Cisco Wireless

This document is customized and covers basic wireless information and Knowledge for group of users who

are very new to wireless technology.

Need of Wireless Wireless Fundamentals Regulatory Bodies Wireless Topologies Adhoc VS Infrastructure network Service Set Wireless Network Types Cisco Unified Wireless Network Components Cisco Unified Controller- Based Solution Access points Models Wireless LAN Controller Models Access Points Types FAQs

Agenda

Need of Wireless

Need of Wireless Convenience: All notebook computers and many mobile phones today come

equipped with the WiFi technology required to connect directly to a wireless LAN.

Mobility: Employees can stay connected to the network even when they're not at their desks. People in meetings can access documents and applications. Salespeople can check the network for important details from any location.

Ease of setup: When you don't have to run physical cables through a location, installation can be quick and cost-effective. Wireless LANs also make it easier to bring network connectivity to hard-to-reach locations, such as a warehouse or factory floor.

Scalability: As your business operations grow, you may need to quickly expand your network. Wireless networks can typically expand with existing equipment, while a wired network might require additional wiring.

Security: Controlling and managing access to your wireless network is important to its success. Advances in WiFi technology provide robust security protections so your data is easily available to only the people you allow access.

Cost: It can cost less to operate a wireless LAN, which eliminates or reduces wiring costs during office moves, reconfigurations, or expansions.

RF Principles

Wavelength: The physical distance from one point of the cycle to the same point in the next cycle is called a wavelength , which is usually represented by the Greek symbol λ (lambda).

Frequency : Number of times radio waves repeat their pattern per second. It is measured in Hertz.

Reflection: When the radio wave hits the obstacle at a low angle, the wave (the entire wave, or part of it) might bounce on the obstacle. This phenomenon is called reflection.

Multipath: A signal sent to a station travels in a straight line and reaches the destination. A few microseconds later, copies of the same signal reflected on walls, ceiling, and obstacles also reach the destination.

Refraction: Refraction occurs when a wave changes direction. This change in direction usually happens when a wave passes from one medium to another (from air to water, for example).

Scattering: Reflection also occurs in the air itself, bouncing on dust or micro drops of water (humidity). These multiple reflections are described as scattering .

RF Principles

Free Path Loss: Even without obstacles, a radio wave gets weaker as it moves away from the emitting source because the energy of the wave spreads .

RSSI: Because the RF wave might have been affected by obstacles in its path, it is important to determine how much signal is received by the other endpoint. The value that indicates the amount of power received is called Received Signal Strength Indicator (RSSI).

RF Principles Continue…

Regulatory Bodies

IEEE : It defines how the signal is sent carrying data over unlicensed frequency band. IEEE maintains and creates technical standards and protocols used by wireless LAN devices.

Federal Communications Commission (FCC): In America and other countries in America continents, FCC restrict the power and frequency can be used in that region.

ETSI (European Telecommunications Standards Institute): Controls Frequency and power in Europe and other countries like Israel and some other countries.

Wi-Fi Alliance: It ensures that wireless products that are available to consumers provide the features that the products claim to have.

Regulatory Bodies

Wireless Topologies

Wireless personal-area networks (WPAN): Have a short range (up to 5–10 meters), commonly use the 802.15 family of specifications to connect two or a few devices with low power consumption. Bluetooth is an example of WPAN protocol.

Wireless local-area networks (WLAN): Consume more power but extend the connection to about 300 feet (100 meters).

Wireless metropolitan-area network (WMAN): Extend the range to a larger geographic area, such as a city or suburb. WMANs typically use licensed frequencies . Although implementations in the ISM bands can also be found. WiMAX is an example of WMAN protocol.

Wireless wide-area network (WWAN): Provide connectivity over a wide geographical area. Usually, WWANs are networks used for mobile phone and data service and are operated by carriers. WWANs typically use licensed frequencies.

Wireless Topologies

Adhoc Vs Infrastructure Network

Adhoc Mode: ◦ Also known as Peer-to-Peer network. ◦ A first station defines the radio parameters and a connection name; the other

stations just need to detect the connection and adjust their own parameters to connect to the first station and to each other.

◦ As soon as wireless devices connect to each other over a wireless network, a Basic Service Set (BSS) is formed.

◦ The wireless network they form is called an Independent Basic Service Set (IBSS).

Adhoc VS Infrastructure Network

Infrastructure Mode: The AP functions as a translational bridge between 802.3 wired media and 802.11 wireless media. ◦ BSS is the service provided by the AP.

Adhoc VS Infrastructure Network continue…

Service Set

Basic Service Area (BSA) : Wireless Cell created by an AP – CISCO term.

Independent basic service set ( IBSSD): Wireless network created by a Laptop.

Used in ADHOC Connection.

Basic service set – (BSS): As soon as wireless devices (called “stations” in the 802.11 standard) connect to each

other over a wireless network a BSS is formed.

Distribution System (DS): The wired section of the network that can be reached through the AP.

Extended service set – (ESS): When the distribution system links two APs, or two cells, the group is called extended

service set.

Allows mobility roaming of wireless devices within a distributed system.

Service Set Identifier – (SSID): Wireless Workgroup or Domain Name or simply a wireless network.

ASCI string providing a name to a wireless network.

SERVICE SET

Basic Service Set Identifier –(BSSID): AP Radio MAC address associated with a SSID.

Multiple Basic Service Set Identifier –(MBSSID): Having multiple SSIDs configured.

SERVICE SET Continue…

Wireless Network Types

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Wireless Network Types

The first version of the 802.11 standard, released in 1997,

It described FHSS 1 Mbps, and DSSS 1 Mbps and 2 Mbps in the 2.4 GHz spectrum, describing 14 channels.

802.11 is a rich family of protocols.

The standard was revised in 2007 to integrate all the amendments published over the previous years (integrating 802.11a, b, d, e, g, h, i, and j). This cumulative version of the standard is called 802.11-2007

802.11 continue…

802.11 was modified almost as soon as it was created to allow for faster speeds.

802.11b was published in 1999

It described CCK to bring the data rate to 5.5 Mbps and 11 Mbps.

802.11b continue…

802.11b was also too slow. A new amendment was published in 2003 introducing OFDM to the 2.4 GHz band, and effectively. It allowing rates up to 54 Mbps.

802.11g is built to be backward compatible with 802.11b

When an 802.11b station is detected in the cell, the AP informs the cell in its information broadcasts. These broadcasts contain 2 bits set to 1: “non-ERP (that is, non-802.11g) present” and “use protection.

The downside of this protection mechanism is wasted time before each 802.11g frame. This protection mechanism typically divides the overall throughput of the cell by 3.

802.11g continue…

The 802.11a amendment was published in 1999.

802.11a uses OFDM only (6 Mbps to 54 Mbps).

802.11a offers up to 23 nonoverlapping channels.

Channels are 20 MHz apart.

802.11a continue…

802.11n continue…

Primary 802.11n Components

40-MHz Channels Improved MAC Efficiency

Multiple-Input, Multiple-Output (MIMO)

Two adjacent 20-MHz channels are combined to create a single 40-MHz channel.

MAC aggregation packs smaller packets into a single unit.

Block acknowledgment improves throughput.

Maximal Ratio Combining (MRC)

Beam forming

Spatial multiplexing

802.11g and 802.11a use 20-Mhz channels.

802.11n aggregatestwo carriers to increase the throughput

802.11n Channel Aggregation Continue…

802.11 requires acknowledgment of each frame.

Block Acknowledgment Continue…

802.11n uses block acknowledgment for constituent frames.

802.11Header

Packet

802.11ACK

802.11nACK

802.11nHeader

Packet 802.11nHeader

Packet 802.11nHeader

Packet

MRC is used by the receiver with multiple antennas to optimally combine energies from multiple receive chains. An algorithm eliminates out-of-phase signal degradation.

Maximal Ratio Combining Continue…

The emitter can send the same signal from several antennas. By carefully coordinating these signals based on the feedback transmitted by the 802.11n receiving station, the emitter aims at making these signals be received in phase, thus increasing the signal power level at the receiving station, allowing for longer range or higher throughput.

Transmit Beamforming Continue…

The emitter can send different simultaneous signals from different radios. The 802.11n receiver will receive these signals on all its radios. Each of the receive radios independently decode the arriving signals. Then, each receive signal is combined with the signals from the other radios. This results in additional throughput.

Spatial Multiplexing Continue…

MIMO Benefits Continue…

Cisco Unified Wireless Network Components

Network Services

Network Management

Network Unification

Access Points

Client Devices

Cisco Unified Controller-Based Solution

Access points Models

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Controllers Models

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Access Points Types

Standalone and Lightweight Aps

Repeaters Continue…

Extends the AP coverage

Dual radio can create dual half-duplex

Overlap of 50% required

Throughput impacted when single frequency used

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A WGB provides wireless connection from Ethernet port.

Several devices can benefit if the WGB is connected to a hub or a switch.

Workgroup Bridge Continue…

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Extend the LAN by linking LANs

Usually a few miles range

Point to point or hub and spoke

Outdoor Wireless Bridges Continue…

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Devices are connected with redundant connection between nodes; no single point of failure

Mesh Networks Continue…

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What is a Wireless Network?A wireless local-area network (WLAN) uses radio waves to connect devices, such as laptops, to the Internet and to your business network and applications

How Far Does the Signal Reach?A wireless router or access point's signal typically extends up to approximately 300 feet.

Who Uses WLANs?WLANs are frequently offered in public places such as cafes, hotels, and airport lounges. In addition, many businesses have wireless networks throughout their office buildings or campuses for employee and guest use.

What Equipment Do I Need?Most laptops have built-in wireless networking. If yours doesn't, you'll need a wireless network adapter card, which is typically inexpensive and easy to install.Many routers act as WLAN access points. They connect multiple computers (and wireless-capable printers) to a single WLAN and to the Internet.You can extend WLANs throughout an area by placing additional wireless access points in various locations. The access points extend the wireless signal's range and strength.

FAQ

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How Can I Secure a WLAN?There are many ways to secure your WLAN, including:◦ Data encryption, which only gives authorized users access to information over

your wireless network◦ User authentication, which identifies computers trying to access the network◦ Secure access for visitors and guests◦ Control systems, which protect the laptops and other devices that use the

network Can two computers communicate using the wireless client cards

without an access point (AP)?◦ Yes, two computers can communicate using the wireless client cards without

an AP. Connect the PC cards in Ad Hoc mode. This step eliminates peer interaction, and one PC becomes the master.

Can you share the internet between two computers?◦ No, you cannot share the internet. You need to install additional software to

share an internet connection.

FAQ continue…

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Questions ????Drop an email to

EMEA&APAC_MSI_ENS@hcl.com