[c-nsp] 2651xm performance experience

[Rodney Dunn]

Post the 'sh proc cpu'.

It sounds to me like it's a background process running or are you saying
you know this specific traffic flow through the box happens every
90 seconds?

On Fri, Sep 29, 2006 at 10:58:06AM -0400, barney gumbo wrote:
> I have a pair of 2651xm which are running high CPU at ~10 min intervals. The
> CPU runs up to about 90% for ~90 seconds then recovers.  The bandwidth being
> consumed when this happens is less then 700 kbps total through the router.
> I believe the 2651xm is rated at 20 mbps, when there are no fancy
> configurations/features etc.  Both routers are currently running 12.4 latest
> releast, base IP image.
> 
> I know the traffic flow which occurs when the CPU runs up, and that flow is
> normal expected traffic, as noted only consuming ~700 kbps.  The 2651xm have
> performed well for me in the past as a simple LAN router, routing between
> two fast-e networks, and we definitely got alot more then 700kbps, typically
> around 15 Mbps, w/o any issues.
> 
> Each 2651xm is configured with 4 pt-pt T1 links and a single fast-e link to
> a LAN.  The routing protocol is EIGRP.  There is a QOS policy which matches
> some VOIP traffic and assigns it to a priority queue which reserves 50% of
> the interface bandwidth, everythig else is fair-queue.  There are no special
> features enabled on the router, no NAT, no interface access-groups, no
> policy-routing, very simple configuration.
> 
> I've tried using MLPP for the 4x T1 and I've also tried this with each T1
> being in it's own /30.  In both scenarios, traffic is being balanced well
> across the T1's in both directions.  High CPU happens with MLPP or each T1
> having it's own /30.  Each T1 is performing fairly well, other then slightly
> high latency (no jitter however) they take the same physical transport path.
> 
> As best as I can tell, the router isn't doing any IP fragmentation or
> generating/processing alot of ICMP traffic.  IP Cef is enabled.
> 
> I've tried downgrading to 12.3 latest release, same CPU consumption.
> 
> Can anyone provide any insight to why this might be happening?
> Any suggestions on how to troubleshoot this further?
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