[CUWiN-Dev] noise on channel 11 -- potential atheros problem:

[Sascha Meinrath]

FYI:

Date:    Tue, 22 Feb 2005 23:15:55 -0600
From:    Scott Genung <sagenung at ILSTU.EDU>
Subject: noise on channel 11

All,

For several months, we've been chasing an elusive issue relating to 
connectivity problems that many of our users have when accessing 2.48G 
coverage areas on channel 11. In short, their wireless cards would fail to 
associate with these sites and AirMagnet would report excess noise in 
these environments. Spectrum analyzers showed no evidence off excessive 
noise on this channel in any coverage area so we started to suspect that 
the noise was being reported erroneously.

Then recently, we found a resource within Cisco that made us aware of a 
problem with a recent version of the Atheros chipset used by many 
manufacturers including Cisco, Netgear, D-Link, HP, IBM, NEC and Toshiba. 
I have not been able to find any additional information about this issue. 
Neither Cisco nor Atheros seem to not have any publicly available 
documentation on this subject.

We did find that the University of Tennessee makes a vague reference to 
this issue in their wireless FAQ. See below:

http://oit.utk.edu/helpdesk/faq.php?section=11#q126

So if what we're hearing is true, it's quite unlikely that we're the lone 
ranger (although sometimes I wonder). Have others experienced this issue? 
Does anyone have any documentation that they can share on this issue? Are 
there other wireless NICs (beyond what is mentioned above) that we should 
make users aware of? Are these vendors releasing any firmware updates to 
resolve this issue (Cisco is just RMA'ing these cards).

Scott Genung
Manager of Networking Systems
Telecommunications and Networking
Illinois State University
124 Julian Hall
Normal, IL 61790-3500

Phone: (309)438-7258
Web: http://www.tel.ilstu.edu