Airgo Networks took the occasion of last Friday’s vote by the IEEE 802.11n Taskgroup to proceed to the "letter ballot" phase of the standardization process, to go public with the developing standard’s little secret. The firm claims that the "802.11n Draft 1.0 does not provide for interoperability with nearby legacy 802.11b/g networks".

"Specifically, if ’Draft N’ or ’N Ready’ products are released to market based on Draft 1.0 of the standard, they will severely degrade - or even disable - nearby 802.11b and 802.11g networks," Airgo said.

The firm’s announcement is the first public acknowledgment by a chipmaker of behavior that TomsNetworking documented two months ago in its review of Netgear’s RangeMax 240. The Netgear product is based on Airgo’s third-generation chipset that uses a 40 MHz wide band to achieve greater than 100 Mbps of application-level throughput. The problem has also been confirmed by other reviewers in Linksys’ WRT54GX4 "SRX400" products, which also employ the Airgo third-generation chipset.

Although Airgo does not claim 802.11n draft compliance for its chipset, all upcoming "draft 11n" chipsets from Atheros, Broadcom and Marvell will employ similar mechanisms that use 40 MHz of bandwidth to achieve raw throughput as high as 600 Mbps.

The good news is that, according to Airgo, some 11n Taskgroup members decided to immediately form a committee to address the issue in the 1.0 draft. The committee is being chaired by Cisco and Motorola, and will begin bi-weekly conference calls next week.

Airgo, however, also took the opportunity to cast some F.U.D. upon the high-speed WLAN waters, saying that fixing the problem "will require silicon changes to the "Draft 1.0" chips". This is a direct attack upon claims by Atheros, Broadcom and Marvell that their upcoming "draft 11n" devices will be firmware upgradeable to the final 802.11n standard. Airgo has maintained a "go slow" stance regarding its current chipsets, saying it is too early to make upgradeability claims.