[Rmt] RMT meeting minutes (54th IETF, Yokohama)

[Lorenzo Vicisano <[e-mail]>]

minutes attached.

	regards,
	Lorenzo Vicisano


The RMT Working Group met in Yokohama on July 16th, 2002.

The meeting was opened with a summary report
on the WG status presented by Roger Kermode, followed by
update-presentations on the GRA signaling draft
(draft-ietf-rmt-bb-gra-signalling-00.txt), on WEBRC congestion control
(draft-ietf-rmt-bb-webrc-02.txt), on PGMCC congestion control
(draft-ietf-rmt-bb-pgmcc-01.txt) and on the NORM building block
(draft-ietf-rmt-bb-norm-04.txt). The meeting ended with a discussion on
the WG progress and on future plans.

The status-report was given by general protocol areas: most of the
ALC-related drafts are undergoing IESG review following the submission
as experimental RFCs. The only non-ready draft in this area is the
congestion control one (draft-ietf-rmt-bb-webrc-02.txt). Some of the
ALC drafts under IESG examination are also part of the NORM protocol.
The main drafts related to NORM are in good status of advancement
(draft-ietf-rmt-bb-norm-04.txt and draft-ietf-rmt-pi-norm-04.txt). As
for the congestion control for NORM, PGMCC
(draft-ietf-rmt-bb-pgmcc-01.txt) is current and almost complete while
TFMCC is expired. However the last submitted version of TFMCC was
almost complete.  All the drafts specifically intended for the TRACK
protocol are expired and none of the authors was present at the
meeting [more on this later]. Finally the work on GRA has just
restarted and it is still at an early stage.

Tony Speakman discussed the advancement on GRA signaling. The GRA
signaling draft, that will be submitted to the IETF directory after
the meeting, concentrates on a general framework for end-host to
request network elements to execute GRA function. The specific GRA
functions are to be defined in separate specification(s). The
presentation was followed by a technical discussion on the draft
content, with two main hilights: the G-bit used to detect the GRA
header in transport packet formats needs to be considered by the other
authors of RMT protocol specifications, and the granularity used by
the draft to describe network-element functions might be revised (made
finer). Also the future of the other two GRA drafts that are expired
was discussed. These will not be resubmitted in the short term, but
might be updated at a later stage, with the intent of providing
information on the GRA framework (the intended outcome is
informational RFCs).

Mike Luby presented an update on the WEBRC congestion control. This
congestion control scheme is also discussed in a technical paper to
appear in the proceedings of Sigcomm'2002. NS code will be available
by August 1, some simulations in real networks have already been done
but there is a need to do real-world experiments. The goal is
for this to be an RFC by March 2003 at the earliest.

Gianluca Iannaccone gave a brief update on PGMCC, that was revised to
comply with the 'author guidelines" document and to fix some technical
details. Next step is to develop more on the interaction between PGMCC
and feedback suppression mechanisms. Two additional action-items for
the draft authors came from the discussion: add a description of a
possible attack from a malicious receiver that causes itself to be
elected as the "acker" by sending a large amount of NAKs, but then
drives the session rate up by ACKing in an inconsistent way. The
specification should require implementors to protect the network
against this type of attack through heuristics that compare the
loss-rate reported by NAKs and the one inferred from ACKs. The other
action item was to experiment with the protocol in real networks.

Brian Adamson gave updates on the NORM BB draft and presented some
simulation results (the code of his simulation experiments is shared
with the reference implementation that he has). Next steps are:
collecting more feedback from the WG, working on congestion control
support (both TFMCC and PGMCC) and GRA support. There was some
feedback on the NORM document structure: Roger Kermode suggested to
revise it to comply to the RMT authors' guidelines, Tony Speakman to
move the content around between the BB and the PI document to improve
modularity and chance of BB reuse.

An evaluation of the WG status an discussion on future action items
closed the meeting.

Most of the work in the charter is close to completion with the
exception of the TRACK protocol and GRA.

As for TRACK, it was not possible to collect information on the
authors' intentions, as none of them was present, however the feeling
of the WG was that the status of the work is probably an
indication of lack of interest in pursuing it further. The plan is to
stop the work on TRACK and change the WG charter accordingly, unless
there is a clear indication/commitment from the TRACK authors.

The work on GRA is being carried on but is substantially behind
compared to the rest, hence the WG will proceed towards the publication
of the various BBs and PIs as Experimental RFC. If GRA is not ready at
the time of the publication, the final integration work will be done in a
later revision of the specs.

Finally two possible new working items for the WG were discussed.  The
first was a session control protocol, the action item was to form a
team to gather requirements, before making any decision on whether
this work should be done in the WG or not. Mike Luby volunteered to
lead the effort with the help of Tony Speakman and Roger Kermode.

The second proposal was to open the WG to non-one-to-many RMTs. The WG
orientation was not to pursue it at this time. The rationale behind
this decision was to have time to consolidate the results currently
achieved and observe how deployment plays out, before starting to
standardize new pieces of work.


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