Subject: [rbridge] Which 802.1 headers are relevant?

From: caitlinb at broadcom.com (Caitlin Bestler)
Date: Wed, 8 Nov 2006 14:51:14 -0800

I have a criteria to propose on the question of which L2 standards are
relevant to rbridges, versus being totally opaque.

The default for any L2 option that is not fully understood or yet
defined is covered by the general principle that to a bridge an
rbridge looks like a router.

That is, rbridges ignorant of 802.1??? will result in the cloud
being partitioned for purposes of 802.1??? -- and generally that
is the correct behavior.

For example, the value of 802.1x (Port-Based Network Access Control)
would not seem to be impaired by partitioning the cloud.

By contrast 802.1au (Congestion Avoidance) is clearly impaired
if BCNs cannot be delivered as close to the true source as possible.

I suggest that this be the criteria for determining which IEEE 
efforts are worth considering. More specifically, anyone who wishes
to discusss IEEE protocols (particularly those that are in progress)
needs to explain why rbridges being ignorant of said protocol would
produce a detrimental effect.

Once that case has been made, the WG can discuss mitigations including
possible new requirements for rbridges to properly support the 
specific IEEE protocol. Such requirements would probably need to
packaged in separate drafts, to prevent the main document being
dependent on different IEEE project's delivery schedules, which
probably also means that each feature set would be optional.
But I still think it would be of value for the trill WG to define
how an 802.1au-aware rbridge should handle each type of 802.1au
defined frames even if being 802.1au-aware is not required.

---

From: touch at ISI.EDU (Joe Touch)
Date: Wed, 08 Nov 2006 16:41:22 -0800

> rbridge looks like a router.

IMO, rbridges as a group look somewhat like a single bridge.

If they looked like a router, then traffic that transited them would be
addressed _to_ them at L2; this is never the case, so they're clearly
not routers.

> being partitioned for purposes of 802.1??? -- and generally that

The same could be said for bridges ignorant of 802.1?? - that they
partition, or more specifically 'are treated as air gaps' to that protocol.

The rest of the logic, I agree, follows... (if partitioning is OK, then
its OK; if not, then not).

Joe

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