Subject: [rbridge] Sec 2.3 in draft-touch-trill-rbridge-prob-00

From: akatlas at gmail.com (Alia Atlas)
Date: Wed, 9 Nov 2005 10:29:29 -0800

"It would be more useful for subnet configuration to be tolerant of
   such transients, e.g., supporting alternate, backup paths.

   [QUESTION: is there more to say here?]

   Contrast this to network layer intradomain and interdomain routing,
   both of which include provisions for backup paths. These backups
   allow routing to be more stable in the presence of transients, as
   well as to recover more "rapidly when the transient disappears. "

I found the description here to be rather confusing.  Are you saying
that the possibility for the use of additional links permits easier
routing convergence?  Or are you suggesting that
alternate next-hops can be pre-computed and used on a failure - as is
described in the IP fast-reroute work in rtgwg?  I'd assume the
former.  If that's the case, then I think the language needs some
clarification.

Alia

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From: gibanez at it.uc3m.es (Guillermo Ibáñez)
Date: Wed, 09 Nov 2005 21:14:25 +0100

>former.  If that's the case, then I think the language needs some
May be the terminology is confusing, but it is a must to obtain fast 
reconfiguration as required by rbridges.
(I will be again advocate of RSTP as example, that includes alternate 
port role, able to be root port via different path to root bridge,  for 
faster reconfiguration.

>Alia
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From: akatlas at gmail.com (Alia Atlas)
Date: Wed, 9 Nov 2005 13:24:54 -0800

> port role, able to be root port via different path to root bridge,  for

What times do you define as fast reconfiguration?  If there's interest in
using alternates such as in IP FRR, that could help; it may also add some
complexity.

Alia

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From: gibanez at it.uc3m.es (Guillermo Ibáñez)
Date: Wed, 09 Nov 2005 22:41:03 +0100

>using alternates such as in IP FRR, that could help; it may also add some
Less than about one second seems acceptable for campus networks. 
Although tenths of milliseconds would be preferable.
Guillermo