Cat3550-12G High CPU Utilization

[allen.hu]

Just deployed a Cat3550-12G IOS version 12.1(22)EA4 and experienced unusually high CPU utilization (69%), triggered by a process called VegasPM (63%). The switch is operating L2/3 with a few simple ACLs. Any idea about this problem?

[szahid]

Allen -

Could you please upload the config of the switch. How many L3 interface are you using ? Also please provide the o/p of "show sdm prefer"

thanks

Salman Z.

[allen.hu]

Hi Salman,

The config file is attached below. Here is the o/p of "sh sdm prefer":

SW3550-CORE#sh sdm prefer

The current template is the default template.

The selected template optimizes the resources in

the switch to support this level of features for

16 routed interfaces and 1K VLANs.

number of unicast mac addresses: 6K

number of igmp groups: 6K

number of qos aces: 2K

number of security aces: 2K

number of unicast routes: 12K

number of multicast routes: 6K

Thanks,

Allen

[szahid]

the only thing that is obvious enough is you have acls with deny statements and if there is a high rate traffic coming in and hitting those entries , cpu will be busy sending ip unreachables back to the sources. Lets try using "no ip unreachables" under the vlan interfaces that have these acls applied on them and see if the cpu goes down.

thanks

Salman Z.

[allen.hu]

Hello Salman,

Thanks for taking time review the config. Just added "no ip unreachables" and it looks like the CPU utilization stay the same. Could this be a bug ?

Allen