High CPU Utilization Cisco Router 3825

Ahmad Ahmad · ‎10-11-2016

Hi All,

I have cisco routers (3825). They're installed in MPLS Network. Now one of them has CPU High Utilization issue (about 80% - 90%) and the traffic is about 160Mbps. Whether the traffic caused it to happen? Whether the router is still fit for use? Sorry for my english

Anuar Shahrin · ‎10-11-2016

please do show proc cpu sort | ex 0.00 and check the top proc that consume the cpu.

Ahmad Ahmad · ‎10-12-2016

Hi Anuar Shahrin,

Thanks for reply. Please see attached file. Tq

Anuar Shahrin · ‎10-12-2016

From the output we cant see much, maybe because the cpu intermittently high.

Maybe you can try eem script, you may refer

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/116141-trouble-eem-scripts-00.html

or

http://mccltd.net/blog/?p=1803

from there you can capture the proc that causing the high cpu process.

Ahmad Ahmad · ‎10-12-2016

is there another way to collect information about the proc that causing the high cpu prcocess?

Ahmad Ahmad · ‎10-12-2016

I just use snmp-server traps and only got this notification as attached

Joseph W. Doherty · ‎10-12-2016

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Posting

From you posted stats, much of which is interrupt CPU, your high CPU loading might simply be caused by your volume of traffic. As your OP also has the performance rating of a 3845, compare its rating with your traffic volume.

Ahmad Ahmad · ‎10-12-2016

Hi Joseph,

Thanks for reply. i guess you are right. I want to make sure whether it caused the volume of traffic. I've checked the cpu statistics in this morning at low volume of traffic and the cpu run at around 50%. Is there a way to fix it or just upgrade to the new device?

Joseph W. Doherty · ‎10-13-2016

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Probably the best way to "fix" is to use a more powerful/faster router. However, if you carefully review the config, perhaps there might be some configuration changes which might reduce CPU consumption some. (For example, if using ACLs, are the ACEs sequenced in hit frequency, while keeping dependency sequence? Are you using CEF? Have you tried NetFlow caching? Any configuration not needed?)

Ahmad Ahmad · ‎10-13-2016

Hi Joseph,

Thanks for reply. Yes, i'm using CEF. I've never tried Netflow caching. So sad to know that it's not powerfull for my network and the vendor never say anything about it. My routers (3825) in another place look normal for now because they have low volume of traffic. the best way for now perhaps check more deeply my configuration until replace to powerfull router.

Joseph W. Doherty · ‎10-14-2016

Service providers downplay router "sizing" because often usage is less than maximum bandwidth and also because there's often a noticeable price jump between router models.

Conversely hardware vendors will often recommend more than you really need "just-in-case".

Caveat emptor!

SilvioHayashi60030 · ‎11-09-2019

see

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCsm38127/?referring_site=ss&dtid=osscdc000283

@Ahmad Ahmad wrote:
Hi All,

I have cisco routers (3825). They're installed in MPLS Network. Now one of them has CPU High Utilization issue (about 80% - 90%) and the traffic is about 160Mbps. Whether the traffic caused it to happen? Whether the router is still fit for use? Sorry for my english