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 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
