ping times between access and core question

[mattM26]

Hello All,

Just have a question in regards to ping times between access layer switches and the core, so in my org we have about 8 IDFs with 2x 10G links port-channeled up to the core. 1 of our IDFs has very weird ping times (showed a max time of 97ms) when pinging between core and the access switch vs every other closet is showing 1ms.

what could be the cause of this or what's best way to troubleshoot? the only difference on this switch is we have about 19 security cameras on this stacked switch but could that be causing the issue? Also, even when i SSH to the switch i do notice some delay when typing commands, not super bad but still noticeable. I do have PRTG setup and the uplinks to the core aren't even being hit that bad, less than 20Mbs and cpu/memory totally fine.

If more info is needed please let me know

Thank you!

[Reza Sharifi]

Hi,

So, a couple of items to check. One would be to compare the config between this IDF and another IDF that does not have this issue. Sometimes, enabling a feature on IOS can bug down the switch and cause latency. The other thing to check for is high CPU by issuing this command:

"sh process cpu sort | ex 0.00"

and compare it to another IDF. 

HTH

[mattM26]

oh that command is awesome, so i saw the pings go up and i ran that process command and I see "SAUtilReport" go up to 98% for past 5 sec and after a few the past minute shows 68%.

This may be the culprit! i'll look up to see what this is and open a TAC case if necessary.

I am not seeing this SAUtilReport on any of my other switches.

[Reza Sharifi]

That is it!

This may also be a bug. So, you may have a downgrade or upgrade based on TAC's findings.

HTH

[mattM26]

yeah could be, the weird thing i got about 10 other 9300 switches runnign the same code and all of them are fine, will check the configs too as you mentioned maybe something is off.

Thank you!

[MHM Cisco World]

Do traceroute see how many hop between two sw

[balaji.bandi]

1 of our IDFs has very weird ping times (showed a max time of 97ms) when pinging between core and the access switch vs every other closet is showing 1ms.

is the config the same for all the devices, same uplink speed? what distance compare to other IDF ?

what is the utilization of the Link at that time when your pinging takes place. ?

is the ping from the end device or switch to the core?

[Joseph W. Doherty]

BTW, also keep in mind, Cisco routers and switches generally give low priority to processing ping replies.  I.e. it's not unusual to "see" erratic ping times when pinging a Cisco device, especially if its control plane is busy doing something else.

For "better" ping latency testing, you should ping through the Cisco device, not the device itself.