[rbridge] it's time to summarize things

[Spencer Dawkins]

Dear All (following up from Radia's note),


>I just got back from a bunch of travel, and was trying to catch
> up on the mailing list, and it's really so long.
>
> It looks like the thread of whether RBridges participate
> in spanning tree popped up again. I thought that had been
> resolved.
>
> RBridges should NOT participate in spanning tree, which means
> they should DROP spanning tree messages.
>
> An RBridge should NOT merge spanning trees. It should terminate
> spanning trees, just like routers do.

I believe one idea has contributed to this - the idea that an RBRIDGE campus 
should look like a single very large bridge at its interfaces, which implies 
(in at least some e-mail) that it participates in the same spanning tree on 
both sides.

My apologies for cut-and-pasting, but the discussion has looked like this, 
in recent e-mail:

> --> > --> #1 resolve recommendations for the three modes of
> --> BSTP messages:
> --> > -->    (is this part of the PS or ARCH?)
> --> > --> participate
> --> > --> forward
> --> > --> block
> --> >
> --> > Block by default.  Optional configuration for forwarding and/or
> --> > participating MAY be allowed but SHOULD be considered sub-optimal.
> -->
> --> Forward maps to what hubs do.
> --> Participate maps to what bridges do.

My understanding of Radia's note is that an RBRIDGE campus looks like one 
very large router at its interfaces (no spanning tree, so no spanning tree 
merge).

If I am not misunderstanding Radia's note, I like this answer, because it 
looked like a lot of work to figure out what to do, in order to look like 
one very large bridge. If this is the high-order bit, things are clearer.

Am I reading the note correctly? And do others agree?

Spencer