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Wireless LAN Technology for SOHO

Instructor: Professor Mort Anvari

Presented by: Yanfeng Wang

Jie Lin

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Road Map

• What is a wireless LAN

• Advantage of wireless LAN

• Hardware Requirement

• WLAN Model

• Standards

• Issues to Be Solved

• Future

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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.

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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.

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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

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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.

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A Wireless LAN

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Hardware Requirement

• Wireless NIC and PCMCIA

• Wireless Hub (Access Point)

• Wireless Bridge

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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.

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Wireless NIC/PCMCIA

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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.

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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.

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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.

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A Wireless Hub (Access Point)

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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.

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Wireless LAN Bridges

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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.

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Peer to Peer Model

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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

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Client/Server Model

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Mixed Model

• Wired LAN and wireless LAN are not mutually exclusive.

• Wired LANs and wireless LANs can join seamlessly.

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Mixed Model

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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!

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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

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Major Hardware Manufacturers

IntelCisco3ComLucentNetgearSOHOWare

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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.

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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.

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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.

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Summary

• It is there!

• It is nice!

• It’s cost is quickly dropping!

• It’s the direction of the future!