Subject: [rbridge] routing heirarchy discussion in draft-touch-trill-rbridge-prob-00.txt

From: akatlas at gmail.com (Alia Atlas)
Date: Wed, 9 Nov 2005 09:34:33 -0800

Sec 2.2 says:

"The spanning tree protocol is inherently global to an entire layer 2
   subnet; there is no current way to contain, partition, or otherwise
   factor the protocol into a number of smaller, more stable subsets
   that interact as groups. Contrast this with Internet routing, which
   includes both intradomain and interdomain variants, split to provide
   exactly that containment and scalability within a domain while
   allowing domains to interact freely independent of what happens
   inside.  "

I think that one strength of rbridges is the potential for introducing
a level of heirarchy in the routing.  However, I believe this is confined
to IGP-like areas (intra-domain).  The idea of nesting inter-domain
heirarchy inside seems rather implausible.

If we are considering routing areas, then it may also be interesting to
consider or at least discuss the topology constraints required in order
to support such.

Alia

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From: gibanez at it.uc3m.es (Guillermo Ibáñez)
Date: Wed, 09 Nov 2005 21:00:13 +0100

>   allowing domains to interact freely independent of what happens
This statement is not completely true, as Multiple Spanning Tree 
Protocol allows the definition of regions
where independent trees are contained and partitioned.

>consider or at least discuss the topology constraints required in order
Regarding introducing hierarchy, a second level of spanning trees 
(double L2 encapsulated as well inside a confined core region with 
multiple spanning trees,  each tree rooted at edge bridges) is also a 
way to introduce hierarchy and hence obtain scalability
Guillermo

>Alia
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>  
>

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From: akatlas at gmail.com (Alia Atlas)
Date: Wed, 9 Nov 2005 13:29:28 -0800

Could you send me a pointer to the ref on this work?  I'd be
interested in taking
a look.  Maybe we could come up with a more accurate statement - both
of what is possible and what improvements trill might be able to
provide.

Alia

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From: gibanez at it.uc3m.es (Guillermo Ibáñez)
Date: Thu, 10 Nov 2005 10:27:54 +0100

IEEE 802.1Q  Multiple Spanning Tree Protocol. 
Tutorial available : "Understanding Multiple Spanning Tree Protocol" at 
www.cisco.com
Regards
Guillermo