4507 CPU Usage

Unanswered Question

There are a two 4507s at the core of a data centre I am working on. They are running HSRP between them for various vlan interfaces, as well as OSPF as a routing protocol.

I have noticed that the CPU utilisation is sitting at around 37% normally.

CPU utilization for five seconds: 32%/2%; one minute: 37%; five minutes: 39%

The historical CPU shows regular spikes up to 90% and the odd spike to 100%. When I run an extended ping from one of these swithches to a server in the data centre on a different switch, I see spikes up to 100%

Are these CPU utilisations normal for these type of switches? Most of the other core 6500s I've been on are somewhere between 3 and 17%.

One thing I have noticed is that the vlan interfaces of these 4507s are running OSPF between each other on the LAN (ie there is no passive ospf interface config on them). Could the amount of OSPF traffic be burdening the CPU?

Any comments are welcome.

I have this problem too.
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Roberto Salazar Thu, 01/08/2009 - 08:56

yes, at this level I would say it is normal for this platform. The switch does all of it's packet switching at hardware therefore the packet forwarding is not affected by an occasional cpu spike. if the high cpu persists then you need to find which process is causing it to maintain a high cpu util.

Forgot to include the link on troublshooting high cpu on cat4000:


Jon Marshall Thu, 01/08/2009 - 09:02


I agree with Roberto, 35% is not abnormal for these switches especially if they form the core of your network. And 6500 switches in the same position would indeed display a lower CPU utilisation under the same conditions.

Attached is a 4500 CPU troubleshooting doc, may be worth having a look -




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