density for every environment, the signal threshold and placement suggestions made in the Wi-Fi Location-Based Services 4.1 Design Guide by Cisco should be considered. Design and deployment considerations should be followed as a starting point of any location-aware design. Among these recommendations is the adherence to an inter-access point separation of between 40 to 70 feet.

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Access Point Density by Data Rate Supported

By increasing the access point count and lowering the power, you can improve throughput for users. The type of services offered, such as VoWLAN and location-aware WLAN, will increase the number of access points needed for these services to operate correctly.

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Access Point Density Generated by Cisco WCS Planning Tool

The Cisco WCS Planning Mode window enables you to calculate the number of access points required to cover an area by placing fictitious access points on a map and allowing you to view the coverage area. Based on the throughput specified for each protocol (802.11a/n or 802.11b/g/n), planning mode calculates the total number of access points required to provide optimum coverage in your network. You can calculate the recommended number and location of access points based on the following criteria:

Traffic type active on the network: data or voice traffic or both

Location accuracy requirements

Number of active users

Number of users per square footage

The recommended number of access points given the selected services appears.

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Controller Access Point DensityCisco 2106 WLC: 6 APs Cisco 2112 WLC: 12 APsCisco 2125 WLC: 25 APsCisco 4402 WLC: 12, 25, 50 APsCisco 4404 WLC: 100 APsCisco Catalyst 6500 Series WiSM: 300 APs

4404 Series controller

2100 Series WLC

Cisco Catalyst 6500 Series WiSM

Several options of WLAN controllers are available, supporting as few as six access points to as many as 300 access points.

The Cisco 2100 Series WLCs are designed for enterprise branches and small and medium-sized businesses. The Cisco 2106 WLC supports up to six access points and comes with eight Ethernet ports, two of which can provide power to Cisco access points. The Cisco 2112 WLC supports up to 12 access points and comes with eight Ethernet ports, two of which can provide power to access points. The Cisco 2125 WLC supports up to 25 access points and comes with eight Ethernet ports, two of which can provide power to access points.

The Cisco 4400 Series WLC is available in two models: The Cisco 4402 WLC with two Gigabit Ethernet ports, which comes in configurations that support 12, 25, and 50 access points, and the Cisco 4404 WLC with four Gigabit Ethernet ports supports 100 access points.

As a member of the Cisco WLC family, the Cisco Catalyst 6500 Wireless Services Module (WiSM) works in conjunction with Cisco access points and the Cisco WCS to support mission-critical wireless data, voice, and video applications. As a key component of Cisco Unified Wireless Network for the enterprise, and Cisco service mesh architecture for service providers, the Cisco WiSM provides real-time communication between access points and other controllers to deliver a secure, end-to-end wireless solution.

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N + 1 Redundancy Design In the N + 1 redundancy configuration, one controller backs up n controllers.


Deterministic Redundancy Designs: N + 1

In this configuration, the redundant controller is placed in the network operations center (NOC) or data center and acts as a backup for multiple controllers. Each access point is configured with a primary controller and all access points point to the next single redundant controller as secondary.

One issue with this design is that the redundant controller could become oversubscribed with access points if there are multiple primary controller failures, which is usually unlikely. When a controller reaches the maximum number of joined access points, it accepts no more Lightweight Access Point Protocol (LWAPP) join requests. When the backup controller becomes oversubscribed, some access points could be without a controller. When designing an N + 1 redundant solution, you should assess the risks of multiple controller failures and the consequences of an oversubscribed backup controller.

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N + N Redundancy Design In the N + N redundancy configuration, N controllers back up N controllers.


Deterministic Redundancy Designs: N + N

In the figure, there are two controllers. Some of the access points are configured with Controller-A as its primary and Controller-B as secondary, while other access points are configured with Controller-B as primary and Controller-A as secondary.

In this design, it is important to load-balance the access point capacity across both controllers. It is also important to try to logically group access points on controllers to minimize inter-controller roaming events. For example, if you are supporting a four-floor building with two redundant controllers, you might configure the access points on floors one and two to use one controller as primary and the access points on floors three and four to use the other controller as primary.

Note There should be enough access point and bandwidth capacity on each controller to handle a failover situation.

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N + N + 1 Redundancy Design In the N + N + 1 redundancy configuration, N controllers back up N controllers as secondary, and one controller backs up all N controllers as tertiary.


Deterministic Redundancy Designs: N + N + 1

In the figure, some of the access points are configured with Controller-A as primary and Controller-B as secondary, and some of the access points are configured with Controller-B as primary and Controller-A as secondary. All of the access points are configured to use the same backup as tertiary. Typically, the primary and secondary controllers are placed at the network distribution level and the tertiary controller is placed in an NOC or data center. Multiple distribution blocks can be configured with the same tertiary controller.

When selecting a redundancy option, you should consider the risk of controller failure and the service level agreement (SLA) required. The higher the SLA, the more robust a redundancy scheme your designed solution should provide.

Cisco Unified Wireless Network Software Release 5.1 now allows for the plus one controller at the NOC or data center to no longer have to be a member of the same mobility group. It can now be referenced by its IP address versus being part of the same mobility group.

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Cisco WCS Licenses for Location Servers and the MSE

This topic describes how to determine the Cisco WCS licenses and number of location servers or MSE needed for a WLAN deployment. Cisco WCS base supports standard Cisco WCS capabilities. Cisco WCS location includes all base features plus the ability to track a single Wi-Fi device on demand or expand location capabilities by adding a Cisco Wireless Location Appliance or the MSE with context-aware software, to simultaneously track multiple Wi-Fi devices.


Cisco WCS Access Point DensityHigh-end server– Access points

Up to 3000 Cisco lightweight APs1250 autonomous APs

– 750 controllers– Intel Xeon Quad 3.16-GHz CPU with 8-GB RAM– 200-GB HDD

80 GB minimum free disk space on the hard driveNote: The free disk space listed is a minimum requirement but may be different for your system, depending on the number of backups.

The following requirements must be met for a high-end server:

Up to 3000 Cisco lightweight access points, 1250 autonomous access points, and 750 Cisco controllers

Intel Xeon Quad 3.16-GHz CPU with 8-GB RAM

80 GB minimum free disk space on your hard drive

Note The free disk space listed is a minimum requirement but may be different for your system, depending on the number of backups.

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Cisco WCS Access Point Density (Cont.)Standard server

Access points– Up to 2000 Cisco lightweight APs– 1000 autonomous APs

450 controllers Intel Dual Core 3.2-GHz CPU, 4 GB RAM80-GB HDD – 40 GB minimum free disk space on the hard drive

The following requirements must be met for a standard server.

Up to 2000 Cisco lightweight access points, 450 Cisco controllers, and 1000 autonomous access points

Intel Dual Core 3.2-GHz CPU with 4-GB RAM


— 40-GB HDD

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Cisco WCS Access Point Density (Cont.)Low-end server

Access points– Up to 500 Cisco lightweight APs– 200 autonomous APs

125 controllers Intel 3.06-GHz CPU, 2 GB RAM– 40-GB HDD

30 GB minimum free disk space on your hard driveOperating systems supported– Microsoft Windows 2003, SP 2, 32- and 64-bit– Red Hat Linux Enterprise Server 5.0 or 5.1, 32- and 64-bit

The following requirements must be met for a low-end server.

Up to 500 Cisco lightweight access points, 200 autonomous access points, and 125 Cisco controllers.

Intel 3.06-GHz CPU, 2-GB RAM


— 40-GB HDD

Supported Operating Systems Depending on the number of access points supported, Cisco WCS has the following minimum operating system requirements:

Microsoft Windows 2003, Service Pack 2, and Windows 2003 R2 with SP2, 32-bit installations with all critical and security Windows updates installed

Microsoft Windows 2003, Service Pack 2, 64-bit installations not supported

Microsoft Windows 2003, 32-bit installations provide support for up to 64 GB of RAM if Physical Address Extension (PAE) is enabled.

Red Hat Linux Enterprise Server 5.0 or 5.1, 32-bit installation operating system

Red Hat Linux Enterprise Server 5.0 or 5.1, 64-bit installation operating system is not supported.

Windows 2003 and Red Hat Linux version support on VmWare ESX 3.0.1 version and later.

Individual operating systems running Cisco WCS in VmWare must follow the specifications for the size of Cisco WCS that you intend to use.

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Mobility and Location Server Client Density

AIR-MSE-3350-K9-Cisco 3350 MSE Up to 18,000 clients and tags for contextual informationCisco 2700 Series applianceUp to 2500 clients and tags

The Cisco 3350 MSE hosts the Cisco context-aware software. Cisco Context-Aware Software allows for the tracking of up to 18,000 clients and tags for contextual information. Separate licensees are required for Context-Aware Software for clients and Context-Aware Software for tags.

The location appliance tracks 802.11 devices directly from a WLAN infrastructure using advanced RF fingerprinting technology. Additionally, the appliance records information so that you can establish location trends and resolve problems regarding radio RF capacity.

By design, the location appliance is directly integrated into the WLAN infrastructure and is configured through its command-line interface (CLI) and then managed through Cisco WCS. The location appliance tracks the physical location of wireless devices using controllers and controller-based access points. This appliance tracks any Wi-Fi device, including Wi-Fi clients, standards-based Wi-Fi active RFID tags, rogue access points, and clients. It was designed with the following requirements in mind:

Manageability: The same browser-based interface that is used for the Cisco WCS is also used for the appliance. Moreover, the location appliance integrates directly into the WLAN architecture, providing one unified network to manage instead of multiple disparate wireless networks.

Scalability: The appliance was built to simultaneously track up to 2500 wireless devices. Cisco WCS can manage multiple location appliances for greater scalability.

Security: The controller, Cisco WCS, and the location appliance were separated to deliver the most secure architecture possible. The appliance records historical location information that can be used for audit trails and regulatory compliance.

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Open and standards based: The appliance has a Simple Object Access Protocol/Extensible Markup Language (SOAP/XML) application programming interface (API) that can be integrated by partners with other business applications and can track any standards.

Easy deployment of business applications: The appliance can be integrated with new business applications such as asset tracking, inventory management, location-based security, or automated workflow management.

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LicensingThe following products require licensing– Cisco WCS

Licenses are based on access point count– Cisco 2700 Series Wireless Location Appliance– Cisco 3550 Series Mobility Services Engine

Licenses are based on user count

Before you purchase a Cisco WCS license, determine if you will need a Base or Location license and how many access points will need to be supported and licensed.

The two types of Cisco WCS support different feature levels:

Cisco WCS Base: Cisco WCS Base supports standard Cisco WCS capabilities, which includes wireless client data access, rogue access point containment functions, Cisco WLAN Solution monitoring and control, and client and rogue access point location to the nearest access point.

Cisco WCS Location: Cisco WCS Location includes all the features present in the Cisco WCS Base, plus the ability to track a single Wi-Fi device on demand or expand location capabilities by adding a Cisco Wireless Location Appliance to simultaneously track up to 2500 Wi-Fi devices.

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Mobility Services Engine Licensing AIR-CAS-3KC-K9: License for tracking 3000 client devicesAIR-CAS-6KC-K9: License for tracking 6000 client devicesAIR-CAS-12KC-K9: License for tracking 12,000 client devicesAIR-CAS-3KT-K9: License for tracking 3000 tag devicesAIR-CAS-6KT-K9: License for tracking 6000 tag devicesAIR-CAS-12KT-K9: License for tracking 12,000 tag devices

The Cisco 3300 Series Mobility Services Engine is an open platform that provides a new approach for the delivery of mobility services to enable mobile business applications. A combination of hardware and software, the MSE is an appliance-based solution that supports a suite of software services to provide centralized and scalable service delivery. Cisco Mobility Services are a set of value-added network services that consolidate intelligence from various points in the network to enable and optimize the delivery of business mobility applications. The Cisco Context-Aware Mobility Software is a mobility service and integrates with the Cisco Unified Wireless Network to capture and integrate into business processes detailed contextual information such as location, temperature, availability, and applications used.

The Cisco MSE hosts the Cisco Context-Aware Software. Cisco Context-Aware Software allows for the tracking of up to 18,000 clients and tags for contextual information. Separate licenses are required for Context-Aware Software for clients and Context-Aware Software for tags.

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SummaryAccess point density is determined by number of users to be supported and wireless services to be rendered. Controller density is determined by access point count and redundancy model chosen. Client density and licensing for location or MSE are determined by the number of clients and tags that are to be supported. Cisco WCS licensing is determined by the number of access points supported.

References For additional information, refer to these resources:

http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/WiFiLBS-DG.html

http://www.cisco.com/en/US/products/ps6305/products_data_sheet0900aecd804b4646.html

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Module SummaryInline power for access points can be Cisco prestandard, IEEE 802.3af, or Cisco Enhanced PoE, depending on access points deployed.It is important that you validate existing network infrastructure for power and switch port availability for access point and controller deployment. Cisco APs are sold with mounting brackets that can be wall mounted vertically or ceiling tile mounted horizontally.If a WLAN is to be upgraded or implemented to support voice, ensure that the –67 dBm cell radius and the 20 percent recommended cell overlap is achieved. In addition, you should use the 802.11a network rather than the 802.11g network for less noise and better separation of channels.Access point density is determined by the number of users and wireless services to be supported.Controller density is determined by access point count and redundancy model chosen.Client density and licensing for location and MSE is determined by the number of supported clients and tags.Cisco WCS licensing is determined by the number of supported access points.

Different Cisco access points have different Power over Ethernet (PoE) requirements. Some access points accept Cisco prestandard PoE, which means that the access point receives its power from a Cisco inline-power-capable switch. The Cisco Aironet 1240AG and 1130AG Series Access Points can be powered from either Cisco prestandard PoE or IEEE 802.3af PoE. If you wish to power both radios on the Aironet 1250 Series Access Point, you will need a 56-VDC power injector or switch from Cisco that is capable of providing the additional voltage and amperage required. Cisco Enhanced PoE is available on some Cisco switches.

When overlaying a WLAN over an existing network infrastructure, you should check to see if there is port availability on the existing network switches to accommodate the Cisco access points and controllers. The Cisco 4400 and 4404 Series WLCs require Gigabit Ethernet connections. The Cisco Aironet 1250 Series Access Points need Gigabit Ethernet connections as well. Adding Voice over wireless LAN (VoWLAN) to an existing data WLAN can be difficult if the WLAN was not originally designed for voice. VoWLAN is more demanding and less tolerant of dropped packets and latency. Lower power, higher data rates, and twenty percent overlap are some of the recommendations.

Wireless client density and wireless applications drive network design for access point density. Access point density and controller redundancy drive the design for the number of controllers required for the WLAN. Cisco Wireless Control System (WCS) licensing depends on the type of network services currently running and the access point count.

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Q1) What wattage does Enhanced PoE supply to the Cisco Aironet 1250 Series AP? (Source: Determining the Infrastructure Requirements for the WLAN) A) 15.4 watts B) 16.8 watts C) 18.5 watts D) 20.5 watts

Q2) What wattage does the Cisco Aironet 1242AG Series AP operate on? (Source: Determining the Infrastructure Requirements for the WLAN) A) 15.4 watts B) 16.8 watts C) 18.5 watts D) 20.5 watts

Q3) What port speeds does Cisco Aironet 1250AG Series AP support? (Source: Determining the Infrastructure Requirements for the WLAN)

Q4) Cell edges should be _____ dBm when designing the WLAN to support VoWLAN in UNII-1 and UNII-3 bands. (Source: Determining the Infrastructure Requirements for the WLAN)

Q5) What does LOMM stand for? (Source: Determining the Infrastructure Requirements for the WLAN) A) location optimized monitor mode B) location optional monitor mode C) location operational monitor mode D) location optimum monitor mode

Q6) What is the recommended cell overlap when designing a WLAN for voice? (Source: Determining the Infrastructure Requirements for the WLAN) A) 10 percent B) 15 percent C) 20 percent D) 25 percent

Q7) Cisco recommends using ceiling-mounted omnidirectional diversity antennas when designing VoWLANs. (Source: Determining the Infrastructure Requirements for the WLAN) A) true B) false

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Q8) How many access points can Cisco Catalyst 6500 Series WiSM support? (Source: Determining the WLAN Equipment and Licenses) A) 100 B) 150 C) 200 D) 300

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Module Self-Check Answer Key Q1) C

Q2) A

Q3) 10/100/1000

Q4) –67

Q5) A

Q6) C

Q7) A

Q8) D

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Module 5

Assessment of the Deployment

Overview When installation of the WLAN is completed, including IP addressing and configuration, verification of coverage must be completed. If Voice over wireless LAN (VoWLAN) was installed, then extensive testing must be completed to verify that VoWLAN services are working properly. All services installed must be tested completely to ensure that they are working properly. All installation devices, IP addressing, and network configurations should be documented and included in an installation report.

Module Objectives Upon completing this module, you will be able to assess the deployment of the WLAN. This ability includes being able to meet these objectives:

Describe the steps necessary to verify RF coverage of the deployment and make necessary adjustments

Describe the steps necessary to use the Cisco WCS tools to verify the readiness of the WLAN to support the desired applications

Describe the information needed in an installation report

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Lesson 1

Verifying RF Coverage

Overview Before a WLAN can go live, you should perform an application verification. During this phase, you complete final access point or antenna adjustments that are necessary to optimize the WLAN. You should test applications such as location tracking and Voice over WLAN (VoWLAN) to ensure that they are working properly.

Objectives Upon completing this lesson, you will be able to describe the steps necessary to verify RF coverage of a deployment and make necessary adjustments. This ability includes being able to meet these objectives:

Describe how to perform an RF audit using AirMagnet Survey PRO

Describe how to tune the Radio Resource Management parameters for the deployed WLAN

Describe how to tune various network appliances deployed in the WLAN

Describe how to verify the applications using the local client

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RF Audit This topic describes how to perform an RF audit using AirMagnet Survey PRO. Post-installation surveys are conducted on existing WLAN sites. The goal is to validate or audit the current WLAN deployment in order to enhance its security and performance. Unlike preinstallation site surveys, postinstallation surveys focus more on the entire site environment.


Postinstallation Audit with AirMagnetConduct a passive survey of the entire deployment area: – Conduct a separate passive survey per

media type, IEEE 802.11a, 802.11b, 802.11g, 802.11n.

– Check for co-channel interference.– Ensure that all access points installed

are working.– Check to ensure you have adequate

signal levels as surveyed.– Compare the coverage and data rates of

the postinstallation survey with the survey that was performed prior to the installation.

Post-installation survey procedures can be summarized as follows:

Conduct a passive survey of the entire deployed environment (divided into several shorter surveys, if necessary) and compare the results to those generated during the planning stage of the predeployment process.

Make any required adjustments that were not accounted for in the preinstallation portion in order to make the network meet user and throughput requirements.

Conduct a separate passive site survey for each media type supported (IEEE 802.11a, 802.11b, 802.11g, or 802.11n). Check for co-channel interference by standing near an access point on one channel and watch for other access points that are on the same channel. Check to see if the signal level on other access points heard on the same channel is at least 19 dBm weaker than the access point that you are next to.

When you have completed the post-installation surveys, compare them to the surveys that were performed prior to the installation. They should look nearly identical.

Check Cisco Wireless Control System (WCS) to verify that all access points installed show up in the access point list.

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© 2009 Cisco Systems, Inc. Assessment of the Deployment 5-5


Postinstallation Audit with AirMagnet (Cont.)

Conduct an active survey with AirMagnet Survey PRO:– Perform a separate active survey by

media type.– Survey by SSID to ensure that roaming is

taking place.– Set roaming criteria.– For 802.11n active surveys, use Iperf to

verify up and down link speeds.

Additional postinstallation survey procedures are as follows:

Conduct an active survey with AirMagnet Survey PRO in order to verify that there are no gaps in the coverage area that were not discovered during the passive survey. This process also allows you to verify that the real-world network traffic (for example, physical data rate, packet loss or packet retry, uplink or downlink data) meets user requirements.

Perform a separate active site survey for each media type supported (802.11a, 802.11b, 802.11g, or 802.11n). Survey by Service Set Identifier (SSID) to ensure that smooth roaming is taking place. Walk both sides of all access points to ensure that you stay connected.

Roaming Control The Roaming Option button in the top right of the active survey window allows you to control the roaming status of your network adapter. It can help define precisely when your card will roam, based on several different values. Click the Roaming Option button to open the Set Roaming Criteria dialog box.

You may now adjust roaming values to determine when the adapter begins to roam. It is important to note that this roaming configuration takes place within AirMagnet Survey; the settings do not extend to your Windows network configuration.

Roaming will trigger when any one of these values is met. Configuring roaming based on signal strength will cause your computer to roam when it reaches specific minimum signal strength, whereas speed will cause it to roam once a minimum transmission speed is met. Max retries refers to the number of times the computer has to re-send lost data to the access point.

The roaming control option will only work with the following wireless adapters:

3Com 802.11a/b/g Wireless PC Card (3CRPAG175 and 3CRPAG175B)

AirMagnet Trio 802.11a/b/g wireless adapter (NL-5354CB ARIES)

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Wireless CardBus Adapter Super A/G (NL-5354CB PLUS Aries2 and NL-5354 B PLUS Aries2-F)

AirMagnet 802.11a/b/g Wireless LAN Mini PCI Adapter

Buffalo AirStation WLI-CB-AMG54 wireless adapter (For Japan only)

Cisco 802.11a/b/g Wireless Adapter AIR-CB21AG

Enterasys a/b/g RoamAbout CB-500AG

LANCOM Systems Airlancer 54-ag

Linksys Wireless A+G Notebook Adapter WPC55AG version 1.2 and 1.3

Netgear WAG511 802.11 a/b/g wireless adapter, WAG511v2 802.11 a/b/g, and WG511U Double 108 Mb/s wireless adapter

Nortel Networks 802.11 a/b/g wireless adapter 2202

OQO Model O2 UMPC (Atheros tri-mode 802.11 a/b/g)

Proxim ORiNOCO 802.11 a/b/g ComboCard Gold (8480-XX) and ORiNOCO 802.11 b/g PC Card Gold (8470-XX)

TRENDnet 802.11 a/g Wireless CardBus PC Card (TEW 501 PC)

Ubiquiti SRC 802.11 a/b/g MMCX adapter

For 802.11n media types, enable Iperf on a server and assign the IP address of the server in the Iperf active survey window within AirMagnet Survey PRO. This will allow you to check the uplink and downlink speeds when performing your active survey for 802.11n clients.

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Tips for Improved AirMagnet Survey Accuracy

Focus on one band (2.4 or 5 GHz) at a time.Plan the survey path ahead of time.Be sure to survey from all areas of the network.Moving too quickly can result in insufficient data.Moving too slowly results in longer processing times due to an excess of gathered information.Active rather than passive surveys give a more comprehensive perspective of real-world performance.

The following tips are intended as guidelines that can help enhance the general survey procedures:

Focus on one band (2.4 or 5 GHz) at a time; attempting to do both may take less time, but can cause gaps in the data.

Plan the survey path ahead of time in order to conduct the most complete survey in minimal time.

Be sure to survey from all areas of the network; do not assume that coverage on one side of the access points will be identical to coverage on the opposite side.

Moving too quickly can result in insufficient data collected; however, moving too slowly results in longer processing times due to an excess of information.

Active surveys give a more comprehensive perspective of real-world performance than passive surveys, and are therefore required for a complete survey process.

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RRM Tuning This topic describes how to tune Radio Resource Management (RRM) parameters for a deployed WLAN. After setting up the WLAN network, you should always retest the site using the selected channels and check for any interference. Keep in mind that the RRM algorithms are logical and subject to the physical topology of the network.


Radio Resource Management TuningMany 5-GHz client adapters do not support all 23 channels available.Adjust designated channel assignment (DCA) for RRM on all controllers to support only channels supported by wireless clients.Failure to do so can cause client failure when channels not supported by the wireless clients are used by the associated access points.

While the new Cisco Unified Wireless IP Phones 7921G and 7925 voice handsets support all of the North American 5-GHz channels, not all wireless clients support all of these channels. Many do not support the UNII-2 extended channels 100 through 140 (5.470 to 5.725 GHz). Ensure that only channels enabled on the controller or access points are supported by all wireless clients on the network. Failure to do so can cause coverage holes for clients that do not support certain channels.

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Enabling and Disabling Channels for RRMWireless > 802.11a/n > RRM > DCACheck or uncheck channels supported by wireless clients

802.11n operates on the same channel as 802.11a. For better compatibility with 802.11n clients, you should stay on lower channels (UNII-1 band). Check the list of channels used in channel allocation for access points from the designated channel assignment (DCA) menu by navigating to Wireless > 802.11a/n > RRM > DCA on the controller. You can include or delete a channel from the list.

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Network Appliance and Application Tuning This topic describes how to tune various network appliances deployed in the WLAN. Network appliances that are integrated into the WLAN and communicate with Cisco WCS, such as the Cisco 3300 Series Mobility Services Engine (MSE) or location server, can be tuned so that their refresh time and retry count are used to help limit the number of notifications that are repeatedly generated for uncleared events.


Network Application Notification TuningThe Cisco 3300 Series Mobility Services Engine or location server refresh time and retry count notifications can be modified.Modify notification parameters only if you expect the Cisco 3300 Series MSE or location server to send a large number of notifications or if notifications are not being received.For the MSE, the format for northbound notifications for tags to be sent to a third party is available for developers at:– http://www.cisco.com/en/US/products/svcs/ps3034/ps5408/ps5

418/serv_home.html

To configure notification parameters, follow these steps:

Step 1 In Cisco WCS, navigate to Mobility > Mobility Service Engines.

Step 2 Click the name of the mobility services engine that you want to edit.

Step 3 From the Location menu on the left, select Notification Parameters from the Advanced subheading to display the configuration options.

Step 4 Check the Enable Northbound Notifications check box to enable the function.

Step 5 Check the Tags check box to send tag notifications to third-party applications.

Step 6 Check the check box for each of the tag notification event types (chokepoints, Telemetry, Emergency, Battery Level, and Vendor Data) that you want sent.

Step 7 Check the Include Location check box to send the tag location.

Note You can define which type of location information is sent for the tag. Options include building; X, Y map coordinates; civic (address); city, state, or GEO (longitude, latitude).

Step 8 Enter the IP address and port for the system that is to receive the northbound notifications.

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Step 9 Select the transport type from the drop-down menu.

Step 10 To modify the notification parameter settings, enter the new value in the appropriate field in the Advanced section of the window. Definitions for each of the parameters are listed in the table.

Notification Parameters

Parameter Description

Rate Limit Enter the rate, in milliseconds, at which the MSE will generate notifications. A value of 0 (default) means that the MSE will generate event notifications as fast as possible.

Queue Limit The event queue limit for sending notifications. The MSE will drop any event above this limit. Default value is 500.

Retry Limit Enter the number of times to generate an event notification before the refresh time expires. This value ensures, to some extent, that the events that the MSE generated will eventually reach Cisco WCS. Default value is 1.

The MSE does not store events in its database.

Refresh Time Enter the wait time in minutes that must pass before an event notification is resent. For example, suppose you enter 30 in this field. If a monitored element goes out of a specified area, the MSE sends an event notification. Then, until the event is cleared, the MSE resends an event notification every 30 minutes.

Notifications Dropped (Read only). The number of event notifications dropped from the queue since startup.

Step 11 Click Save to store your updates in the Cisco WCS and MSE databases.

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Verify the Applications This topic describes how to verify the applications using the local client. After conducting an RF site survey and configuring the access point, verification tests should be run to ensure that everything works as desired.


Verify ApplicationsTest all wireless applications, Layer 1 through Layer 7– If handheld devices are to be used, turn them on and test.– Mobile applications such as a respiratory care handheld

application should be tested in all areas where it is to be used.– Perform load testing for client density.– Go live with all wireless applications and test to ensure that

everything is working.

The network is not ready to go live until all applications have been tested on the wireless network Layers 1 through 7. You should perform density testing and load testing. Iperf with AirMagnet Survey PRO can be used to measure throughput to the client and from the client.

You should verify that mobile clients can roam without losing their session with the network and that handoffs are smooth between access points.

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VoWLAN Verification TestingPerform these tasks to verify wireless voice network operation. Check that the wireless IP phones can do the following:– Associate with all access points in the WLAN– Authenticate with all access points in the WLAN– Register with Cisco Unified Communications Manager– Make stationary phone calls with good quality audio– Make roaming phone calls with good quality audio and no

disconnections– Place multiple calls, especially in areas designated for high-

density use

Before the initial deployment of wireless phones in the WLAN, you should perform a site survey to verify that the access points provide adequate coverage and that wireless phones can roam from one access point to another with no audio problems. After the initial deployment, it is a good practice to perform site surveys at regular intervals to ensure continued coverage and roaming.

From the Cisco Unified Wireless IP Phone 7925G, you can use the Neighbor List utility or Site Survey utility from the Settings > Status menu.

Perform these tasks to verify wireless voice network operation. Verify that the wireless IP phones can do the following:

Associate with all access points in the WLAN

Authenticate with all access points in the WLAN

Register with Cisco Unified Communications Manager

Make stationary phone calls with good quality audio

Make roaming phone calls with good quality audio and no disconnections

Place multiple calls, especially in areas designated for high-density use

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SummarySeparate surveys should be done by media type supported (802.11a, 802.11b, 802.11g, or 802.11n).Only channels supported by wireless clients should be enabled on the wireless network. Notification parameters between Cisco WCS and the Cisco 3300 Series MSE or location appliance can be modified, if needed. When the wireless installation is complete, all wireless devices and applications must be tested to ensure they are working properly.

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Lesson 2

Verifying WLAN Readiness

Overview Cisco Wireless Control System (WCS) has several tools for preparing a network with location and Voice over wireless LAN (VoWLAN) services. You can calibrate floors for custom RF modeling. You can run location and VoWLAN readiness tests to ensure that a floor area is ready to support the services.

Objectives Upon completing this lesson, you will be able to describe the steps necessary to use the Cisco WCS tools to verify the readiness of the WLAN to support the desired applications. This ability includes being able to meet these objectives:

Describe how to perform a site calibration using Cisco WCS

Describe how to perform the Cisco WCS location readiness test

Describe how to perform the voice readiness test using Cisco WCS

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Cisco WCS Site Calibration This topic describes how to perform a site calibration using Cisco WCS.


CalibrationIf provided RF models do not sufficiently characterize the floor layout, you can create a calibration model that is applied to the floor and better represents the characteristics of that floor.In environments in which many floors share common characteristics (such as in a library), one calibration model can be created and then applied to floors with the same physical layout and same deployment.

If RF models that are provided do not sufficiently characterize a floor layout, you can create a calibration model that is applied to the floor and better represents the characteristics of that floor. In environments in which many floors share common characteristics (such as a library), you can create one calibration model and apply it to floors with the same physical layout and deployment.

The calibration models are used as RF overlays with measured RF signal characteristics that can be applied to different floor areas. This enables the Cisco WLAN solution installation team to lay out one floor in a multi-floor area, use the RF calibration tool to measure, save the RF characteristics of that floor as a new calibration model, and apply that calibration model to all the other floors that have the same physical layout.

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Data CollectionThere are two methods of data collection:– Data point collection

Calibration points are chosen and their coverage area is calculated one location at a time.This method is best suited for small, enclosed spaces such as office cubicles, private offices, or conference rooms.

– Linear point collectionA series of linear paths are chosen and then calculated as you traverse the path. This approach is generally faster than the data point collection. You can also employ data point collection to augment data collection for locations missed by the linear paths.This method is best suited for covering large open spaces such as corridors, auditoriums, warehouses, or outdoor areas.

You can collect data for a calibration using one of two methods:

Data point collection: Calibration points are chosen and their coverage area is calculated one location at a time.

Linear point collection: A series of linear paths are chosen and then calculated as you traverse the path. This approach is generally faster than the data point collection. You can also employ data point collection to augment data collection for locations missed by the linear paths.

Note A client device that supports both IEEE 802.11a/n and 802.11b/g/n radios is recommended to expedite the calibration process for both spectrums. The client needs to be Cisco Compatible Extension version 2 or later. It is recommend that the access point be set to a channel and a power level that best represents the overall site design criteria. It is also recommended that the client device used for the calibration be the model of the principle application for the site. If you are calibrating for 2.4 GHz and the site will not be using 802.11 and 802.11b data rates, make sure that the access points have those rates disabled.

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Starting the Calibration

Enter the MAC address of the clientSelect the building and floor area

Open a browser to the Cisco WCS server and follow these steps to perform the calibration process:

Step 1 Navigate to Monitor > Maps and select RF Calibration Models from the drop-down menu in the upper right. Click Go.

Step 2 Choose Create New Model from the drop-down menu in the upper right. Click Go.

Step 3 Assign a name to the model and then click OK.

Step 4 The new model appears along with the other RF calibration models, but its status is listed as Not Yet Calibrated. To start the calibration process, select the hyperlink associated with the new model name. A new window appears which indicates the details of the new model. In the upper-right corner, choose Add Data Points from the drop-down menu and click Go.

Step 5 If this process is being performed from a mobile device connected to the Cisco centralized architecture through Cisco WCS, the MAC address field is automatically populated with the address of the device. Otherwise, you can manually enter the MAC address of the device being used to perform the calibration. MAC addresses that are manually entered must be delimited with colons (such as FF:FF:FF:FF:FF:FF).

Step 6 Choose the appropriate campus, building, and floor where the calibration is performed. Click Next.

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Data Point Collection—Positioning the Crosshairs

Adding data points50 distinct locations150 measurements must be taken to complete the calibration

If you want to do a point collection of data for the calibration, follow these steps:

Step 1 Choose Point from the Collection Method drop-down menu and check the Show Data Points check box if not already checked. A calibration point pop-up displays on the map.

Step 2 Position the tip of the calibration point pop-up at a data point (+) and click GO. A panel appears showing the progress of the data collection.

Note Rotate the calibrating client laptop during data collection so that the client is heard evenly by all access points in the vicinity.

Step 3 When the data collection is complete for a selected data point and the coverage area is plotted on the map, move the calibration point pop-up to another data point and click GO.

Note The coverage area plotted on the map is color-coded and corresponds with the specific WLAN standard used to collect that data. Information on color-coding is provided in the legend on the left side of the window. Additionally, the progress of the calibration process is indicated by two status bars above the legend, one for 802.11a/n and one for 802.11b/g/n.

Note To delete data points for locations selected in error, click Delete and move the black square that appears over the appropriate data points. Resize the square as necessary by pressing Ctrl and moving the mouse.

Step 4 Repeat Steps 1, 2, and 3 until the calibrations status bar of the relevant spectrums (802.11a/n or 802.11b/g/n) display as Done.

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Note The calibration status bar indicates data collection for the calibration as Done after date from approximately 50 distinct locations and 150 measurements have been gathered. For every location point saved in the calibration process, more than one data point is gathered. The progress of the calibration process is indicated by two status bars above the legend, one for 802.11b/g/n and one for 802/11a/n.

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Linear Point Collection

Do not stop data collection until you reach the end point, even if the data collection bar indicates completion.

If you want to do a linear collection of data for the calibration, follow these steps:

Step 1 Choose Linear from the Collection Method drop-down menu and check the Show Data Points check box, if not already checked. A line appears on the map with both Start and Finish pop-ups.

Step 2 Position the tip of the Start pop-up at the starting data point.

Step 3 Position the Finish pop-up at the ending data point.

Step 4 Position yourself with your laptop at the starting data point and click GO. Walk steadily towards the end point along the defined path. A panel displays to show that data collection is in process.

Note Do not stop data collection until you reach the end point even if the data collection bar indicates completion.

Step 5 Press the space bar or Done on the data collection panel when you reach the end point. The collection panel displays the number of samples taken before it closes to reveal the map. The map displays all the coverage areas where data was collected.

Step 6 Repeat Steps 2, 3, 4, and 5 until the status bar for the respective spectrum is filled in (done).

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150 Data Points Later

Perform this process for each spectrum in which location services or Cisco Mobility Services Engine (MSE) is required, until the calibration wizard shows that the process is complete. The calibration wizard shows a complete calibration after approximately 50 distinct locations and 150 measurements have been gathered. For every location point saved in the calibration process, more than one data point is gathered. Information on calibration status is provided in a legend on the left side of the window. As data points are collected and areas of the map are properly calibrated, coverage is indicated by colored areas that correspond with the specific WLAN standard used to collect that data. The progress of the calibration process is indicated by two status bars above the legend, one for 802.111/n and one for 802.11b/g/n progress.

Step 7 When the calibration is complete for each spectrum in which location services or Cisco MSE is required, select the name of the calibration model at the top of the window to return to the main screen for that model.

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Calibrate

When calibration is complete, click the Inspect Location Quality link.

Step 8 After all the raw data collection is performed, compile the model, and then Cisco WCS and the location appliance use the data to understand RF attenuation characteristics. To compute the collected data points, choose Calibrate from the drop-down menu and click Go.

Step 9 Click the Inspection Location Quality link found under the Calibration Floors heading. A color-coded map noting percentage of location errors appears.

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Inspect Location Quality

This figure is an example of a floor deployment in which the areas surrounding the access points came out the best. Although the darkest green areas are towards the center of the figure, notice that yellow and orange areas to the right are not as good.

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Edit Floor Area to Apply Calibration Model

Step 10 To use the newly created calibration model, you must apply the model to the floor on which it was created (and on any other floors with similar characteristics as well). Navigate to Monitor > Maps and find the specific floor to which the model is applied. At the floor map interface, choose Edit Floor Area from the drop-down menu and click Go.

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Select Your RF Model

Step 11 From the Floor Type (RF Model) drop-down menu, choose the newly created calibration model. Click OK to apply the model to the floor.

Note This process can be repeated for as many models and floors as needed. After a model is applied to a floor, all location determination performed on that floor is done using the specific collected attenuation data from the calibration model.


New Model Applied to Floor

When the new model is applied to the floor, you can locate a client on the heat map.

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Monitor > Clients > New Search > Go

To use Cisco WCS to find clients on your WLAN, follow these steps:

Step 1 Navigate to Monitor > Clients and then to the Clients Summary page.

Step 2 The sidebar area enables you to select a new configuration panel under the menu area that you have selected. You can make only one choice. The selector area options vary based on the menu that you select, and include these options:

New Search: Opens the Search Clients window. Use the Search Clients window to configure, run, and save searches.

Saved Searches: Lists the saved custom searches. To open a saved search, choose it from the Saved Searches list.

Edit link: Opens the Edit Saved Searches window. You can delete saved searches in the Edit Saved Searches window.

Step 3 In the sidebar, click New Search. The Search Clients window appears.

Step 4 Choose All Clients in the Search By drop-down menu and click GO. The related search results window appears. The search results are listed.

Step 5 Click the username of the client that you want to locate. Cisco WCS displays the corresponding Client Name page.

Note The Client Received Signal Strength Indicator (RSSI) History, Client signal-to-noise ratio (SNR) History, Bytes Sent and Received, and Packets Sent and Received reports are displayed. You can specify graph view or table view by clicking the appropriate icon. If it is a report where you can specify time period, enter both the start and end time or a specific time period.

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Select Present Map (High Resolution) > Go

Step 6 To find the client, choose one of these options from the Select a command drop-down menu and click GO:

Recent Map (High Resolution): Finds the client without disassociating it.

Present Map (High Resolution): Disassociates the client and then finds it after reassociation. When you choose this method, Cisco WCS displays a warning message and asks you to confirm that you want to continue.

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Actual Location

Actual Location

The illustration in the figure shows the location of access points in the corners of the floor plan. The recommendation for increased location accuracy is to have access points located in corners and along outside walls.

If you are using Cisco WCS Location, Cisco WCS compares the RSSI signal strength from two or more access points to find the most probable location of the client and places a small laptop icon at its most likely location. If you are using Cisco WCS Base, WCS relies on the RSSI signal strength from the client and places a small laptop icon next to the access point that receives the strongest RSSI signal from the client. The figure shows a heat map that includes a client location.

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Cisco WCS Location Readiness Test This topic describes how to perform the WCS location readiness test.


Monitor > Maps Building2 > First Floor

The Inspect Location Readiness feature is a distance-based predictive tool that can point out problem areas with access point placement.

The Inspect Location Readiness tool does the following:

Displays areas that have the required access point coverage and will provide accurate location results.

Takes into consideration the placement of each access point along with inter-access point spacing.

Assumes that access points and controllers are known to Cisco WCS.

A point is defined as “location-ready” if the following is true:

At least four access points are deployed on the floor.

At least three access points are within 70 feet (21 meters) of the point-in-question.

At least one access point is found to be resident in each quadrant surrounding the point-in-question.

To access the Inspect Location Readiness tool, follow these steps:

Step 1 Navigate to Monitor > Maps.

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Inspect Location Readiness

Step 2 Choose the applicable floor area name.

Step 3 From the Select a Command drop-down menu, click Inspect Location Readiness.

The following color schemes indicate whether or not the area is location-ready:

Green: Yes

Red: No

Areas within the access points are location-ready. Areas outside the rectangle of access points are not location-ready.

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Cisco WCS Voice Readiness Test This topic describes how to perform the voice readiness test using Cisco WCS. The Cisco WCS Voice Readiness Tool (VRT) provides a visual indication of the RF coverage and provides an assessment of the readiness of the deployment for VoWLAN.


Monitor > Maps Building2 > First Floor

The VoWLAN Voice Readiness Tool allows you to verify that the RF coverage is sufficient for your voice needs. This tool verifies RSSI levels after access points have been installed.

To access the VoWLAN Readiness Tool, follow these steps:

Step 1 Navigate to Monitor > Maps.

Step 2 Choose the applicable floor area name.

Step 3 From the Select a Command drop-down menu, click Inspect VoWLAN Readiness.

Step 4 Choose the applicable Band, AP Transmit Power, and Client parameters from the drop-down menus.

Note By default, the region map displays the region map for the 802.11b/g/n band for a Cisco phone-based RSSI threshold. The new settings cannot be saved.

Step 5 Depending on the selected client, the RSSI values may not be editable.

Cisco Phone: RSSI values are not editable.

Custom: RSSI values are editable with the following ranges:

— Low threshold: –95 dBm to –45 dBm

— High threshold: –90 dBm to –40 dBm

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VoWLAN Readiness

Step 6 The following color schemes indicate whether or not the area is voice-ready:

Green: Yes

Yellow: Marginal

Red: No

Troubleshooting Voice RF Coverage Issues Perform the following to troubleshoot voice RF coverage issues:

To prevent one-way audio problems because of the lack of proper radio coverage, set the access point power levels to match the power levels of the VoWLAN client. To have radio coverage from the VoWLAN client to the access point match coverage from the access point to the VoWLAN client, the access point Tx power level cannot exceed the maximum Tx power of the client.

To determine if the coverage area is going to have enough access points to support the VoWLAN client, all of the access points must have a Tx power level that does not exceed that of the client. The power levels supported by the client and access point may change by the 5-GHz channel. Therefore, the readiness process should be based on a channel that will be used by the site that has the lowest maximum Tx power.

Verify the green, yellow, and red regions of the RF environment. These indicators are accurate whether the floor is calibrated or not, but floor calibration improves the accuracy because it adds floor-level attenuation.

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SummaryIf an RF model does not sufficiently characterize the floor, a calibration procedure can be performed to create an RF model for the floor.To create an RF model, a minimum of 50 distinct locations and 150 measurements must be taken. A location readiness test can be performed to see if a floor is location-ready.A VoWLAN readiness test can be performed to see if a floor is ready to support voice services.

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Lesson 3

Presenting an Installation Report

Overview An installation report covers device installation configuration and addressing of the network devices installed. The installation report also includes verification testing of the WLAN devices and services running.

Objectives Upon completing this lesson, you will be able to describe the information needed in an installation report. This ability includes being able to meet these objectives:

Describe the contents of an installation report

Describe the information given to the customer in an installation report

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Preparing an Installation Report This topic describes the contents of an installation report. After completing an installation, do not forget to carefully document what was done.


Installation Report ContentsWhen a wireless installation is complete, including testing and turnup, an installation report should be generated containing the following information:

– Map of cable drop locations with labeling scheme– Cable scan results (pass or fail) which include:

Test of all pair combinations to 250 MHz for Category 5EMeasurement of near-end crosstalk– 500 MHz for Category 6A

Test of attenuationTest of return lossTest of length of cableTest of capacitance

– Printed cable scan certification results should be attached or inserted into installation report

After access point placement has been determined, cable must be pulled to support the access points. This requires the installation and termination of Category 5E or 6 cable with RJ-45 jacks or plugs attached to the cable, with T568B termination.

After you have finished installing the cable, it should be tested to ensure that it is terminated properly and passes Electronic Industries Association (EIA), Telecommunications Industry Association (TIA), Telecommunications System Bulletin (TSB) 67 and 95 standards. This is commonly done with a Microtest PentaScanner. An injector is attached to one end of the cable run and the scanner is attached to the other end of the cable run.

The test either passes or fails in the following areas:

Test of all pair combinations to 100 MHz for Category 5E

Test of all pair combinations to 250 MHz for Category 6

Measurement of near-end crosstalk

Measurement of attenuation

Test of return loss, resistance, and impedance

Test of length of cable (If the cable exceeds 100 meters, the test fails)

Test of capacitance and crosstalk

Performance of a wire map test to ensure that no pairs are crossed and that all pairs are terminated correctly

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When the cable is certified, the results should be either inserted or attached to the installation report.


Installation Report Contents (Cont.)Installation inventory report which contains:– Controllers with the following information:

Controller nameIP addressLocationSerial numberModelSoftware versionMobility groupReachability status

Detailed information of all devices installed should be included in the installation report. For controllers, the following information should be included in the report:

Controller name

IP address

Location

Serial number

Model

Software version

Mobility group

Reachability status

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Installation Report Contents (Cont.)Access points with the following information:– IP address– Model– Software version– Map location– Controller name– Primary controller– Admin status – AP mode– 802.11a/n status– 802.11b/g/n status– Serial number

When access points are deployed, the following information should be included in the report:

IP address

Model

Software version

Map location

Controller name

Primary controller

Admin status

AP mode

802.11a/n status

802.11b/g/n status

Serial number

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Installation Report Contents (Cont.)Location or MSE servers with the following information:– Model number– Serial number– IP addressing– Software version– Admin status

When location or Cisco Mobility Services Engine (MSE) servers are deployed, the following information should be included in the report:

Model number

Serial number

IP address

Software version

Admin status

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Cisco WCS Combined Inventory ReportReports > Inventory Reports > Combined Inventory ReportThe Combined Inventory Report displays the combined output of the following reports:– Controllers – Location servers– Access points

Running this report is simple and generates data for the installation report.

The Combined Inventory Report provides data on all deployed controllers, access points, and location appliances. The data that is returned includes but is not limited to base radio MAC and 802.11a/n or b/g/n radio MAC.

To access the Combined Inventory Report, follow these steps:

Step 1 Navigate to Reports > Inventory Reports.

Step 2 From the left menu, click Combined Inventory Report.

In the report window, saved reports are displayed in a table.

To create a new Combined Inventory Report, follow these steps:

Step 1 Navigate to Reports > Inventory Reports > Combined Inventory Report page > Select a Command > New.

Step 2 Click GO.

Step 3 Specify a report title.

Step 4 Click the Schedule tab to complete the scheduling process.

Step 5 Click Save, Save and Run, Run Now, or Cancel.

You can manage saved reports using the Select a Command drop-down list.

To edit or run a saved report, click a report name under Report Title.

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Installation Report Contents (Cont.)A network diagram should be included, indicating a visual of device connectivity.A spreadsheet should be included indicating wiring closet and switch port connectivity for all devices (controllers, access points, and so on).All wall plates and distribution points should be clearly labeled and documented in the installation report.

How devices interconnect to the network is important to assist in troubleshooting. A network diagram should clearly indicate a visual for device interconnectivity. A spreadsheet should be included with the report indicating all device switch port connectivity as well as wall plate and distribution point labeling for all interconnected devices on the network.

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Installation Report Contents (Cont.)Results of coverage audit performed with AirMagnet Survey PRO– Results should be per media

installed (802.11a/b/g/n)

A final coverage check of the facility was performed with AirMagnet Survey PRO to ensure that all signal levels are what they should be. The results should be added to the installation report. This will indicate the health of the wireless network at the time of completion of the project.


Installation Report Contents (Cont.)Results of location readiness test This should represent that the floors are location-ready

If location services are part of the services offered, a location readiness test is run and floors are calibrated, if required, to improve location accuracy. The results of the floor location readiness test should be included in the installation report.

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Installation Report Contents (Cont.)Results of VoWLAN readiness test– This should represent that the floors are voice-ready

If Voice over wireless LAN (VoWLAN) services are part of the services to be offered, extensive testing is done to ensure that voice services are working properly. Test results should be included in the installation report.


Installation Report Contents (Cont.)All network configurations for mobility and RF groups should be documented and included in the installation report.VLANs created for WLANs should be documented and included in the installation report.Soft copies of configurations for switches, routers, controllers, and location appliances should be saved and included on a CD or DVD and provided with the installation report.

Configurations for all WLAN network devices should be backed up and saved to disk. A CD-ROM or DVD with configuration files should be included with the installation report.

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Presenting an Installation Report This topic describes the information given to the customer in an installation report. After adjustments to the design, based on the RF audit, it is now time to deploy the access point. Documentation of the network “As Built and Configured” is critical to capture at this stage, because RF environments tend to change over time.


Installation ReportUpon completion of the installation and coverage verification, an installation report should be completed.The report documents the installation and configuration of the WLAN.

An installation report documents the installation and configuration of the WLAN. This becomes a living document on how WLAN devices are configured. The document contains information about the installation and WLAN configuration, including IP addressing.

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SummaryThe site installation report should include cable test results. All verification testing and results should be included in the installation report.

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Module SummaryAfter the WLAN is installed, verification of RF coverage is performed. RRM tuning is performed to ensure that no channels are used on the WLAN that are not supported by wireless clients.When VoWLAN services are installed, verification testing with voice handsets is performed to ensure that they operate properly. A voice readiness test should be run on Cisco WCS.When location-based services are installed, a location readiness test should be run on Cisco WCS.You should test accuracy of tags and clients with Cisco WCS; a calibration of the floor may be needed to improve accuracy.Upon completion of testing and tuning of a new WLAN installation, an installation report should be completed, to be delivered to the customer.

When the installation of a WLAN is complete, a thorough RF coverage check should be performed to ensure that proper coverage and signal levels have been obtained. All services to be supported should be tested on Layers 1 through 7. If Voice over Wireless LAN (VoWLAN) services are to be supported, extensive call testing should be performed to ensure that all voice operations are working properly. If location services are to be supported, accuracy testing of the location of tags and clients should be checked to ensure that the location services operations are performing as expected. A floor calibration may be required for better accuracy of location tags and clients.

After the WLAN has been tested and tuned, and wireless applications are operating as expected, an installation report should be completed and delivered to the customer. The installation report should be very detailed and reflect all testing that was performed to insure proper operation of all wireless services delivered.

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Q1) What utility can be used with AirMagnet Survey PRO to check 802.11n uplink and downlink speeds? (Source: Verifying the RF Coverage) A) Iperf B) ADU C) ACU D) Spectrum Expert

Q2) When performing a site survey, each media (802.11a/b/g/n) should be surveyed independently. (Source: Verifying the RF Coverage) A) true B) false

Q3) If a particular floor model does not seem to work well, what can be done to create another model for the floor? (Source: Verifying WLAN Readiness)

Q4) When performing a calibration, what are the two ways to collect data? (Source: Verifying WLAN Readiness)

Q5) A minimum of how many data points must be collected to perform a floor calibration? (Source: Verifying WLAN Readiness) A) 100 B) 125 C) 150 D) 175

Q6) The Cisco WCS VoWLAN location readiness test requires a minimum of how many access points? (Source: Verifying WLAN Readiness) A) three B) four C) five D) six

Q7) A point is defined as location-ready if at least three access points are within 70 feet of the point-in-question. (Source: Verifying WLAN Readiness) A) true B) false

Q8) What tool does Cisco WCS use to verify that the WLAN floor is ready to support VoWLAN? (Source: Verifying WLAN Readiness)

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Q9) Data cable should be certified and the results should be included in the installation report. (Source: Presenting an Installation Report) A) true B) false

Q10) Cisco WCS can perform an inventory report for which network devices? (Source: Presenting an Installation Report)

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Module Self-Check Answer Key Q1) A

Q2) A

Q3) calibration

Q4) data point collection or linear point collection

Q5) C

Q6) B

Q7) A

Q8) voice readiness test

Q9) A

Q10) controllers, access points, and location servers

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