Wireless and RF

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Occasional Contributor I

fake radar detection

My WIFI network is based on AP60 (AOS 3.3.2.16).
When APs transmit data, some of them (30%) confuse their own signal with a radar and stop to work (for 30mn). In the logs, I can see the radar detection:
<404076> |AP XXX sapd| ^
Sometimes the type id is 22, 34, etc…

-I'm sure that there is no real radar in the environment.
-Radar detection appears just when AP starts to transmit data. We can reproduce the problem systematically, that's why there is no doubt that this "radar" is the AP itself.
-When AP receives traffic, I never see radars.
-AP transmit level is 20dBm, when I reduce the transmitted power (8 dBm for example) the radar detection disappears on a lot of AP (but not all)
- I can't reproduce the problem on my lab, only on the field.

Does somebody have seen this problem before ??
Guru Elite

Open a Case


My WIFI network is based on AP60 (AOS 3.3.2.16).
When APs transmit data, some of them (30%) confuse their own signal with a radar and stop to work (for 30mn). In the logs, I can see the radar detection:
<404076> |AP XXX sapd| ^
Sometimes the type id is 22, 34, etc…

-I'm sure that there is no real radar in the environment.
-Radar detection appears just when AP starts to transmit data. We can reproduce the problem systematically, that's why there is no doubt that this "radar" is the AP itself.
-When AP receives traffic, I never see radars.
-AP transmit level is 20dBm, when I reduce the transmitted power (8 dBm for example) the radar detection disappears on a lot of AP (but not all)
- I can't reproduce the problem on my lab, only on the field.

Does somebody have seen this problem before ??




Please open a case. Radar detection should only be active on the DFS channels and the AP60s should not be running on those channels.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I

same issue

hmm, i have same issue, but i user AP125 and 3.1.7 RN version OS....
Occasional Contributor I

fake radar detection : solution

Finally : problem would come from Atheros Chipset, which is not able to manage correctly DFS2.
This hardware problem appears in special environment not in open area.
I have replaced AP60 by AP124, can't reproduce the problem.
Other solution : use channels without DFS !!
Guru Elite

Dfs

As was mentioned before, the AP60 has NOT been certified for DFS and should not be running on those channels. The 802.11n APs like the AP120 series have been. You should NOT use the AP60 on DFS channels, as this would lead to unpredictable results, like you have seen, especially on code as old as 3.3.2.16, which is from May, 2009.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I

Re: fake radar detection

An unrelated point on fake radar triggers:

We notice that AP105s at boot time induce a fake DFS trigger on neighbouring AP105s. This is with 3200 controllers running 3.4.2.0. Not all neighbouring devices are effected for some reason. We have not conducted further investigation as the issue does not effect production.

A
Guru Elite

Re: fake radar detection

When you say trigger, what happens? What is the message?


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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