IEEE 802.11 provides platform for new applications

When the concept of the wireless local area network (LAN) was introduced more than 20 years ago, numerous companies tried to implement its applications through the use of spread spectrum, infrared and narrowband microwave technologies based on twisted pair, coaxial cable and optical fiber. When a physical location is not required where a network must be tied down, the system is made more flexible, enabling several machines to be set up remotely anywhere within a building.

Today, the real breakthrough has been seen in the approval of the IEEE 802.11 standard, which gives a platform for new applications and chips already in the marketplace. Wireless LAN applications are best suited for universities, banks, commercial buildings and hospitals.

Spread spectrum is the most popular transmission technique for wireless LANs because it is one of the most secure, does not interfere with other services and carries a large bandwidth of data. Microwave technology’s main use is to interconnect LANs between buildings, using microwave dishes on both ends of the link but the frequency band used requires licensing by the Federal Communications Commission. Infrared LANs, which are desirable because they can carry a high bandwidth but are easily obstructed, can be set up using a point-to-point configuration where the signals are diffused by reflecting them off a surface.

Wireless fidelity (Wi-Fi) is based on an approved IEEE 802.11b High Rate standard, placing wireless LAN technology on an equal footing with 10BaseT Ethernet capabilities. The 2.4 GHz frequency and digital subscriber signaling #2 (DSSS) radio mode is already approved and being used at the 2 Mbps standard. It is important to ensure the wireless LAN products are based on this standard, thus ensuring an end-to-end secure solution. Wi-Fi gives PC users a more flexible way of working, enabling them to communicate with portable computing devices rather than being attached to a wall. It achieves the same performance as a wired 10BaseT LAN connection, offers flexibility with sustained performance in the office, provides a seamless add-on to an Ethernet intranet and gives roaming capabilities for mobile users.

Agere System’s ORiNOCO wireless line of products is one of the most popular in large corporations and university campuses, primarily because it offers both indoor and outdoor wireless communications and networking products.

AMP NETCONNECT Wireless Solutions offers both in-building and wide-area wireless solutions. In-building solutions may be entirely wireless or wireless extensions to existing cabled LANs. Wide-area solutions include buildings where a wired LAN serves most of the offices and cubicles except conference rooms or storage space, which may benefit from wireless connectivity to the rest of the network. The new wireless services will enable customers that need high-speed, short-range communications links to successfully implement wireless connectivity between or within offices.

“One of the most desirable features of wireless LANs is that you can still be at Ethernet speeds but have the ability to be mobile,” said Tom Janning, director of product management for AMP NETCONNECT Wireless Solutions. “It is a cost-effective solution to implement wireless technology in a building. These new wireless communications solutions represent an alternative to underground or overhead cabling or leased lines with recurring monthly fees. We have roam-about software that requires more access points to be added to a building but offers better coverage.”

The major problem with wireless LANs is ensuring that the network is secure from intruders. Since it is difficult to restrict physical access, and radio signals can propagate outside office buildings, it is possible for an intruder to attack a wireless network from an outside location. Without proper security measures in place, remote offices are vulnerable to hackers, viruses and intruders. A denial-of-service attack could be launched against a wireless LAN by deliberately causing interference in the same frequency band as the wireless LAN operates. This would cause availability problems, keeping the authorized users from using the network.

One form of wireless LAN security is authentication management, which involves setting a password at the access point. This ensures that only wireless devices configured with the same series are permitted to join a network through that access point.

Another solution is the addition of a data encryption chip, which prevents the data from being decoded and intercepted. Encryption is the real key to worry-free security in the world of wireless LANs. A wireless network protected by good encryption can be considered as secure as its wired LAN counterparts. EC

SPEED is a freelance writer based in Weymouth, Mass. She can be reached at 617.529.2676 or kkspeed@aol.com.