CIT 1100

Wireless Networks

In this chapter you will learn how to: Describe the basics of wireless networking

Explain the differences between wireless networking standards

Configure wireless networks

Wireless Networks

A wireless network eliminates the need for network cabling to connect PCs to one another Instead of a physical set of wires, wireless

networks use radio waves to communicate The wireless radio wave networks you'll be

supporting are those based on the most common implementation of the IEEE 802.11 wireless Ethernet standard (Wi-Fi) and those based on Bluetooth technology

Wireless Networking Basics

Wireless networking capabilities of one form or another are built into many modern computing devices Wireless Ethernet and Bluetooth capabilities

are available as integrated components, or they can easily be added using PCI or PCie

You can also add wireless network capabilities using an external USB wireless NIC cards

Wireless Networking Components

Wireless NICs aren't limited to PCs Smartphones can have built-in wireless

Wireless Networking Components

To extend the capabilities of a wireless Ethernet network, such as by connecting to a wired network or by sharing a high-speed Internet connection, you need a Wireless Access Point A WAP centrally connects wireless network

nodes the same way that a network hub or switch connects wired PCs 

Wireless Networking Components

Configuring wireless networking software is greatly simplified, network adapters are Plug and Play so any late version of Windows recognizes one when installed into a PCI or PCie slot, or a USB port Networks need a name which you will be

prompted for during configuration

Wireless Networking Software

Click on the Wireless select ICON

Select Wireless network by Name

There are two different methods available with wireless ad hoc mode and infrastructure mode Ad hoc mode, also called peer-to-peer mode,

each node is in direct contact with each other node

Ad hoc mode networks are easier to configure than infrastructure-mode networks ◦ Suited for small groups of computers that need to

transfer files or share printers◦ Also good for temporary networks such as study

groups or business meetings

Wireless Network Modes

There are two different methods available with wireless ad hoc mode and infrastructure mode Infrastructure mode use one or more WAPs to

connect Designed for wireless network with many PCs,

needs to have centralized con trol over the wireless network

To connect wire lessly to another network, such as the Internet, you need to use infrastructure mode

Wireless Network Modes

One of the major complaints about wireless networking is that it offers weak security Often the only requirement to access a

wireless network is walk into an unsecured WAP's coverage area and turn on your wireless device

Unsecured Data packets float through the air instead of traveling safely wrapped up inside network cabling

These packets can be intercepted

Wireless Networking Security

Wireless networks use multiple methods to secure access to the network itself and secure the data being transferred Changing the default Service Set Identifier (SSID)

parameter- also called the network name- and administrator password is the first step

The SSID is a 32-bit identifier for your WAP that is meant to be unique, but many WAPs ship with the same SSID and remain unchanged by unsuspecting users

Enabling wireless encryption - Wired Equivalent Privacy (WEP), Wi-Fi Protected Access (WPA), or WPA2 ensures that the data packets are secure in transit

Wireless Networking Security

The main security weaknesses in wireless networks is that out of the box, no security is configured Wireless devices want to be heard, and by

default WAPs are configured to broadcast their presence to their maximum range, welcoming all other wireless devices that respond

Always change the default SSID to something unique, and change the administrator password right away

SSID and Administrator Password

SSID and Administrator Password

http://www.phenoelit-us.org/dpl/dpl.html

How secure are default passwords?

Wired Equivalent Privacy (WEP) encryption was meant to secure data being wirelessly transmitted. WEP encryp tion uses a standard 40-bit encryption to scramble data packets Unfortunately WEP can be cracked in a

matter of minutes using software readily available off the Internet

WEP is better than noth ing, but only stops casual prying into a network

Encryption

Wireless Protected Access (WPA) encryption addresses the weaknesses of WEP it functions as a security protocol upgrade to WEP-enabled devices WPA offers security enhancements such as an

encryption key integrity-checking feature and user authentication through the industry-standard Extensible Authentication Protocol (EAP)

The use of EAP is a huge security improvement over WEP. User names and passwords are encrypted and therefore much more secure

Encryption

Recent versions of Mac OS-X and Microsoft Windows support WPA2 for securing wireless networks WPA2 uses Advanced Encryption Standard

(AES), among other improvements, to provide a secure wireless environment

WPA2 should be the security used on all Wireless systems

Encryption

Wireless speeds depend on several factors mostly dependent upon the standard used by the wireless device Another factor affecting speed is the distance

between wireless nodes (or between wireless nodes and centralized WAPs). ◦ Devices dynamically negotiate top speed at which they can

communicate without dropping too many data packets ◦ Speed decreases as distance increases, so the maximum

throughput speed is achieved only at extremely close range (less than about 25 feet).

◦ At the outer reaches of a device's effec tive range, speed may decrease to around 1 Mbps before it drops out altogether

Wireless Networking Speed

Speed can also be affected by interference from other wireless devices operating in same frequency range

Cordless phones Baby moni tors Microwave Ovens Solid objects

Deadspots occur when something capable of blocking the radio signal comes between wireless network nodes

Electrical appli ances are very effective at blocking wire less network signals

Other culprits include electrical fuse boxes, metal plumbing, and air conditioning units

Wireless Networking Speed

Range is greatly affected by outside factors, Interference from other wireless devices will affects range, as does interference from solid objects Range can be increased in a couple of ways:

◦ Installing multiple WAPs to permit "roaming" between one WAP's coverage area and another

◦ Install a higher-gain antenna on some models that increases a single WAP's range

◦ Directional antennas can be used to dramatically increase range in specific directions

Wireless Networking Range

Standards for Wireless are based on the 802.11 and Bluetooth Standards The IEEE 802.11wireless Ethernet standard defines

methods by which devices can com municate using spread-spectrum radio waves

Spread-spectrum broadcasts data in small, discrete chunks over the different frequencies (channels) available within a certain frequency range

802.11-based wireless technologies broadcast and receive on one of two license free industrial, scientific, and medical (ISM) radio bands: 2.4 GHz and 5.8 GHz

Wireless Networking Standards

Currently Wi-Fi is the most widely adopted type of wireless networking used by homes, public places, coffee shops, libraries… Only wireless devices that conform to the extended

versions of the 802.11 standard- 802.11a, 802.11b, 802.11g, and 802.11n- are Wi-Fi certified

Certification comes from the Wi-Fi Alliance, a nonprofit industry group made up of more than 175 member companies designing and manufacturing wireless networking products

Most wireless equipment will communicate with different devices, 802.11b will communicate with 802.g, the exception is 802.11a which operates on a different frequency

Wireless Networking Standards

802.11a differs from all others in significant ways: 802.11-based standards operates on a different

frequency range, 5GHz This less-used frequency range means that

802.11a devices are less prone to interference from other devices

802.11a also offers considerably greater throughput than 802.11b, reaching speeds up to 54 Mbps

Range is somewhat less about 150 feet Despite the superior speed of 802.11a, it isn't

widely adopted in the PC world

Standards

802.11b was the first widely accepted standard in wireless networking 802.11b supports data throughput of up to

11Mbs and maxi mum range of 300 feet In a typical office environment, its maximum

range is lower Downside to 802.11b - it uses a very popular

frequency 2.4 GHz band which is already crowded with baby monitors, garage openers, microwaves, and wireless phones, so you're likely to run into interference from other wireless devices

Standards

802.11g uses the best of both 802.11a and b creating a single standard 802.11g offers transfer speeds equivalent to

802.11a, up to 54 Mbps, with the wider 300-foot range of 802.11b

More importantly, 802.11g runs in the 2.4 GHz band, so it is backward-compatible with 802.11b, meaning that the same 802.11g WAP can service both 802.11b and 802.11g wireless nodes

The 802.11g standard is popular, but losing ground to the newest version, 802.11n

Standards

802.11n standard brings improvements to Wi-Fi networking- faster speeds, new antenna technology 802.11n specification requires all but handheld

devices to use multiple antennae - a feature called multiple in/multiple out (MIMO), enabling the devices to make multiple simultaneous connections

With up to four antennae, 802.11n devices can achieve amazing speeds up to 600 Mbps

Like 802.11g, 802.11n WAPs run in the 2.4 GHz band, supporting earlier, slower 802.11b/g devices

The 802.11n standard also has a more powerful so-called dual-band capable of supporting 802.11a devices as well as 802.11b/g devices

Standards

Standard

Max. speed

802.1 1a 54 Mbps

802.11b 11 Mbps

802.1 1g 54 Mbps

801.1 1n

100+ Mbps       

Max. range 150 feet 300 feet 300 feet 300+ feetFrequency 5 GHz 24GHz 2.4 GHz 2.4 and 5 GHzCompatibility 802.11a 802.11b 802.11b,802.11g 802.11b,802.11g.

802.11 n (802.11a in some cases)

Description Eight available channels. Less prone to interference than802.11b and802.11g.

Fourteen channels available in the 2.4 GHz band (only 11 of which can be used in the U.S. due to FCC regulations).

Improved security enhancements Fourteen channels available in the 2.4GHz band (only 11 of which can be used in the U.S. due to FCC regulations)

Same as 802.11 g but adds the 5 GHz band that 802.11a uses.