Wireless AP's - High CPU

Thomas Yarger · ‎02-27-2014

Experts,

I work at an airport and we offer free wireless. We have about 20 AP's that are configured for the free wireless. Recently, I've been receiving alerts via Solarwinds that all 20 AP's have high CPU (> 80%). I performed a Wireshark on one of the affected AP's and everything looks quite normal. I looked at the Switchport statistics for the same AP and all looks fine. Any idea's on where I should focus my attention?

Jay Ocampo · ‎02-27-2014

Hi,

Do you have loopback interfaces configured on the APs? Could be caused by some kind of storm...

Please review this post from support forums.. Might be related to your issue.

https://supportforums.cisco.com/thread/2269876?tstart=0

Best....

Thomas Yarger · ‎02-27-2014

Jose,

No loopback interfaces.

Jay Ocampo · ‎02-27-2014

HI Thomas,

I see.

Here are some points to check:

1. identify which process is taking high % cpu , show proc cpu | ex 0.00

2. Is the AP residing on a non-vlan 1 network ?

3. Check the switch % CPU too and identify which process is taking the highest % CPU.

4. Observe the broadcast counter on an interface connected to an AP., show interface Gix/y | in broadcast

HTH.

Thomas Yarger · ‎02-27-2014

Jose,

Thank-you for the tips. Regarding point 4, what would be an abnormal amount of broadcast for normal AP traffic? Have a great day!

Thomas Yarger · ‎02-27-2014

CPU utilization for five seconds: 95%/94%; one minute: 78%; five minutes: 76%

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

10 4021906 9180386 438 0.23% 0.13% 0.12% 0 ARP Input

16 2944776 20673592 142 0.15% 0.25% 0.24% 0 Net Background

23 3171526 35394775 89 0.15% 0.04% 0.05% 0 Dot11 driver

62 6357277 18376242 345 0.07% 0.17% 0.22% 0 HyBridge Input P

Leo Laohoo · ‎02-27-2014

Is this autonomous or controller-based AP?

If autonomous, can you post the output to the command "sh version"?

Thomas Yarger · ‎02-28-2014

They're all autonomous. We do have a mixuture of different model AP's. This sh version is one of the problem AP's.

Cisco IOS Software, C1200 Software (C1200-K9W7-M), Version 12.3(7)JA2, RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Compiled Fri 18-Nov-05 12:43 by ssearch

ROM: Bootstrap program is C1200 boot loader

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System returned to ROM by power-on

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cisco AIR-AP1231G-A-K9 (PowerPC405GP) processor (revision A0) with 14838K/1536K bytes of memory.

Processor board ID FOC09420K0R

PowerPC405GP CPU at 196Mhz, revision number 0x0145

Last reset from power-on

1 FastEthernet interface

1 802.11 Radio(s)

32K bytes of flash-simulated non-volatile configuration memory.

Base ethernet MAC Address: 00:15:F9:22:05:BD

Part Number : 73-8704-10

PCA Assembly Number : 800-23211-11

PCA Revision Number : A0

PCB Serial Number : FOC09420K0R

Top Assembly Part Number : 800-23304-11

Top Assembly Serial Number : FTX1006J01R

Top Revision Number : A0

Product/Model Number : AIR-AP1231G-A-K9

Configuration register is 0xF