Controllerless Networks

Customer had an Instant 305 installed early last week. Today they informed that no one could connect to the network. I took a look remotely but couldn't find anything particular. The IAP had switched channels to avoid radar. Spectrum monitor didn't show any interference or raised noise floor. SNIR is shown as 0 db for some reason in the 5 GHz channel.

Any tips how I should troubleshoot why clients can't associate with the IAP?

This customer had problems with their previous low end AP but those went away for a while by restarting the AP, so it was replaced. This time rebooting didn't help so to my mind looks more like interference or software issue. The IAP is running the latest software version.

Can you start by avoiding DFS channels?  Anytime you have radar, there will be disruptions, but it should recover.

Yes, I modified valid channels to include only UNII-1 below 50. We'll see how it changes things. There is another SSID that the client tried which also includes 2.4 GHz band, but I guess it's possible that the clients tried to connect to 5 GHz even if there were radar interference.

I read that radar avoidance can cause the whole IAP to reboot, but I'm not sure if that's still the case with current firmware, or will it just hop to another channel? Should radar interference be visible in other areas except just in log messages?

What about the fact that noise floor was -92 but SNIR was 0 db? Would that be indicative of some specific interference, or would it display that if there isn't enough data to calculate the value? There was only one dormant client connected at that time.

I am not sure what to think about your issue. The 305 is not yet approved for DFS channels so while it can detect radar on  DFS channels, it iis not allowed to serve clients on those channels.  Also it is false that an  Aruba AP reboots when it sees radar.  If you can point out the documentation to us, we will get it corrected.  A -92 noise floor is fine.  A displayed SNR of zero on a client is inconclusive.

I don't remember where I read that reboot information, I might have been mistaken. I vaguely remember something in the logs about "radar detected...rebooting" but I'm not sure and can't find it anymore.

Hmm...You said that 305 is not yet approved for DFS channels and shouldn't serve clients. Here's ARM history from the IAP:

show ap arm history

Interface :wifi0
ARM History
-----------
Time of Change       Old Channel  New Channel  Old Power  New Power  Reason  Result
--------------       -----------  -----------  ---------  ---------  ------  ------
2017-06-01 15:50:28  116E         52E          21         21         R       Configured
2017-06-01 15:49:50  116E         116E         Max        21         P-      Configured

Aren't those both DFS channels in europe? I have background spectrum monitoring enabled.

I apologize.  The DFS channels are not approved in the US regulatory domain.  I would exclude DFS channels in your regulatory domain to avoid issues in area where there could be radar.

If there is a connection issue, you should open a TAC case in parallel, because they would have access to your entire tech support instead of us guessing what your issue could be on this forum.  We can give you some ideas, but it could take quite awhile..

You also have your access points at max power, which can cause a whole range of issues.  I would start with the minimum of 12 and maximum power of 18.

I wrote an article about how to configure wireless to give it the best chance of working here:  http://community.arubanetworks.com/t5/Technology-Blog/Removing-the-Bottleneck-in-Wireless/ba-p/77978  See if any of it can be used in your situation..

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@cjoseph wrote:

You also have your access points at max power, which can cause a whole range of issues.  I would start with the minimum of 12 and maximum power of 18.

 

I wrote an article about how to configure wireless to give it the best chance of working here:  http://community.arubanetworks.com/t5/Technology-Blog/Removing-the-Bottleneck-in-Wireless/ba-p/77978  See if any of it can be used in your situation..

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Thanks for that. This is a single access point so we would like it to cover as much area as possible, but I'll look into tweaking the power accordingly.

Thanks for your help, I will open a TAC case if it comes back. I've now excluded DFS channels. Today it seems to be working again.

What logs would you suggest I gather if it comes back? Is tech support dump enough or should I get something else? I'll advise the customer NOT to reboot the IAP if there is a problem but contact me first so I can get all the logs while it's running.

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@SpreadSpectrum wrote:

Thanks for your help, I will open a TAC case if it comes back. I've now excluded DFS channels. Today it seems to be working again.

 

What logs would you suggest I gather if it comes back? Is tech support dump enough or should I get something else? I'll advise the customer NOT to reboot the IAP if there is a problem but contact me first so I can get all the logs while it's running.

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The tech support dump should be enough to get to the bottom of it, yes.