1. 1 Wireless LAN Technology for SOHO Instructor: Professor Mort Anvari Presented by: Yanfeng Wang Jie Lin

2. 2 Road Map What is a wireless LAN Advantage of wireless LAN Hardware Requirement WLAN Model Standards Issues to Be Solved Future

3. 3 What Is A Wireless LAN (WLAN)? A Wireless LAN is a LAN without conventional network cabling. It is a flexible network that can either replace or extend a wired LAN to provide added functionality. It relies on radio frequencies (RF) to transmit and receive data between computers.

4. 4 Advantages of WLAN---Mobility Users can move around and still remain connected to the network –It gives users greater flexibility to move computers anywhere in home or office and still have them be networked. –Networking computers in different rooms or on different floors might need the convenience of a WLAN.

5. 5 Advantages of WLAN: Reliability Cable fault is completely eliminated! –Wired network maybe reliable, but cable faults is still a problem, which can cripple network traffic, and tracking them down can take many hours. Cables break makes metallic conductors rust or allow water to enter Staff members accidentally cut cables Workers do a shoddy job of splicing

6. 6 Advantages of WLAN: Cost Sometimes cabling is too costly or impossible –cabling between buildings can be expensive –impossible due to structural hurdles or digging restrictions Long-term cost concerns: Recabling can be expensive, time-consuming, disruptive. –Company Reorganization moves employee around, reconfigure offices, and add new buildings. –Home Renovation:Children move out, Adult switch around, add rooms or initiate remodeling projects.

7. 7 A Wireless LAN

8. 8 Hardware Requirement Wireless NIC and PCMCIA Wireless Hub (Access Point) Wireless Bridge

9. 9 Wireless NIC/PCMCIA –Wireless adapters are made in the same form factors as their wired counterparts - PCI, PCMCIA, and USB. –Adapters for wired LAN provide the interface between the network operating system and the wire. –Adapters for WLAN provide the interface between the network operating system and an antenna, to create a transparent connection to the network.

10. 10 Wireless NIC/PCMCIA

11. 11 Wireless Hub (Access Point) Access Point is the wireless equivalent of a LAN hub. It use antenna to receive, buffer and transmit data among the member computers of a WLAN An Access Point can be connected with the wired backbone through standard Ethernet cable.

12. 12 Wireless Hub (Access Point ) Like the cells in a cellular phone network, multiple Access Points can support roaming from one Access Point to another as the user moves from area to area Access Points have ranges from 20 meters to 500 meters A single Access Point can support 15 to 250 users, depending on the technology and configuration.

13. 13 Wireless Hub (Access Point) It is easy to scale up WLANs by adding more Access Points, which decreases network congestion and enlarges the coverage area. Large facilities require deployment of multiple Access Points to create overlapping cells for constant connectivity to the network.

14. 14 A Wireless Hub (Access Point)

15. 15 Wireless LAN Bridge Outdoor LAN bridges connect LANs in different buildings. –highways –bodies of water It provides a less expensive alternative to recurring leased-line charges. –It supports fairly high data rates and ranges of several miles with the use of line-of-sight directional antennas.

16. 16 Wireless LAN Bridges

17. 17 WLAN-Peer to Peer Model It consists of two or more PCs equipped with wireless NICs, but with no connection to a wired network. It is principally used to quickly and easily set up a WLAN where no infrastructure is available –a convention center –a trade fair No Access Point is needed.

18. 18 Peer to Peer Model

19. 19 WLAN-Client/Server Model It typically consists of multiple computers (both the servers and the clients) equipped with wireless NICs and an Access Point that acts as a traffic center of the WLAN

20. 20 Client/Server Model

21. 21 Mixed Model Wired LAN and wireless LAN are not mutually exclusive. Wired LANs and wireless LANs can join seamlessly.

22. 22 Mixed Model

23. 23 Price: Current Not for shallow pockets Expensive compared to wired LAN –Wireless NIC:$40 up –Wireless PCMCIA:$100 up –Wireless Hub:$200 up Don’t worry, it is quickly dropping!

24. 24 Where To Buy? Electric Appliance Retailers: –BestBuy, Circuit City, CompUSA Online Retail Stores: –buy.com, egghead.com Manufacturer’s Online Store –sohoware.com, cisco.com

25. 25 Major Hardware Manufacturers Intel Cisco 3Com Lucent Netgear SOHOWare

26. 26 Standards---802.11 Like all IEEE 802 standards, the 802.11 standard focuses on the bottom two levels of the ISO model, the physical layer and data link layer. Any LAN application, network operating system or protocol, including TCP/IP, will run on 802.11 compliant WLANs as easily as they run over Ethernet.

27. 27 Potential for Improvement Predictability: –Walls, large appliances, and other obstacles can interfere with the propagation of radio waves, degrading the network’s performance. Security: –with the network access code, anyone within the broadcast area can eavesdrop on network communications. Speed: –The current speed of 1Mbps to 11Mbps makes it difficult to stream video across wireless network and get good results. –Results with audio are better, but still not optimum.

28. 28 Future Growth 75 percent of large organizations are evaluating WLANs More than 90 percent of all communications traffic consists of data and not voice, which represents a huge potential of growth for wireless data communication. Laptops now make up about 25 percent of corporate purchases (Intel Corporate Market Research, 2000). Analysts agree that the WLAN market is set to reach $1.6 to $2.2 billion by 2005.

29. 29 Summary It is there! It is nice! It’s cost is quickly dropping! It’s the direction of the future!