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SZ auto channel preference for UNII-2e

Contributor III
Hi Guys, so i have a ticket open with support but thought i would ask here for anyone who has experienced a similar issue:

I have recently installed a SZ100 (first one) which is sat in a DC and have remote AP's from multiple sites connected to it over MPLS. The issue that I am seeing is that i have auto channel set (background scanning) and 99% of the AP's installed choose a UNII-2e channel rather than a UNII-1 or even UNII-2. I have a mix of clients and am concerned that not all will support DFS channels but i dont want to limit my deployment to 4 channels. For example; one site has 21 AP's, 20 of them have a UNII-2e channel and only 1 has selected CH36. I have done an Ekahau walk and there is virtually no 5GHz noise so this must be a software 'feature'. Same at other site too with a couple of AP's. 

If i change an AP group to UNII-1 then all AP's choose a UNII-1 channel and operate without issue.

So my concern is that there is an issue with software that means AP's will prefer UNII-2e channels before any other.

Esteemed Contributor II
There is no known issue.  Many APs will begin operation on channel 149 (by default), and change channels
if interference thresholds are met.  Note: If your APs are not close enough to interfere with each other, they
may select the same (usually default) channel, and this does not indicate a problem.

And you can use "blacklist" commands to be sure your APs avoid all DFS channels if you wish.
Find guidance in KBA-4448:  How to blacklist 5G UNII-2 channels on vSCG/SCG managed APs.

Thanks Michael, AP's begining operation at Ch 149 seems very strange to me and I can say its not something I have experienced on the ZD platform.

Based on the fact that UNII-1 channels are the 'mandatory' channels for 5GHz operation I would have thought all 5GHz radios would have a desire to accommodate these channels in a quite environment before any other. 

That channel 149 first might have been default first channel behavior for an outdoor AP if I remember correctly.