Increased CPU on Router after Bandwidth Upgrade

[randyclark]

We just upgraded our Internet bandwidth on our Cisco 2650XM from 12Mps to 21Mps. The router is running BGP and partial routes. The CPU is running 30-35% where as before it ran in the low 20s. How high can the CPU run and still be considered acceptable? Will a memory upgrade help?

[mheusinger · Accepted solution]

Hi,

average CPU values up to 40% are usually acceptable. At least that is, what you might get with many (customer) BGP routers depending on the scenario.

The only thing to consider is: are there any features, which could request this extra CPU? (like OSPF is flapping, additional VPN traffic and the like). The CPU should be capable of also coping with out of the norm situations.

Regards, Martin

[vijayasankar]

Hi Randy,

30-35% should be ok for this platform.

Generally it is hard to say any acceptable upper limit.

It is better to have a baseline utilisation monitored in your network, to closely watch any spikes.

Any such spikes should be closely diagnosed to find out the reason.

To investigate more, we need to find which particular process is consuming the CPU resource, to assess whether it is in acceptable range for your setup.

You can have a look at this URL to start your investigation.

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a70f2.shtml#prereq

With out diagnosing which process is contriubuting for the cpu hike and arriving at the root cause, Memory upgrade will not help in this case.

-VJ