Cisco GSR, Gig Ethernet config?

Ron Buchalski rbuchals at
Fri Feb 12 17:01:34 UTC 1999

>Date: Thu, 11 Feb 1999 15:19:55 -0800
>From: John Haskins <jhaskins at>
>To: nanog at
>Subject: Cisco GSR, Gig Ethernet config?
>Our configuration:  a GSR12008 with two interfaces, an OC12 ATM to
>the WAN and a gig ethernet to the campus, serving as a border drain.
>Does someone have real experience configuring this box with SFCs and
>CSCs?  Is a full switch fabric (3 SFCs) and second CSC required or
>desirable for the gig ethernet interface to work?  Could we expect to

Yes, in order to use the GE linecard you need to have the full switch 
fabric installed.  The second CSC is optional.  Without it, the switch 
fabric is non-redundant.  With it, you have 1:4 redundancy, since the 
CSC can back up either the CSC or any SFC.

>support a second gig ethernet interface?  So many questions!

When equipped with the full switch fabric, the 12008 is a 40Gb/s router.  
Each slot has a 5Gb/s connection to the switch matrix.

Given that you are using one OC12 ATM linecard (1.2Gb/s total bandwidth) 
and one GE linecard (2Gb/s total bandwidth), you're not pushing slot 
limits or router limits.  There's plenty of available capacity to 
support a second GE linecard.


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