[j-nsp] How to trace fpc/cfeb CPU usage?

[Joerg Staedele / Trusted Network GmbH]

On Sat, Feb 17, 2007 at 12:10:11AM +0100, Rafa? Szarecki wrote:
> Hi all,
> 
> FEB/CFEB CPU is responsible for delivery information between PFE (asics) and
> RE.
> 
> If your m7i is doing packet sampling (netflow/jflow, or to file)? This is
> one of very often reasons of hi CPU usage.
> 
> This CPU is also responsible for generate ICMP reports like e.g. "TTL
> exceeded" or "No route to host". This can be another reason - too many
> packets.
> 
> This CPU is also responsible to handle options in IPv4, e.g. if source
> routing  is set. The best prectice is to disable forwarding of such packets.
> You not need this for any resonable application - this is used by black hat
> guys.
> 
> Is this Hi CPU load periodical? If this period is inline with some statistic
> gathering (from outside via SNMP, or internaly to file. e.g. LDP stats
> period)
> 

Hi,

on the M7i we do not have Sampling running. Also there are no link-flaps, bgp flaps etc.

The router is just doing 400-600Mbit/s with about 80-120kpps.

Is it possible to turn off the "ip unreachables" (cisco-speak)? The M7i is in front of a lot of subnets so this unreachables *might* cause it when 
someone is doing scans on several subnets.

source-route is already disabled.

I dont have a graphical view of the cfeb cpu usage yet (is it possible via snmp?)

Regards,
 Joerg