[c-nsp] OSPF processes

Sergio D. sdanelli at gmail.com
Thu Feb 15 22:24:25 EST 2007


Nothing too nasty on the interfaces. Except for tcp and rtp compression,
would that cause punts to the RP? Also some QoS stuff minor, matching dscp
setting and doing WRR, would that cause punts?

Thanks again,

> Thanks for your response. NPE-400 and yes a VXR chassis.
>
> I second your point on how tricky it can be to determine if its ospf thats
> causing it or if ospf going down is merely a symptom of something else. I
> tend to think is the latter actually since CPU is at 50% during regular
> business hours and it seems to be interrupt driven since there is no
> processes that are high. I just don't think this routers can handle it.
> besides buying a new router, can we just upgrade the NPE?

You could do that.  You may be able to get NPE-G1s on the used market for
a reasonable amount of money, or you could upgrade to the newer NPE-G2.

Before doing that, there may some other troubleshooting that's worthwhile.
I believe another poster mentioned some other bits of diagnosis that would
be good to do.  Also, if you have a CCO account, you can check if there
are bugs in the version of IOS that you're running that could be
contributing to the CPU problems.  It wouldn't be the first time that a
bug has manifested itself in this way.

Are there other features running on the router that could be chewing up
lots of resources?  Full BGP feeds, lots of PPPoX sessions, anything like
that?

Make sure CEF is running on every interface that has any features like
uRPF, Netflow or NBAR applied.

Is there anything else running that could potentially be punting lots of
packets to the process switching path?  Process switching is the most
expensive way to handle a packets, in terms of the amount of work the CPU
has to do.

jms



-- 
Sergio Danellli
JNCIE #170


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