1. Wireless Networking
Chapter 16

2. Objectives
• Explain wireless networking standards
• Describe the process for implementing Wi-
Fi networks
• Describe troubleshooting techniques for
wireless networks

3. • Historic/Conceptual
– Wireless network uses radio waves as the media
• Convenient
• Sometimes the only network option
• Same OSI layers as wired networks
• Same [upper layer] protocols
• Different methods for accessing the media
• IEEE 802.11 wireless Ethernet standard
– Wi-Fi
– Most common implementation

4. • Wi-Fi Standards
– Wi-Fi IEEE 802.11
• 802.11a
• 802.11b
• 802.11g
• 802.11n

5. • Certified by Wi-Fi Alliance
– 300 member companies
– Design and manufacture wireless networking
products
– Certification should ensure compatibility
between manufacturers
– Troubleshooting section at end of this chapter
brings out proprietary nature of some devices

6. • 802.11
– Standards define how wireless devices
communicate
– Some define how to secure communication
– Each sub-standard has name of a IEEE
subcommittee
• Wireless Fidelity (Wi-Fi)

7. • Wireless Network Modes
– Ad hoc mode
• Also called peer-to-peer mode
• Uses a mesh topology
• Independent Basic Service Set (IBBS)
– Two or more wireless nodes communicating in ad hoc mode
• Infrastructure mode
– Uses one or more access points
– Similar to a wired star topology
– Basic service set (BSS)
• Served by a single WAP

8. • CSMA/CA
– Carrier sense multiple access/collision avoidance
(CSMA/CA)
– Access method to allow multiple devices to share
network media
– Review how CSMA/CD works for wired networks
• Each device listens on media
– If no or low signal, media is free
– If signal above a threshold, media is busy
• If media is busy, device waits the length of the current
frame plus the interframe space (IFS) period

9. • Wireless Networking Security
– Problem
• Easy-to-install devices have no default security
• Network data packets are in radio waves
– Easy to capture
– Easy to read

10. • Three wireless security methods
– MAC Address Filtering
• Limits access to specific NICs
• “Accepted users” list of MAC addresses
• List in table stored in WAP
• Data packets with other MAC addresses are rejected

11. – Wireless Authentication
• Only users with proper credentials have access
• Can use a centralized security database (like Active
Directory)
• Requires extra steps for wireless users

12. – Data Encryption
• a. Data Encryption Using WEP
– Wired Equivalent Privacy (WEP)
– 64- or 128-bit encryption algorithm
– Scrambles data packets
– Problems
» Easily cracked
» Only works on two lowest OSI network layers