July 15, 2000  

Wireless Standards Slow To Market

Submitted by Stephen Lawton, Editor-In-Chief, MicroTimes

Networking vendors love to tout how standards eliminate the IT manager's concern for interoperability. Realistically, of course, the job falls to integrators to make disparate products work together, and sometimes that promise of interoperability is one that cannot be kept.

Despite the fact that the IEEE 802.11 wireless-networking standard has been around for some 18 months, vendors have been less than enthusiastic to complete product interoperability testing at the 2-Mbits/sec speed.

Instead many are pushing ahead to the next level, 11 Mbits/sec, which will put wireless networking at roughly the same raw throughput speed as traditional 10-Mbit/sec wired Ethernet. A new proposed standard, dubbed 802.11b, addresses this 11-Mbit/sec technology in the 5-GHz range; the 2-Mbits/sec specification is now referred to as 802.11a.

Even with a standard, customers need to be careful when they select their wireless networks. The 802.11 specification defines three different physical-layer connections for the spread-spectrum links--one for infrared and two for radio. The radio designs are Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping (FH). The DSSS approach spreads a signal over a 22-MHz range, whereas the FH technique transmits the signal over a single, narrow band.

If a company installs a DSSS network, it must stay with that technology, even though FH also is defined in the specification, as vice versa. That limitation alone places limits on interoperability.

Almost a dozen companies representing the DSSS and FHwireless-networking technologies currently are testing their 2-Mbits/sec products at the Wireless LAN Interoperability (WLI) Forum in Sunnyvale, CA, for standards compliance and interoperability. Once the tests are completed later this summer, the forum is expected to release a document that outlines which vendors' products were tested and how well they work together.

This work is significant because the University of New Hampshire's compatibility laboratory, which tests for standards compliance, does not offer recommendations as to which vendors' products will work with other vendors' products, notes Lynn Chroust, product marketing director at Proxim Inc. in Sunnyvale, CA. The WLI Forum, however, will provide that information, which is critical for integrators who are configuring a network for a client.

In the real world, however, customers still are finding single-vendor installations more reliable than either trying to expand an existing wireless network with a second vendor's products or building a multivendor installation from scratch. Although basic interoperability exists with all of the optional features turned off, devices with extra functionality find it difficult, if not impossible, to communicate in a multivendor environment.

These optional features include such items as Wired-Equivalent Privacy (WEP), the only security protocol defined by the 802.11 specification, and power management. "WEP is an option, but if [a vendor] doesn't offer it, the network is naked to the world," says Chroust. And power management is important, because without it a notebook computer's battery can drain literally in 15 minutes or so without the feature activated.

Full interoperability, which would include such capabilities as using a notebook computer with one vendor's PC network interface card installed in a building with a different vendor's access points, might not occur for some time, if ever, adds Terry Manning, sales and marketing vice president for Boston-based Zoom Telephonics Inc. "Driver issues and the three choices for doing wireless communications are key sticking points for full interoperability," he notes.

While standards-based products garner considerable attention, RadioLAN, the Sunnyvale, CA-based supplier of proprietary 10-Mbit/sec wireless networks, continues to buck the gang mentality. Rather than worrying about low-speed, 2-Mbit/sec connections, RadioLAN offers much higher speeds. But the tradeoff is in standards, as the size of its wireless cell can be as much as 20-percent smaller than the cell size of an 802.11-compliant cell.

Whether you work with the standards or ignore them, it just isn't all smooth sailing yet in the mobile arena.


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