TX Retries and Spectrum Analysis

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  • Updated 4 years ago
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I am getting a lot of TX Retry Rate alarms on nearly all my APs on both frequencies (and have been for some time). I fiddled with my radio profiles, turned the power down a bit on both radios which has seemed to help a bit.

Anyway...I was attempting to use the spectrum analyzer to get an insight into what's going on but when I use it on AP120's, I receive no data. I swear prior to v6.1 I was able to.

It DOES show data when I run it on my AP330's.

Is this expected behavior, or is something screwy going on?

Also, any advice on where to start with TX Retry rates?

Thanks as always!
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Benjamin Lambert

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Posted 5 years ago

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Nick Lowe, Official Rep

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The HiveAP 330s use the AR9390 which does have such support:

http://www.qca.qualcomm.com/technology/technology.php?nav1=47&product=90

The HiveAP 120s use an older generation Atheros chip which may not support it, but I'm not sure which one so cannot research the details...
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Benjamin Lambert

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I haven't used the tool in a while so my memory is rusty. I could swear I used to use it on the AP120's as that's what the majority of my installation is.

Then again, I could be horribly wrong. It happens sometimes (well...twice anyway).
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Brian Powers, Champ

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I believe the only AP group that wasnt capable of the spectrum analysis was the 320/340 series. You will not get the option to view it under Utilities if the AP doesnt support it.



vs.



I cant get any of the 120s I have access to to show any spectrum analysis data either. Running code 6.0r2.
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Nick Lowe, Official Rep

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Looks like it should support it:

"Like Aruba and Meraki they are able to get the same resolution bandwidth from the Atheros chipset of 357kHz. In their current implementation this works with the Atheros 9200 chipset model APs (the Aerohive 110/120), have a variable sweep time down to 1 second and come with signatures for microwaves, bluetooth, DECT phones, baby monitors and video cameras."

See: http://www.wifikiwi.com/wireless/aerohive-hiveos-hivemanager-4-0/
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Andrew MacTaggart, Champ

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I would add some of this info

http://community.aerohive.com/aerohiv...

I am trying to figure out if TX frames dropped by SW are related to RF or not vs frames dropped by radio.

according to the docuementation Frames dropped by SW can be
Invalid format
Client is no longer answering
or buffer problems

"The frames might be improperly formatted, the total number of frames might exceed the data buffer, or they cannot be delivered—perhaps because the station has roamed to another HiveAP. "

SA will give you some insight to Layer 1 issues, but I think you are going to have to look at Layer 2 as well.
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Benjamin Lambert

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I figured I would update this thread with some more information.

I started directing my AP's debug level syslogs to a Splunk server for aggregation and searching. i attached a screenshot that nicely shows the number of tx retry events over the course of time.

At the suggestion of Aerohive support, I fiddled with my radio profile settings a bit, removing some of the high density settings and adjusting the radio power down a bit. You can see at the beginning of the graph the insane number of errors. That afternoon I pushed out the new radio profile. As you can see, the following week had far fewer, but still quite a few alerts.

Then last Friday, I finally removed my 'legacy' SSIDs, so now I'm only broadcasting 2 SSID's on 2.4ghz, and 1 on 5.8ghz. This seems to have further reduced the number of TX errors.
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Crowdie, Champ

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Which of the high density settings did you remove?
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Amanda

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Thanks for the update Benjamin.
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Benjamin Lambert

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Specifically I changed the SLA from High Density to Normal, set it to deny B clients, and unchecked the Enable High Density settings.

See screenshot
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Crowdie, Champ

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To add to Benjamin's experience we had a high density data only deployment where the high density WLAN and SLA settings had been enabled and everything worked OK.  However, when some legacy devices associated to the wireless network they could experience poor performance and in the packet captures we could see some access points rejecting the legacy device's reassociation requests.  By disabling the high density settings this issue was resolved and the reassociation requests were accepted.
(Edited)