Subject: [rbridge] 3 Week WG Last Call on draft-ietf-trill-rbridge-vlan-mapping-00.txt

From: Donald Eastlake <[email-masked]>
Date: Thu, 2 Apr 2009 15:37:55 -0400

Hi,

This message initiates a three week TRILL working group Last Call on
draft-ietf-trill-rbridge-vlan-mapping-00.txt, RBridge VLAN Mapping, as
discussed in San Francisco.

Donald and Erik (co-chairs)
=============================
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From: Donald Eastlake <[email-masked]>
Date: Tue, 14 Apr 2009 23:26:36 -0400

A point has been raised about section 7 of the draft. In particular, that
section assumes that a cut set RBridge can determine which region other
RBridges are in (east or west in the example in the Draft). But this is not
true in general.

Consider the following network:
      B
     / \
    X   A
   / \ /
  C   D
 / \
F---Y
     \
      E

Where X and Y are the cut set RBridges and they are implementing VLAN
mapping between RBridges to their right and those to their left. X and Y
have to know which region any directly connected RBridge is in because their
port have to be internally labeled for the region they connect to. So
cut-set RBridge Y knows the region of C, E, and F. But how is it going to
figure out the region of A? It doesn't even know that X is a cut-set
RBridge. And if we make the advertising of VLAN translation in its LSP by an
RBridge mandatory, instead of optional, (see section 4 of the draft) it
would then know that X was a cut-set RBridge but still not know the region
of A, B, and D because it does not know the labeling of the ports leading to
them internal to RBridge X.

It would seem that section 7 option "a)" needs to be changed to eliminate
the implication that a cut set RBridge can tell which region every other
RBridge is in.

Thanks,
Donald

--

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From: Donald Eastlake <[email-masked]>
Date: Thu, 16 Apr 2009 10:33:29 -0400

This is a reminder of the three week WG last call on
draft-ietf-trill-rbridge-vlan-mapping-00.txt, which has one week left
to run.

So far, two points have been raised:

(1) It is not generally possible for a cut-set RBridge to determine
which region of the campus another RBridge is in so section 7 need to
be modified to remove the assumption that this detmination can be
made.

(2) The draft should state that every port of a cut-set RBridge MUST
be classified as to the region to which it connects.

Thanks,
Donald