Commentary: Wireless LANs not for everybody

Many enterprises planning to put up a new building wonder whether they should make the LAN completely wireless. The answer is an unequivocal "no."

	See news story: Start-up aims for A-list status in wireless LANs

Wireless LANs are still 10 times slower than modern switched Ethernet LANs and are more than twice the price, and they cannot deliver the total site capacity of their wired Ethernet cousins.

In the right situations, however, it may make sense for certain enterprises to invest in wireless LANs. Enterprises should consider wireless LANs in these circumstances:

• To extend the functions of wired LANs where more workers carrying laptops and personal digital assistants demand convenient access to corporate network resources.

• To accommodate frequent physical plant additions, moves and changes that drive up the cost (and downtime) of maintaining a LAN connection.

• To accommodate intracompany site visitors and reduce the logistics and cost of getting those visitors access to their corporate network resources without having to find a spare Ethernet drop.

• To ease the frustration of getting connected to high-bandwidth networks for workers who carry their laptops between company offices, homes and, increasingly, public places such as airports, hotels and convention centers.

The two choices for wireless LANs are those built on the 802.11b and 802.11a standards set by the Institute of Electrical and Electronics Engineers (IEEE).

Products designed to the 802.11b standard now provide access speeds as high as 11mbps for less than $300 per node.

Security and quality of service are not defined to acceptable levels in 802.11b. Quality of service is required to support telephony and video-streaming applications where priority must go to voice and video packets.

Meanwhile, the 802.11 standard does not support roaming between bridged or routed LAN segments. Not surprisingly, within a LAN segment, various technology companies offer differing implementations of roaming between two access-point coverage areas. After years of turning a deaf ear to the requirements of the market, the IEEE has formed a working group (802.11f) to provide for a roaming standard. That effort, and one to improve quality of service and security, will perhaps yield IEEE approvals by the end of this year.

The pros and cons of 802.11a
The specification for 802.11a at 5.2GHz permits wireless LANs such as those addressed by Atheros Communications to move away from several sources of interference that occur in the 2.4GHz range--primarily Bluetooth cordless phones and microwave ovens. However, Gartner finds at most only 20 percent degradation, and Bluetooth is having birthing pains and will take two years before enterprises start to adopt it in earnest.

Atheros uses a proprietary mode, which will provide extra bandwidth but will also take its system off the 802.11a standard.

Transmit-power control enables a wide variety of cell sizes, permitting some applications to enjoy greater frequency reuse (which is important in high-density applications, such as stock exchanges). Despite technical enhancements that attempt to ensure transmission characteristics similar to those for 2.4GHz, maintaining a comparable footprint will perhaps require 50 percent more access points--and perhaps four times more than for 802.11b. 802.11a network interface cards and costs per access point may become comparable to 802.11b costs by year's end 2002.

The major hurdles to the full adoption and deployment of 802.11a are cost, power consumption and the use of the 5.2GHz band, or possibly the 5.8GHz band. Because satellites share it, the 5.2GHz band is certified only for indoor use, so it could not serve, for example, an outside depot.

Worldwide approval of the 5.2GHz radio band to be used for wireless LANs is missing. Europe has approved 5.2GHz only for Hiperlan 2, but with that specification faltering, European regulators will likely approve the use of 802.11a wireless LANs. Japan has approved only about the lower half of the band, which will reduce throughput and the number of users supported.

It will take time for companies such as Atheros to ramp up production to meet demand from large enterprises. While doing good work, these companies may cause confusion among enterprises because they will likely delay purchases for what is now a very good standard, 802.11b.

802.11b wireless LANs are deployable today and can provide significant benefits for office mobility, for small offices or for places where it is impossible to deploy wired LANs. By year-end 2002, 802.11a products will be unleashed at roughly today's costs.

(For related commentary on wireless LANs, see TechRepublic.com--free registration required.)

Entire contents, Copyright ? 2001 Gartner, Inc. All rights reserved. The information contained herein represents Gartner's initial commentary and analysis and has been obtained from sources believed to be reliable. Positions taken are subject to change as more information becomes available and further analysis is undertaken. Gartner disclaims all warranties as to the accuracy, completeness or adequacy of the information. Gartner shall have no liability for errors, omissions or inadequacies in the information contained herein or for interpretations thereof.