ARP Snoop high cpu

[Ton V Engelen]

Hi

since some days we observe high cpu for the "ARP Snoop" process. 

This is on 6513-E coreswitches running VSS. 

I can not find information about tshooting this process. 

If anyone has a clue, thanks in advance! 

[balaji.bandi]

Can you provide the environment information :

1. what kind of supervisior - show modules

2. what is the current IOS running - show version

3. what was the major change before you noticed this issue.

4. can you provide -

show process status

show process 

Show process CPU sorted | ex 0.0

Show process cpu history

here is arp related issue community post :

https://community.cisco.com/t5/switching/6509e-vss-high-cpu-process-due-to-arp-input/td-p/1819465

here is troubleshooting guide if you are not visited already

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/63992-6k-high-cpu.html

https://supportforums.cisco.com/document/59926/troubleshooting-high-cpu-6500-sup720

https://community.cisco.com/t5/networking-documents/troubleshooting-high-cpu-on-a-6500-with-sup720/ta-p/3126932

https://community.cisco.com/t5/networking-documents/troubleshooting-with-a-netdr-capture-on-a-sup720-6500/ta-p/3127361

[Ton V Engelen]

Hi thanks!

i already figured it out and solved the issue. 

[balaji.bandi]

If the issue is resolved can you post the solution and mark as this post as solved, so it will be usefull for other community members who has same issue.

[Joe2934]

Could you please share the solution? how did you fix the ARP snooping high CPU usage

[Ton V Engelen]

It turned out that an old 3750X stack was acting strange and whatever i tried, all traffic from the stack was punted to the 6513 cpu

- so i shut down all access ports on the stack > still same behaviour, high cpu on the core

- then i shut down a member of the port channel uplink,  so the stack only had one link to the core and all access ports also were still shut > same behaviour, high cpu 

I then upgraded the stack to c3750e-universalk9-mz.152-4.E8.bin and the issue went away.