[nsp] ATM problems (DSL)

[Charles Sprickman]

On Fri, 4 Apr 2003, Chris Roberts wrote:

> > On Fri, 4 Apr 2003, Temkin, David wrote:
> >
> > > What's the CPU like on the router?
> >
> > Looking at cricket, about 40% peak time and down to about 20% overnight
> > and weekends.  Packet loss remains about the same.
>
> What routing protocols is this router running (if any?). Look for CPU spikes
> on the router with 'sh proc cpu' run a good few times over a five minute
> period.

BGP and OSPF.  Two BGP peers, total of maybe 20Mb/s.  I've got cricket
looking at cpu and it's not really spiking.  Both of our upstreams are
stable, with no bgp resets.  Our ospf area encompasses only 3 routers, and
doesn't really change.

> This doesn't explain why it may only affect some customers. I'm guessing
> that only certain customers have complained (e.g. those trying to run gaming
> or time/packet loss sensitive applications).

We have about 9 people that have complained.  We have another random
sampling of about 20 customers in smokeping that we watch and it's like
night and day...

Thanks for all the help folks.

Charles

> >
> > > If I were you I'd up the hold-queue to 150 just for giggles (hold-queue
> 150
> > > on the interface)
> >
> > I'll give it a shot and see what happens...
> >
>
> Increasing the hold queue may alleviate the problem temporarily if it is
> this, however long term I would look at either moving this router into an
> NSSA area if it isn't already or removing BGP from the router if it doesn't
> really need to run it if it is this problem. I've run into a lot of problems
> with routers doing this, and if you're running particularly time sensitive
> applications (game servers, etc being DSL customers) increasing the hold
> queue may not alleviate the perceived problems as you trade loss for (bad)
> jitter.
>
> Also, if it is running OSPF, 'sh ip ospf stat' can be your best friend.
>
> Cheers,
> Chris.
>