[31673] in North American Network Operators' Group
Re: ATM Question
daemon@ATHENA.MIT.EDU (Thomas P. Brisco)
Fri Oct 6 09:09:34 2000
Date: Fri, 6 Oct 2000 09:07:41 -0400 (EDT)
From: "Thomas P. Brisco" <brisco@globix.net>
To: Richard Inhand <chapinhand@yahoo.com>
Cc: nanog@merit.edu
In-Reply-To: <20001006115010.50889.qmail@web10104.mail.yahoo.com>
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Errors-To: owner-nanog-outgoing@merit.edu
We were seeing something similar yesterday (and yup -
it's still there today). We also noted that if you turn on the
record-route options, then your problem will disappear (I suspect
packet options may cause delivery to be ok - though while the RR
option helps, DF doesnt, but "timestamp" will). We're not seeing
packet loss in any other scenario. I noticed, suspiciously, that
there is always a very "hockey toothed" (every other packet) pattern
in the lossage (load balancing onto a botched circuit?).
Things I've played with:
* size 50% (tried 800, 1200, 2500)
* DF 50%
* RR 100%
* pattern seems to be generally 50%
* timestamp 100%
* TOS 50%
We've opened up a case with cisco ... seems pretty
bizarre, but could it be the ATM switch?
As long as we're not using the source address of
the ATM network - things are fine (e.g. sourcing off of
the loopback, going one hop back, etc).
- Tom
On Fri, 6 Oct 2000, Richard Inhand wrote:
> Date: Fri, 6 Oct 2000 04:50:10 -0700 (PDT)
> From: Richard Inhand <chapinhand@yahoo.com>
> To: nanog@merit.edu
> Subject: ATM Question
>
>
> I'm currently looking into a weird problem at an ATM
> peering point on the West Coast, when I ping from my
> peer router to any of my peers I get some but not
> total packet loss, when I ping from one router back or
> use the loopback interface as source things are fine.
> Whereas, with all my other ATM peering point routers,
> for example at MAE-EAST I can ping my peers cleanly
> from the same router. This isn't (to my knowledge)
> affecting traffic just wondering why this strange
> phenomenon should occur only in the one place.
>
> Any body else had any similar problems?
>
> Richard Hand
>
>
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