WLANs: More than a Cable-Pulling Alternative

New technology offers standardization, reduced cost, and increased speed

Pulling cable is a large fixed cost in setting up and deploying a new network installation. In the early 1990s, Category 5 UTP cable commanded a premium price and most companies didn't need it. However, many companies installed Cat 5 UTP cable because they didn't want to expend the time and expense of pulling cable later. An alternative to cable pulling is the wireless LAN (WLAN), which became available in the mid-1990s. But at that time, WLANs were slow, proprietary, and very expensive, which seriously limited their use outside vertical market environments.

Cabled networks gradually became easier to install, offered increased speeds, and became commodity hardware. Wireless networks continued to advance with increased network speeds but remained too expensive and too proprietary for most companies. Then, in 1997, the IEEE ratified the 802.11 specification for wireless network implementations in the hope of creating a standard.

The 802.11 specification was promising because its design provided interoperability between vendors that chose to use the same Physical Layer: either Direct Sequence Spread Spectrum*DSSS*or Frequency Hopping Spread Spectrum*FHSS. Both technologies are radio frequency (RF)-type systems.

In the 802.11 specification, DSSS supports speeds up to 2Mbps with a fallback of 1Mbps if the transmission is too noisy, and FHSS supports a speed of 1Mbps with the ability to transmit at 2Mbps if the transmission is exceptionally clean. DSSS has the advantage of higher speeds in most situations; however, FHSS can cram more LANs on the same frequency and offers a higher level of native security because the transmission frequency constantly changes.

But even with a ratified specification, the WLAN remained a bit player, primarily because the 802.11 specification's speed was a step backward in the network world, which had moved well beyond 2Mbps networks. And even with a standard in place, cost remained a huge hurdle to companies considering wireless network adoption. Individual NICs cost as much as $500, and each user group also needed a cabled network connection to a wireless hub (called the Access Point), which usually cost about $1000. Low production volumes and lack of vendor cooperation in assuring potential users that their devices would interoperate kept the costs of wireless networks high. Meanwhile, wired product vendors dropped prices exponentially.

The slow speed of WLANs made them tough for wireless vendors to sell to mainstream IT departments throughout the 1990s. However, certain vertical markets, such as warehouse inventory management and hospital patient management systems, adopted wireless networks and tablet-based com-
puting to deal with the paperwork load. To these users, wireless networking at any speed was a godsend.

Remember that speed is relative. If you tell a network administrator that you're installing a 2Mbps network, he or she will tell you that you're out of your mind. If you tell him or her that you're installing a 2Mbps Internet connection, he or she will kiss your feet.

But wireless networking advocates understand that speed sells networking devices, so in 1999 the IEEE released the 802.11b High Rate specification. This wireless network specification brings DSSS to 11Mbps, which approximates the 10Mbps that UTP Ethernet in current wired networks achieves. With a peak rate of 11Mbps and fallback rates of 5Mbps, 2Mbps, and 1Mbps, most wireless networking products today are 802.11b-compatible. The specification also calls for compatibility with wired Ethernet products through an Access Point or bridge.

The 802.11b specification also defines how wireless networks can implement the Wired Equivalent Privacy (WEP) standard to achieve data security. WLANs that implement and enable the WEP standard require the encryption of all network traffic.

But the question of interoperability remains. The 802.11 specification leaves room for interpretation, so a product can be 802.11-compliant and still be incompatible with other vendor's 802.11-compliant products. The University of New Hampshire InterOperability Lab (IOL) works with wireless vendors to ensure product compliance with the 802.11 specification and to ensure that products can interoperate with other compliant products. For more information about the IOL's work, testing methodologies, and vendor results, visit the Web site at http://www.iol.unh.edu/
consortiums/wireless/.

Another organization concentrates strictly on interoperability. The Wireless Ethernet Compatibility Alliance's (WECA's) goal is to promote interoperability between its members' products. This alliance offers Wireless Fidelity (WiFi) logo certification, which lets consumers pick up any combination of certified products and know that the products will work together. At a NetWorld+Interop 2000 Las Vegas booth, about a dozen vendors demonstrated WiFi-certified products successfully interoperating. For more information about WECA, see http://www.wirelessethernet.org/.

Is wireless networking the right solution for you? I spoke to network administrators from many different lines of business, and the general consensus was that they consider wireless networking only in situations in which running cables isn't possible or is too expensive. And even then, administrators use wireless networking to support only a few users.

Because the cost of 802.11b solutions is falling as the number of vendors increases, WLANs have become a suitable solution for a variety of user types. Visiting a remote office and finding a free network port and cable can be a problem, especially if your company has a large number of traveling personnel. A simpler solution is to equip each of your company's sites with a wireless Access Point and give traveling users appropriate NICs. Then, users no longer need to hunt for cables or make sure the network port is active.

You can also use wireless NICs to let users roam within the main company office. Because common devices such as the 3Com PalmPilot are able to accept PC Cards, your local users can use these devices to update schedules and access contact information from anywhere in the building or bring a notebook computer into a meeting to take notes.

The possibilities that WLANs bring to your user community are extensive. As the cost continues to decline, WLANs might become the solution of choice for small office/home office (SOHO) users and consumer users. You can be certain that corporate executives who can put their notebook in hibernate mode before they leave the office, then turn the notebook on at home and already have an Internet connection will be happy executives.

I'll be giving wireless networking a shot in my home office, despite my Cat 5 UTP cable. What about you?