I own a Cisco, D-Link, Linksys, Netgear, Nortel, or SMC a/b/g wireless card and am having throughput (slow connection) problems

There has been a problem discovered with certain cards made by these manufacturers.

Who is affected:

Certain 802.11a/b/g client cards that utilize a Dual Radio Atheros Integrated Circuit Design. Cards that have been identified with the problem include:

• Cisco AIR-CB21AG-A-K9
  Update: The problem with the Cisco AIR-CB21AG card is fixed in hardware rev 03 (74-3481-03) and above.
• D-Link DWL-AG650 (HW Rev 3)
• Linksys WPC-55AG V1.1
• Netgear WAG511 V2
• Nortel MU2202
• SMC 2336W-AG

***Note this impacts many 802.11 a/b/g combination cards not 802.11 b/g or 802.11a cards.

Problem Symptoms:

Users whose hardware is affected by this problem will experience degraded connectivity (Signal Strength / Throughput) when associated to an Access Point (AP) operating on Channel 11. There is no issue when associated to AP's operating on Channels 1 and 6.

There is an approximate 50% reduction in data throughput and available bandwidth on Channel 11 (and 10) compared to other 802.11 b/g Channels (1?8). Note: Channel 9 is marginal based on our testing.

The effective range, when using the affected cards, is significantly reduced and varies by the type of building / RF environment.

Since the design of wireless networks requires the predominate use of channels 1, 6, and 11, it can be assumed that a significant percentage of wireless areas on campus and elsewhere use Channel 11.

This means if you are using an affected card in a wireless area being supported by an AP using Channel 11, you may experience a significant reduction in the speed of your connection. If you are trying to access the network in the outer area(s) of coverage, you may not be able to connect.