IS-IS and BGP as CE-PE

Unanswered Question
Sep 30th, 2008


Does any one know or has a document that explains why IS-IS is not supported as a protocol to use on CE routers?

Also, more specifically, IS-IS is not supported, because you can not run it per VRF?

I am just trying to understand why we can't use IS-IS the same way we use OSPF.



I have this problem too.
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Harold Ritter Tue, 09/30/2008 - 05:29


ISIS is actually VRF aware.

What is missing is the standardization to use it as a CE-PE protocol. If you look at OSPF for instance, it required an RFC explaining how OSPF attributes could be propagated from one PE to the other using BGP extended communities (see RFC4577). This has not happen yet for ISIS and i haven't heard of anything coming soon in the IETF.


Reza Sharifi Tue, 09/30/2008 - 07:38


Thanks for the link and explanation.

I will take a look at RFC4577.



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