CSS : ISC problem

Unanswered Question
Feb 12th, 2008


I noticed in CSS11500 documentation Cisco advice not using level 2 devices for Inter-Switch Communication (see at link at the end). After sniffing, it appears ISC works with broadcasted ethernet frames.

So how should we proceed to link two redundant content switch distant from several kilometers ?

My problem is, in spite of cisco recommandations, I've linked CSS through two C65xx. Link works but become down for a very short time periodically (each 10 minutes).

This seems to have no incidence on reliability...


Thank you,


I have this problem too.
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Gilles Dufour Tue, 02/12/2008 - 09:07

the protocol was design for short distance and L2 connection.

This is why we recommend to not use switches to interconnect CSS ISC link.

It may work with switches but there is no guarantee.


David Coupez Wed, 02/13/2008 - 00:36

Ok thus how Cisco recommand to handle separated CSS distant from several kilometers?


Gilles Dufour Wed, 02/13/2008 - 04:17


there is no recommendation as the protocol was not created for long distance (meaning several kilometers).


David Coupez Wed, 02/13/2008 - 05:00

Oh... so a cisco backup CSS can never be a real backup if CSS have to be in the same room to work... What's happend in case of fire ?

My company owns 11 CSS and they are too critical to regroup them. So I think cisco should investigate this problem as soon as possible!


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