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New Member

High CPU Utilization short duration

I have a GSR and have high CPU Utilization by short duration due BGP Scanner process. The router has 15 BGP sesion, 4 Full BGP. I´m seeing with show ip bgp summary command some peer constantly deletion and reinsertion prefix received and the version table increase, in adittion say scan interval is 15 secs.

How can i to crrect this situation ?

the above, can affect to some other process on the router? (ie.console, pings)

3 REPLIES
Cisco Employee

Re: High CPU Utilization short duration

This is normal.

BGP scanner will scan the routing table every minute and it will use as much CPU as it can. So, if you have a huge routing table, BGP scanner will most likely need all available CPU.

This process has a low priority, so it will give back CPU if another process needs it.

New Member

Re: High CPU Utilization short duration

OK, I understand that is a normal process, bug What happen with the constant deletion and reinsertion prefix received and the increase version table ?

Cisco Employee

Re: High CPU Utilization short duration

that is also normal :-)

There is a lot of routes in the Internet routing table (> 100k) and unfortunately, not all the routes are stable. So, you will see routes leaving and coming back very frequently (all the time actually).

There is a feature called route dampening to alleviate the problem of instable routes. But, if your not an ISP, I would not suggest to use it.

Regarding the high CPU due to BGP scanner, I forgot to mention this is documented on the web at the following url :

http://www.cisco.com/warp/public/459/highcpu-bgp.html

Gilles.

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