Life in the Slow Lane

Your wireless LAN network is only as fast as the slowest client connected to an access point, which means that right now your shiny new 802.11g card could be idling at 1 Mbit/s rather than racing ahead at the 54 Mbit/s it's supposed to achieve.

That’s the finding of a new report from the Tolly Group, commissioned by wireless LAN chip startup Engim Inc.. The Group tested the performance of the interoperable 802.11g (54 Mbit/s over 2.4GHz) and 802.11b (11 Mbit/s over 2.4GHz) standards when used together over a single-channel access point.

The report says that the effects of just one minimum data rate client connected to an access point -- such as an 802.11b PDA -- could bring a single-channel 802.11g network down from 54 Mbit/s to close to 1 Mbit/s.

“It’s much like being on a single-lane road: You’re in a Porsche but you’re stuck behind a garbage truck, you can only go as fast as the garbage truck,” says Scott Lindsay, VP of marketing at Engim [ed. note: my other laptop’s a Porsche?].

Lindsay thinks that many IT managers don’t understand this aspect of WiFi yet, adding that even Engim was shocked -- shocked! -- by the end results of the test.

“Most IT managers, they see 54 Mbit/s on the NIC card box and that’s what they expect,” Lindsay notes.

Naturally, Engim reckons it has the solution to the data rate problems with its multichannel chipset that can support different-speed clients on a different radio streams (see Engim Drives Multi Chipsets for more on how this stuff works).

”It's more like being on a three-lane highway,” says Lindsay, doggedly determined to squeeze every ounce of life out of his poor, tortured simile.

Except that this “highway” is not yet completed. Products using the Engim chipset aren’t expected on the market until the third or fourth quarter of this year (see Accton Fires Up Engim). And another startup -- Airgo Networks -- is working on a similar high-capacity chipset (see Airgoooooooooooo! ).

So what’s a poor IT manager supposed to do in the meantime? Well, quality-of-service extensions to 802.11 can provide a partial answer to the speed trap.

”What they could do is tag different traffic streams as long they support some kind of QOS,” says Lindsay. Then the system could schedule transmissions so that the fastest clients go first, rather than getting hung-up behind the slowcoaches.

New centralized wireless LAN management players like AirFlow Networks and Meru Networks Inc. have offered variants on this kind of QOS scheme for a while, and with the increased emphasis on voice-over-WLAN (VOWLAN) applications in the enterprise market more vendors are working up these kinds of schemes -- and fast.

— Dan Jones, Site Editor, Unstrung