C9115AXI Reboot issue

[JeongSeok_Kim]

Hi

4 out of 6 wireless APs connected to a specific switch have an unknown reboot problem.

WLC Model: C9800-L-F-K9

WLC OS: 17.6.3

Uplink Type: 1G UTP

AP Model: C9115AXI

AP OS: 17.6.3

Uplink Speed: 1G UTP

Power: AIR-PWRINJ6

Switch Model: C2960L-24TS

Switch OS: 15.2(6)E

The Max Retransmission or Heartbeat Timeout on the WLC identifies the reason for disconnection, and the reboot reason is Unknown on the wireless AP itself. This phenomenon occurs repeatedly for as short as 20 minutes and as long as 4 hours.

There is no clear cause analysis result in Cisco TAC, and the action method for me to solve it myself is as follows.

1. Downgrade WLC OS 17.6.4 -> 17.6.3 : Unresolved

2. Replacing all 4 problematic wireless APs : Only 1 wireless AP problem is resolved

3. Wireless AP power injector and switch port replacement : Unresolved

4. Syslog setting in wireless AP: Wireless AP reboots without sending any specific log to syslog

5. The demolished wireless AP, which had an existing problem, was connected to the computer room for testing purposes : the reboot problem was not reproduced.

Has anyone experienced and resolved these symptoms?

[Rich R]

No, not seen any particular problem like that with 17.6.4 - pretty stable for us.

It could be particular types of traffic which trigger the AP crash.  That traffic might be present in your remote location but not in your computer room.  Also were you using the same power supply in the computer room (unstable power supply can also trigger reload)?

I certainly would not recommend downgrade to 17.6.3 - don't know why TAC told you to do that.  Upgrade to 17.6.4 solved a number of problems for us.  17.6.5 is out now and includes a number of AP crash fixes so try that?
https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-6/release-notes/rn-17-6-9800.html#resolved-caveats-1765

[JeongSeok_Kim]

hi

Downgrading to 17.6.3 was my decision and my final action was to replace the L2 switch.

I didn't find anything unusual in the show tech of the L2 switch, but I couldn't get support because there was no Cisco service, and it was eventually resolved after replacing the L2 switch hardware.

Thank you for posting.

[Flavio Miranda]

Hi

 This can be some kind of incompatibility. If we look at the Power injector data sheet it states:

"The single-port PoE injector provides up to 30 Watts and is compliant with IEEE 802.3af (15.4 W) and
IEEE 802.3at (30 W) systems. This power injector is for use with the Cisco Aironet 2800 series and 3800
series access points."

And looking into Access Point Datasheet it states:

Cisco power injector, AIR-PWRINJ5= (Note: This injector supports only 802.3af)

https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9100ax-access-points/datasheet-c78-741988.html 

[JeongSeok_Kim]

hi

Downgrading to 17.6.3 was my decision and my final action was to replace the L2 switch.

I didn't find anything unusual in the show tech of the L2 switch, but I couldn't get support because there was no Cisco service, and it was eventually resolved after replacing the L2 switch hardware.

Thank you for posting

[Rich R]

Any AP which works with AIR-PWRINJ5 should also work with AIR-PWRINJ6 but the converse does not apply (so APs which require AIR-PWRINJ6 may not work with AIR-PWRINJ5).

[Polestar]

Hi

We are running 17.3.5.42 on C9115AXI and our  upstream switches are all C9000 series. I am experiencing  the APs connected to the upstream  switch reloading without any warning error msgs - anything between 4 mins to 4 hours ...

[JeongSeok_Kim]

Hi Polestar

1. Does the reboot occur unconditionally within 4 hours?
2. Is there a reboot without outputting anything in the console log of the wireless AP?
3. Is the wireless AP power connection supply method PoE? If it is PoE, is the switch power module redundant?
4. If the PoE switch power module is redundant, can you repeat the test by disconnecting and connecting the power cable of the PS-1 power module?
5. Does the wireless AP reboot after doing step 4?

[Polestar]

Hi Kim 

the answers to your questions...

1. Yes - reboots unconditionally

2. No logs -only notification of AP connected ( up-stream switch  ) interface up/down 

At this moment i am on my way to site to obtain the AP console logs as i cannot obtain them remotely. As the reboot  occurring at random times , its a "wait game" 

[JeongSeok_Kim]

Hi, the reason I asked for the reason is that the irregular symptoms disappear when the wireless AP hanging from the bracket on the ceiling is removed. We narrowed down the cause to a leakage current issue and proceeded with insulation work.Hi, the reason I asked for the reason is that the irregular symptoms disappear when the wireless AP hanging from the bracket on the ceiling is removed. We narrowed down the cause to a leakage current issue and proceeded with insulation work.

[Rich R]

Upgrade to 17.9.3 + APSPs or 17.9.4 (see TAC recommended below) and make sure your C9000 switches are alos running up to date code.

[TAESU Kim]

지금도 무작위로 재부팅 되는 증상이 있으신가여?

저도 같은 증상을 격고 있어서 문의 드립니다.

WLC - C9800-L-F-K9

AP - C9115AXI-K

Poe - C9300L-24P-4G
특이점은 천정에 매달았을경우 발생합니다
책상위에 올려놓고 테스트를 하면 문제가 없습니다

별도의 파워 인젝터를 사용해도 문제가 없습니다

Poe 스위치를 C3560G-24PS 로 교체한 경우 문제가 없습니다.

[Rich R]

@TAESU Kim what version of IOS-XE code is the WLC running?
Have you updated the PHY firmware on the WLC? (see TAC recommended doc below)

What version of IOS-XE code is the C9300 running? (that should also be up to date)

Most crashes (and reloads) are caused by software bugs (less frequently by hardware problems) so the first thing to do is make sure all the software is up to date.

[JeongSeok_Kim]

Hello Taesoo Kim

Does the hanging from the ceiling mean that you have installed the wireless AP on the bracket?

If you fixed the bracket with a piece rather than a rail, you can try to fix it by wrapping insulating tape around the piece.

Did you attach a bracket to the wireless AP when testing by placing it on the desk?

The fact that the symptoms disappear when the switch is replaced with an old model was the first thing I learned about that I had not tested in the environment.

[Polestar]

Hi

Just a quick update on this wierd scenario:

I removed the AP from its ceiling mounting bracket, so it was hanging by the interface cable ( connecting to the upstream  switch ). I connected to the console port - that was yesterday and since then the AP has been UP ( no reloads no issues ) for iver 21 hours now. 
What I have done now is I have remounted the AP to the ceiling bracket  and waiting and watching the console msgs ( which seems to show no msgs at all  )... Lets see if it crashes/reloads  now