Version 1.1 2006Slide 1 Format of lecture Introduction to Wireless Wireless standards Applications Hardware devices Performance issues Security issues

Version 1.1 2006 Slide 1

Format of lecture

Introduction to WirelessWireless standardsApplicationsHardware devices Performance issues Security issues


Wireless Technology

Wireless and mobile computing are the keywords Very topical/excitingThis technology not yet maturePromises that we can improvise our existing

networks without having to lay new wires - roving staff will just have to insert a wireless card into their device and join the network

Interesting to compare the what the Telco’s are doing with 3G and how this rivals WiFi hotspots


Wireless Technology

Wireless technology has to compete with digital satelliteCablephone lines (HomePNA) 10MbpsPower line (HomePlug) 14Mbps

Wireless broadband technology (WiMax) gives wire-free transmission of two way multimediaBandwidth is an issue here


Wireless Technology

What is on the market/coming?Communication cards to allow data from personal

digital assistants to be synchronised with desktop PC’s

Cards to link laptops and PC’s with Global System for Mobiles(GSM) based phones and local area network devices

All the above enables firms to set up wireless networks without having to use Ethernet cable


Wireless Protocols

Wireless LANBluetoothWAP/GPRS/UMTSSWAP - Shared Wireless Access Protocol3G - third generation cellular standard


Wireless versus Wired networks

Using Radio frequency (2.4GHz and 5GHz)Easy to setup a small office or home office

(SOHO)MobilityTravel through wallEasy for network reconstruction


What is WiFi?

Wireless LAN IEEE 802.11x networkPromulgated by an association called WiFi

AllianceWiFi Alliance certifies all wireless LAN

IEEE802.11x based products for interoperability

All IEEE802.11x based products that passed the WiFi Alliances are called WiFi

Wireless Fidelity


WiFi Standards

IEEE 802.11aAn IEEE standard for a wireless network that

operates at 5 GHz with rates up to 54Mbps IEEE 802.11b

An IEEE standard for a wireless network that operates at 2.4 GHz with rates up to 11Mbps

IEEE 802.11g – referred to as 54g (but don’t confuse that with the 54Mbps!)An IEEE standard for a wireless network that

operates at 2.4 GHz with rates up to 54Mbps


WiFi Standards

WPA (WiFi protected Access)TKIP encryption and protects against unauthorized

network access through the use of a pre-shared key (PSK)

WMM (WiFi MultiMedia)packet prioritisation that meet IEEE 802.11e

quality of service standard.Packets containing time-dependent data such as

audio or video to be sent ahead of data that can safely wait a few microseconds


WiFi Hardware

Access points (APs)PCMCIA cards/ PC cardsUSB adaptersPCI network cardsWireless routers


WiFi Applications

RetailsWarehousesHealthcareEducationhttp://www.wifinetnews.com/

News about wifi and also see if you can find out the hotspot(s) around the Stoke-on-Trent area


WiFi topology

Ad HocWithout use of Access PointPeer-to-peer style communicationRecommended 3 or less users per channel

InfrastructureCommunication each other devices by the use of

Access Point About 10-30 users per access point






Ad Hoc vs Infrastructure

Ad Hoc can be setup instantly for temporary solution

Scalability is limited to Ad HocCoverage ReliabilityEfficiency


Wireless LAN


Security choices

Network security ensures the communications and files are protected

How important of the security depend on how you want to use the network.Browsing internet and mp3 streaming may not need a

securityInternet shopping or purchasing will use SSL security

There are several way to protect your data confidentiality while transmitting

In WLAN, you can change your SSID, WEP or WPA or latest technology WPA2


Wireless surfing

Common knowledge that some users use someone else’s network connection to use the Internet “piggybacking”Hi-gain antenna example that I use

How do you know someone is using you?If infrastructure – you don’t – would have to look at router

logsAd-hoc – shows in connections window

How do they know you are not using them in return?


WEP

Wired Equivalent PrivacyEncrypt data over the radio wavesImplemented in MAC layer – NIC encrypt the frame

before transmitUsing 64bits or 128bits encryption keysShared secret keyYou need to provide 40 bits (10 digit Hex) or 104bits (26

digit Hex)24 bits Initialisation Vector (IV) for generating key

sequence


Limitation of WEP

Share, static keysWEP only encrypt frame within wireless

station but not within wired networkLimited IV numbers and may increase

collision - IV repeats after sending 26GB. Recovery attack - the data can be

manipulated after a few hours by tracking repeating IV


WPA and WPA v2

WiFi Protected AccessDifferent key for each user48 bit IV – defeats recovery attack on WEPUse Temporal Key Integrity Protocol (TKIP)

which dynamic change keys on transmissionMore information on http://www.wifi.org


Summary

Security is the main issues in wireless communications

Still in the development to increase the privacy

Next tutorial you will see wireless security in action

Documents

Version 1.1 2006Slide 1 Format of lecture Introduction to Wireless Wireless standards Applications Hardware devices Performance issues Security issues