[rbridge] IS-IS Level and TRILL Question
Radia.Perlman at sun.com
Sat Jul 25 21:10:02 PDT 2009
I like David's suggested wording. It is a clarification.
As for whether we'd ever want mulilevel TRILL...I'm not sure how
valuable multilevel TRILL
would be since I think the nicknames have to be globally unique within
the entire TRILL campus and there's
no ability to aggregate endnode learning. So it's possible that a campus
would run out of nicknames, or
get overrun with unknown destination flooding or ARPs, long before there
would be any benefit of
moving to multiple levels of hierarchy.
David Michael Bond wrote:
> Hello Everyone,
> I had a question regarding IS-IS and TRILL. My apologies if this has been
> brought up in the past.
> Recently the follow comment was made:
> Perhaps the first sentence in Section 4.2.3 ("All Rbridges must
> participate in the TRILL IS-IS instance.") should have "which constitutes a
> single Level 1 IS-IS area using the fixed area-ID zero" appended to it.
> My question is, is there anything preventing layer 2 TRILL IS-IS from being
> configured as multiple level domain such as layer 3 IS-IS? This would break
> "zero configuration" but if some campus wished to have this additional
> control is there any reason why this could not be done? I also realize that
> TRILL is not meant to be any larger than existing layer 2 networks. So there
> might not be the desire for that additional control.
> David Bond
> Research and Development, Routing
> InterOperability Laboratory, University of New Hampshire
> rbridge mailing list
> rbridge at postel.org
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