Subject: [mpls-tp] MEAD review of GACH-DCN

From: "Adrian Farrel" <[email-masked]>
Date: Sat, 25 Jul 2009 14:19:47 +0100

All,

Attached are my notes from the MEAD team review of 
draft-ietf-mpls-tp-gach-dcn-03.txt.

Forwarding these to everyone for information and so you can see what changes 
are planned for the next revision.

Happy to have comments from anyone at any time.

Cheers,
Adrian

===

1. Update the whole document on the assumption that layer 3 forwarding of
packets received on the ECC is allowed.

2. Add description of G-ACh being a supplement to in-fiber layer 3 (mixed
with MPLS), out-of-band connectivity, and connectivity achieved through a
separate infrastructure.

3. Explain that connectivity is allowed using the G-ACh associated with an
LSP, PW, or physical link. Say that the normal behavior is expected to be to
use the physical link G-ACh for connectivity between physically adjacent
nodes. Nodes connected by logical links (realised by LSPs or PWs) may
communicate directly using the G-ACh associated with the relevant LSP or PW.
Non-adjacent nodes may communicate using a network (the DCN) constructed
from G-ACh links using layer 3 forwarding at transit nodes - such a network
might be achieved using default routes (for example on a ring), or by
running a layer 3 routing protocol within the DCN.

4. Raise question on mailing list about whether 32bit alignment is needed.
Coordinate with Stewart's ACH TLV I-D if necessary.

5. Make it so the ACH PID TLV is the last one present in the list of TLVs
for messages on the DCN so that the PID is immediately adjacent to the DCN
message.

6. State that no other TLVs have been identified for use in this context.
Explain the behavior if another TLV is received. Viz: "If a TLV is received
that is not understood in the context of a DCN message, the TLV SHOULD be
silently ignored and processing of the message SHOULD continue."

7. Add some text to clarify the meaning of "associated channel" (in 
association with point 3). Discussion of this may be lifted from Appendix A 
of draft-ietf-mpls-tp-nm-req.