[c-nsp] Cat 4500 series High CPU

[Tóth András]

Hi Terry,

Did you have a chance to review the following documentations?

High CPU Utilization on Cisco IOS Software-Based Catalyst 4500 Switches
http://www.cisco.com/en/US/products/hw/switches/ps663/products_tech_note09186a00804cef15.shtml

Troubleshooting High CPU on the Catalyst 4500-E Series Switch
http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/troubleshooting/cpu_util.html

Mgmt LoPri process is not only responsible for MAC learning, it could
be a couple more things. If you have narrowed down the issue to be
frequent MAC learning, try looking for L2 loops where MAC addresses
might flap between 2 ports and check which addresses are continuously
learnt. Additionally, look for frequent STP TCNs with 'sh span detail'
command and look for topology changes which can cause MAC table
flushing.

If you still need help, I would recommend opening a TAC case.

Best regards,
Andras


On Wed, Aug 31, 2011 at 11:53 PM, Terry Rupeni <rupeni_t at usp.ac.fj> wrote:
> Hi All,
>
>
>
> We have a Cat4506 facing high CPU. Investigating further we have narrowed it
> down to the following on the Cisco Bug Report:
>
>
>
> High CPU due to Mgmt LoPri process, MAC addresses being added/deleted
> Symptom:
> A Catalyst 4500 switch might experience high CPU utilization due to the
> Cat4k Mgmt LoPri process and the K2CpuMan and K2L2 Address Table reviews
> (show platform health. High CPU utilization does not impact the traffic
> switched in hardware.
>
>
>
> Conditions:
> The problem is seen when a large MAC address table exists and when the
> switch is frequently relearning MAC addresses on multiple VLANs. Enabling
> service internal followed by debug platform log feature k2l2addresstable
> will show output similar to the following. Do not enable these commands on a
> production switch unless instructed by Cisco TAC.
>
>
>
> However no solution is recommended by Cisco. As this is a production switch
> don't really want to do a debug right now.
>
>
>
> Has anyone faced a similar issue?
>
>
>
> Thks
>
> Terry
>
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