High CPU on CAT4006

[spencedavid21]

My Customer has an issue with high CPU running at 70% - 90% with IP input using the majority of the processor.

I have analysed the network and there is nothing obvious as to why the CPU should be so high. The Cat4006 has a SupIII card. The customer has everything set up on Vlan 1 with a Primary and 2 secondary addresses on the interface. Could the Secondary addresses be the reason for this high CPU? I have upgraded the IOS to the latest version.

[sebastian.wiegand]

Hi Spence,

how many devices u have in your Network? (just estimate) more than 100 more than 1000???

Is Routing enabled on your 4006?

why do u need so ip adresses per interface?

Regards,

Sebastian

[spencedavid21]

Hi Sebastian,

The customer has more than 100 devices on the network. Routing is enabled. The 4006 is the default gateway for the devices on the network.

The customer has set up the secondary addresses for testing purposes.

From the trace, the only traffic hitting the default gateway is ICMP traffic from 2 CSS11503.

There is no traffic going to the secondary addresses.

[glen.grant]

I would look around for devices that might be infected , normally packets should be switched but sounds like everything is hitting the processor instead. Clear the counters and look for ports that are incrementing the counters fast and take a closer look at those .

[Prashanth Krishnappa]

What IOS are you running? Can you paste output of sh mod and sh run.

If you are using secondary IP addresses, make sure you have "no ip redirects" configured under the VLAN interfaces to enable hardware switching

http://www.cisco.com/cgi-bin/bugtool/onebug.pl?bugid=CSCdx92162