SZ auto channel preference for UNII-2e

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  • Updated 1 year ago
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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.
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Robert Lowe

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Posted 1 year ago

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Michael Brado, Official Rep

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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.
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Michael Brado, Official Rep

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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.
https://support.ruckuswireless.com/answers/000004448
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Robert Lowe

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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. 
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Michael Brado, Official Rep

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