[j-nsp] GigE: M10 <-> Cisco Catalyst 6509: oversized and corrupted frames

Dmitri Kalintsev dek at hades.uz
Sun Mar 30 19:17:17 EST 2003

Hi Matti,

I may sound stupid, but have you tried to replace the fibre cable between
your Juniper and Cat to the ONE THAT IS KNOW TO BE GOOD? We had a problem at
one point when the cable appeared to be good but was starting to give errors
if bumped or disturbed by an aircon airflow.

May I also suggest obtaining an optical splitter for your GigE link so that
you do actually capture what is going on on the glass, rather than trust the
Cat to copy stuff for you (which as I understand was already proved useless,
as it wouldn't forward broken frames, and I do understand the reasons behind

There's also one more quetion: is your Cat running in native mode or hybrid?
If it is hybrid, then where do you see the errors about corrupt IP headers
(I would imagine it being MSFC, but if it's on Sup side, then it could be
something to do with the way MLS switching is done) (?).

How periodical are your errors and do they concide (J and C side)?

More questions than answers but... ;)


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