Charles,
I'd be interested to know which client/drivers you've already tested
this with. Maybe others have some as well to add to a list of either
working or not. Thanks,
--
Don Wright
Brown University
CIS - NTG
On 9/10/08 10:41 AM, "Charles Spurgeon" <[EMAIL PROTECTED]> wrote:
> FYI. This documents something that we have stumbled over with UNII-2e
> channels and is a "heads up" for anyone running Cisco LWAPP gear and
> using the auto channel selection component of RRM ("Dynamic Channel
> Assignment" (DCA) in Cisco-speak).
>
> The Cisco WLC release notes for v4.1.185.0 have an important caveat
> (CSCsi86794) that describes the behavior of DCA and the UNII-2
> Extended channels (UNII-2e).(1) For some reason this caveat is missing
> in 4.2.130.0 release notes, while the DCA issue still appears to be
> present in that code. (Based on the text in the 4.1.185.0 release
> notes the UNII-2e support appears to have first shown up in
> 4.1.171.0.)
>
> Briefly, Cisco has added support for the UNII-2e channels to the
> wireless lan controller and LWAPP APs, and these channels are
> automatically enabled for use by DCA.
>
> As a result of the new support, AP radios may be automatically
> assigned by DCA to one of the UNII-2e channels. We found several
> radios in our system where that had happened.
>
> Unfortunately, none of the 802.11a clients that we have tested know
> about the UNII-2e channels, and therefore most (all?) 802.11a clients
> cannot associate with AP radios that have been assigned to the UNII-2e
> channels. An AP radio on one of those channels is no longer available
> to dot11a clients and your wireless coverage will have holes in it
> even though the AP is up and system monitors are happy.
>
> If the client NIC has an 802.11an radio then it may have support for
> the UNII-2e channels. You would need to test against an AP radio set
> to one of the UNII-2e channels to find out, since the vendor docs that
> we have looked at don't tend to have any documentation about the
> presence or absence of UNII-2e support.
>
> To avoid this issue, Cisco's release notes tell you to disable the
> UNII-2e channels in DCA. However, the release notes incorrectly tell
> you to also disable channel 149, which is NOT one of the UNII-2e
> channels. Instead, it is one of the older channels that is supported
> by all 802.11a NICs that we've tested.
>
> If you want to avoid issues with AP radios being set to UNII-2e
> channels that are invisible to clients then you can do that by
> disabling all DCA channels in the UNII-2e range of 100-140.
>
> Note that when you disable these channels using either the CLI or the
> Web GUI the AP radios must be disabled and then re-enabled to make
> that change.
>
> We would be interested in hearing about the experience at other sites
> with UNII-2e channels, especially the results of any tests of UNII-2e
> support in clients.
>
> Thanks,
>
> -Charles
>
> Charles E. Spurgeon / UTnet
> UT Austin ITS / Networking
> [EMAIL PROTECTED] / 512.475.9265
>
> (1) The UNII-2e channels appear to be relatively recent
> additions. This Cisco doc mentions them in the context of DFS support
> requirements: http://tinyurl.com/yq7y9r
>
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