Subject: [Isis-wg] circuit type in isis ...

From: NetProtocols Engineer <[email-masked]>
Date: Tue, 18 Sep 2001 11:56:38 -0700 (PDT)

Hi! Out of curiousity (i.e. I have no real need to do this
right now, but, ...): How do I determine the circuit type
(p2p, broadcast, etc) for an ISIS interface if I am not
directly connected to a router?

So, e.g.:

  R1 ------- { Network } ------- RD
   |
   |
  R2

How can RD determine if R1-R2 link is p2p, nbma, bcast, etc?

Thanks for your responses.

__________________________________________________
Terrorist Attacks on U.S. - How can you help?
Donate cash, emergency relief information
http://dailynews.yahoo.com/fc/US/Emergency_Information/
_______________________________________________
Isis-wg mailing list  -  [email-masked]
http://external.juniper.net/mailman/listinfo/isis-wg

---

From: Tayfun Gol <[email-masked]>
Date: Tue, 18 Sep 2001 15:46:28 -0400

> Thanks for your responses.

First of all, there is no notion of nbma networks in IS-IS ( at least
not in the current standards ), you either have PTP or broadcast links
in the topology as far as IS-IS is concerned.
For the topology above, the type of the link between R1 and R2 can be
determined  from  IS reachability TLV's advertised by R1 or R2. If the
link between R1 and R2 were a multiaccess link, R1 and R2 would be
advertising reachability to the elected DIS on that network and whoever
became DIS would generate a pseudonode LSP advertising reachability to
R1 and R2 back. If the link type were PTP, R1 and R2 would be
advertising reachability to each other directly.

Hope this helps..

Thanks,
Tayfun Gol
Laurel Networks