Should you worry about the interference effects of "Super G"?

Tests indicate 108M bit/sec products can degrade 802.11g performance

Industry analysis by expert Joanie Wexler, plus links to the day's wireless news headlines

OK, you've read the headline. So let's get the caveats out of the way first.

Any network environment is going to have lots of variables so absolutes in networking decisions are few and far between. Most of what you read has to be considered in the context of your own environment and your own beliefs about the "right" way to do networking. Particularly when it comes to wireless networking, you're well advised to do some of your own benchmarking before making big decisions. What works well under a certain set of circumstance may not match your own.

This having been said, the wireless network environment has aspects to it that you don't even have to consider in the wired world. One is that radio-frequency signals don't stop and start at strictly defined points, as traffic traversing a cable attached to two ports does. Another is that radio signals radiate in three dimensions, not just back and forth on a cable. These traits mean that wireless networks can unexpectedly affect the workings of other wireless products - whether they are yours or someone else's.

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OK, you've read the headline. So let's get the caveats out of the way first.

Any network environment is going to have lots of variables so absolutes in networking decisions are few and far between. Most of what you read has to be considered in the context of your own environment and your own beliefs about the "right" way to do networking. Particularly when it comes to wireless networking, you're well advised to do some of your own benchmarking before making big decisions. What works well under a certain set of circumstance may not match your own.

This having been said, the wireless network environment has aspects to it that you don't even have to consider in the wired world. One is that radio-frequency signals don't stop and start at strictly defined points, as traffic traversing a cable attached to two ports does. Another is that radio signals radiate in three dimensions, not just back and forth on a cable. These traits mean that wireless networks can unexpectedly affect the workings of other wireless products - whether they are yours or someone else's.

This is one concern that has come up surrounding products based on Atheros' so-called "Super G" chip, a derivative of the 54M bit/sec 802.11g standard that "bonds" channel 6, half of channel 1 and half of channel 11 together to give you higher theoretical throughput (108M bit/sec).

The Tolly Group has tested the effects of Super G products on nearby 802.11g standard-compliant products as well as in networks with multiple Super G products only. The impact of the degradation in these tests is significant and worth noting.

Note that most of Atheros' Super G products are currently supported in consumer-class products. One reason is that consumers are very interested in downloading multimedia entertainment - and the higher speeds boost that ability.

But Super G is not an industry standard. If you don't want to use standards and not doing so affects only you, so be it. On the other hand, since wireless can affect your neighbors - whether in a house, apartment, condo or office suite next door - is installing it the right thing to do?

The Tolly Group plans to release a formal report later this month. It was commissioned to run the Super G tests by cutthroat Atheros competitor Broadcom (which admits having some skin in the game here). So there is an agenda afoot other than the good of the industry. But that doesn't mean that you shouldn't be informed about this issue, which has some teeth.

When the Tolly Group tested a single Broadcom-based Belkin F5-D7320 802.11g standard-compliant access point by itself, its average aggregate throughput was 22.96M bit/sec. When an Atheros-based NetGear WGT624 access point and client card were running 30 feet away from the Belkin, though, the Belkin's performance dropped nearly 95%, to 1.27M bit/sec.

Tolly Group head Kevin Tolly says his organization used the NetIQ Chariot traffic simulator to conduct the tests and that the tests were repeated 33 times - three times on each of 11 channels. Then, he says, the organization spot-tested the Super G impact on the Belkin device at 60 and 75 feet with the same result.

Joanie Wexler is an independent networking technology writer/editor in Silicon Valley.