[c-nsp] Best practice - Core vs Access Router

Saku Ytti saku at ytti.fi
Tue Feb 9 08:04:21 EST 2010

On (2010-02-09 13:56 +0100), Andy B. wrote:
> I think I am not software switching:
> CPU utilization for five seconds: 19%/5%; one minute: 46%; five minutes: 42%

Could you try to catch this when the five second value is >40% so we'll see
what is causing the load. Currently what ever is happening, is not
Output 5s sorted list.

>                      Module       pps   peak-pps                     peak-time
>                      5        4443376   10849623  12:44:28 CEST Mon Dec 21 2009

10Mpps peak, well within limits of CFC system, so you're not anywhere near
the performance limits.

> Netflow Resources
>           TCAM utilization:       Module       Created      Failed       %Used
>                                   5             262020           0        100%

Netflow full, highly typical and nothing to worry about.

> I do see input drops - what does that mean?

It means that you got more packets towards software than buffers could
hold, default is 75 packets, which is way too little for even some normal
situations, such as BGP, especially route reflector use.
If it is normal, you should increase it to 1k or 2k.

But it might also indicate that transit traffic is coming to control-plane,
there are many tools 7600 offers to troubleshoot them.  When you look at
those interfaces where you see drops, do any of them display packets in
input buffer /right now/, if so, you can use 'show buffers input-interface
X header' to see those packets are, which will go long way to determine if
they are normal or something to worry about.


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