[nsp] ATM problems (DSL)

[Charles Sprickman]

On Sat, 5 Apr 2003, Gert Doering wrote:

> Hi,
>
> On Sat, Apr 05, 2003 at 12:14:26PM +0100, Chris Roberts wrote:
> > Using cricket or another tool to examine your CPU usage isn't very useful,
> > try 'sh proc cpu' (and run it regularly, say, every 10 seconds). CPU usage
> > can burst for a second or two when a routing update is received and then
> > drop back to normal, and these kind of spikes would easily get averaged out
> > with cricket unless you're sampling every second. It's these CPU spikes that
> > can cause the packet loss (or are a symptom of it).
>
> Very recent IOSes have "show proc cpu history" which prints nice
> graphs of the CPU peaks over the last 60 seconds / 60 minutes / 72 hours.

I do have that available, and the 60 second graph stays below 60%.

To update the issue, I have "fixed" some of these problem customers by
moving them from the BVI to RBE using an unnumbered loopback interface.

This really just leaves me even more stumped about what the actual problem
is.  If it was an issue with the router or the router config, I do not at
all understand why this is just 9 customers out of 200-some bridged
customers.  We've started graphing a large number of "random" bridged adsl
customers on the BVI, and are not seeing the problem there.  And before
moving the problem customers to RBE, we had changed their IP, changed the
pvc, and had the covad NOC manually re-route them within their ATM
network.

Any ideas why moving to RBE "fixed" these people?  I'm at a loss.

I am suspicious of the drops I see on the BVI, but I'm not sure what a
drop there indicates.  Is it a drop at the atm interface?  A crc error?
Buffers (if there are any) assigned to the BVI?

The major question I have is "why only a small group of customers?".

CEF problems?

Thanks,

Charles

> gert
>
> --
> USENET is *not* the non-clickable part of WWW!
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> Gert Doering - Munich, Germany                             gert at greenie.muc.de
> fax: +49-89-35655025                        gert.doering at physik.tu-muenchen.de
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