SG550XG Stacks - CPU Utilization ~ 94% with VRRP and RSTP configuration

[Klaus Ohlmann]

Hello everyone,

first of all I want to describe our network topology:

We got two SG550XG switches. One fibre switch which connects to our access layer switches (also cisco) and one copper switch. They're both stacked.

Attached you could find cutouts of the configurations (core1 and core2).

The cpu utilization of the root bridge is still over 90% in daily business. The other one settles at 40% - 50% cpu utilization.

During the day with high load on the cpu we have more packet loss, higher respones times and ping aborts.

We tried to find out which process caused the high load of the cpu but there isn't a command on this switch to show the single processes.

Therefore we changed the priority in the bridge settings to change the root bridge. The result was the same high cpu load ( ~ 94%) on the other switch.

Does anybody have an idea how we could fix this issue or reduce the cpu load on the root bridge?

Thank you for your help.

KLAUS, Systems Administrator, IT-teacher and Cisco Network Associate.

[Deepak Kumar]

Hi,

Share the out of below commands:

show mac address-table count

show cpu input rate

show cpu utilization

show arp (parse the output, I'm only interested in # of entries)

show services tcp-udp

show log file

I found that you have enabled IGMP and DHCP Snooping, try with disable both and SNMP also.

and finally, try to upgrade the latest firmware.

https://software.cisco.com/download/home/286305659/type/282463181/release/2.4.5.71

Regards,

Deepak Kumar

[Klaus Ohlmann]

Hi,

Thank you for your reply.

Attached you could find the output of the commands.

I will try to disable IGMP and DHCP Snooping within the next days and post the results.

Kind regards,

KLAUS, Systems Administrator, IT-teacher and Cisco Network Associate.

[Deepak Kumar]

Hi,

I am looking that Core-2 is showing high CPU utilization with few logs:

12-Mar-2019 10:17:39 :%HTTP_HTTPS-E-DIAGNOSTICS: in <RL_vtQueryEntryGet> tag, the key rlDnsClDomainNameName is missing in the query.

31-May-2018 04:49:42 :%Stack-E-VERSION-UPDATE-FAILED: Unit 2 - failed to update image

What are current time on the switch and check Unit-2 for any version mismatch? 

Regards,

Deepak Kumar