Subject: [Isis-wg] M-ISIS

From: Chris Sherwin <[email-masked]>
Date: Fri, 26 Oct 2001 13:45:03 -0400

Hi all,

Is this M-ISIS draft similar to/the same as the multi-instance IS-IS
Juniper has?
Does CISCO support something like this?

Chris.

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From: Naiming Shen <[email-masked]>
Date: Sun, 28 Oct 2001 22:10:20 -0800

To the wg list, the new version M-ISIS 01.txt has been posted on ietf
websiet. The main change is to add an IPv6 reachable prefix TLV for
multi-topology(section 8.4). Please send comments.

 ]Hi all,
 ]
 ]Is this M-ISIS draft similar to/the same as the multi-instance IS-IS
 ]Juniper has?

    No. The main point of M-ISIS is "SINGLE instance".

    Even though its possible to use multi-instance to form multi-topology
of ISIS, the tricky thing is if more than one instance need to share the
same interface on a router, a mechanism is needed to multiplex inbound
isis packets to the right instance. Although one can freely add new TLVs
inside ISIS packets, the issue is backwards compatibility, especially when
the DIS on a LAN runs old code.

    But M-ISIS does not exclude multi-instance application of ISIS.
It will be perfectly reasonable to run multiple instances of M-ISIS on
a router. If two networks both run M-ISIS as IGPs resides on the router,
multi-instance of M-ISIS will be useful there.

 ]Does CISCO support something like this?
 ]
 ]Chris.

- Naiming