Transport Area

Directors
   o Allyn Romanow: allyn@eng.sun.com
   o Scott Bradner:  sob@harvard.edu

Meetings of nine Transport Area working groups and three BOFs were held
during the IETF meeting in Munich, Germany. 

avt - Audio/Visual Transport WG
The AVT working group had not planned to meet in Munich during a
period of dormancy while the testing of RTCP scaling mechanisms was
underway.  However, one AVT session was scheduled to discuss a new
problem with the RTCP scaling, plus open issues for several new payload
formats that were submitted since the last meeting.  The problem is a
relatively minor one: if many participants leave a session at once,
other participants that remain in the session may be falsely timed
out.  An extension to the "timer reconsideration" algorithm avoids
this timeout.  The new payload formats are for H.263+, MPEG4, BT-656
and QuickTime video, and DTMF tone signaling in audio.  In addition,
methods for repair of packet losses were discussed, including the
question of how much error correction is appropriate.  The meeting
concluded with an update on the RTP MIB and plans to implement it.

intserv - Integrated Services WG
The intserv WG held a meeting at the Munich IETF dedicated to the topic of
"differential services". The purposes of the meeting were to acquaint IETF
participants with current technical work in this area, to consider which
aspects of this technology require IETF standardization, and to discuss
what the IETF should do at this time.

The meeting heard presentations from Dave Clark, Van Jacobson, Kalevi
Kilkki, Fred Baker, and Ed Elleson, followed by a half hour of active
discussion. As an initial follow-on to the meeting, an internet draft
describing the similarities and differences of the approaches presented
will be prepared by the chair


ipc - Internet Policy Control BOF
The BOF discussed a charter for an IPC working group and came to some
conclusions including that the WG should focus on RSVP policy control
and not policies themselves.

Jim Boyle, MCI and David Durham, Intel presented a proposal for Client/Server
policy protocol (PEPCI), as a minimal functionality simpler alternative to 
the OOPS protocol.

Shai Herzog, IPHighway, presented the second version of OOPS (OOPS-01)
attempting to balance between simplicity, flexibility and scalability.

Tim O'mally agreed to be Chair of an IPC WG.


ippm - IP Performance Metrics BOF
The IPPM meeting was held 1PM - 3PM on Monday, August 11.  A major item of
business was discussing the draft charter for the proposed IPPM working
group, with the effort being moved from BMWG to the Transport Area in
recognition of the central role transport issues play in shaping many
Internet metrics. Considerable discussion centered around the word
"standard" and the degree to which it should apply to the IPPM charter and
the group's products. There was also discussion of the distinctions between
IPPM and other IETF efforts, such as OpStat, RTFM, and BMWG.  We then
reviewed near-final revisions to the Framework document, prior to
submitting it as an informational RFC.  This was followed by discussions of
operational experience with measuring one-way delays and packet loss, brief
discussion of updates to the Bulk Transfer Capacity I-D, and two further
experience talks, one on measurements of Internet telephony, and the other
on measuring packet loss and RTT using UDP echo packets.


issl - Integrated Services over Specific Link Layers WG
The ISSLL WG held two meetings at the Munich IETF. The primary purpose of
these meetings was to hold a full-group review a number of documents
prepared by the individual technology subgroups, before holding a WG
last-call on the mailing list. There are approximately 10 documents from
the IS802, ISATM, and ISSLOW subgroups nearing completion.

The second purpose of the meeting was to present some new work items
proposed since the last IETF, and see if the group wanted to proceed with
them. These items are ISATM extensions for "shortcuts" (NHRP); ISATM
extensions for server-based multicast (MARS/MCS), and the creation of a new
subgroup to consider IS over cable modem technology.

Finally, Raj Yavatkar gave a summary of integrated services and RSVP to the
IP1394 (IP over IEEE 1394 link layers) WG. Members of the IP1394 WG and the
ISSLL chairs discussed forming a IS1394 subgroup in the timeframe of the
Washington IETF.


mmusic - Multiparty multimedia Session Control WG
The MMUSIC WG had two meetings at the Munich IETF.  In the first
meeting Carsten Bormann briefly discussed the Internet Conferencing
Architecture the revised internet draft
(draft-ietf-mmusic-confarch-00.txt).  An archutecture for multicast
address address allocation was then presented by Mark Handley.  This
architecture is a three level model, with MDHCP being used to obtain
an address from a local server, the servers communicate using AAP
(Address Allocation Protocol), a proposed variant of SAP, and allocate
individual addresses from a range which is given to them by MASC, a
prefix allocation mechanism closely tied the BGMP (the Border Gateway
Multicast Protocol) beihng discussed in the IDMR WG.  Baiju Patel
presented MDHCP and Deborah Estrin briefly presented MASC.  All these
three protocols are strawmen at this time.  Mark Handley then
presented changes to the SIP specification since the Memphis IETF.

In the second meeting, Joerg Ott presented an update on the ITU-T work
that is related to MMUSIC.  Much of the session was taken up with Rob
Lanphier's discussion of the open issues related to RTSP, and good
progress was made.


nat - Network Address Translator BOF
Yakov Rekhter made a presentation defining NATs as a means of
interconnecting disparate routing realms. Multiple routing realms are a
reality and as such the IETF should address the reality. Specifically,
IPSEC should support communications spanning multiple routing realms.  In
response, Steve Bellovin felt that re-engineering IPSEC to cope with NAT
could mean lessening the overall security level between end nodes.  Steve
Deering presented slides pointing out that NAT can be pursued as a a
transition tool prior to deployment of IPv6, but pursuing NAT as a new
addressing architecture and an end-goal in itself is a bad idea and
significantly inferior to the current routing realm. 

Pyda Srisuresh presented the internet draft that extends RFC1631 to include
Network Address Port Translation (NAPT), which translates a pool of private
addresses into a single address for TCP/UDP applications. Suresh listed
requirements for NAT friendly applications and some of the security issues
NATs have to deal with for TCP and UDP applications. 

In the end, Scott Bradner, the area director, addressed the audience about
the rationale behind conducting the BOF and took a straw poll to assess the
interest in forming a NAT work group. There was overwhelming interest to
form a work group, in spite of reservations expressed by some.


pint - PSTN and Internet Interfaces WG
The newly-created PSTN/Internet Interworking (PINT) WG meeting took 
place from 15:30 to 17:30 on Wednesday, August 13. The meeting was chaired by 
Igor Faynberg (Bell Labs/Lucent Technologies).  The WG roster registers 131 
attendees. The meeting took place according to its agenda, which included
a discussion of the PINT Charter, a small tutorial on PSTN and IN, two presentations
on the PINT benchmark services and protocol, an introduction to the Session 
Initiation Protocol (SIP), and a discussion of the workplan.  The major
outcomes of the meeting were: 1)  agreement on the urgent need for security 
studies; 2)  agreement to study SIP on the subject of re-using it in
PINT; and 3) the priority of identifying the PINT services before the
protocol work starts. The initial outline of the Informational RFC was 
found acceptable as the starting point.

rsvp - Resource Reservation Setup Protocol WG
The RSVP working group met for one hour session in Munich.  After a brief
update on the status of the RSVP documents, currently being reviewed by the
IESG, and getting working group approval for a small addition to one of the
documents describing how the IANA should assign specific rsvp protocol
numbers, the working group discussed its future.  The result was a decision
that the working group will go dormant, since its work items have mostly
been accomplished or taken over by more specialized working groups.  The
rsvp mailing list will continue to be active.


rtfm - Realtime Traffic Flow Measurement WG
The WG reviewed its new charter.  Presentations were given on the current
meter implementations, and on three interesting research efforts.  The new
Meter MIB draft will go to WG last call before being submitted to the IESG
as a Proposed Standard.  The Architecture RFC needs small changes to bring
it into line with the new Meter MIB; this will be progressed as quickly as
possible.  Changes to the New Attributes draft were discussed, and several
interesting extensions proposed.  We aim to produce a final draft of the
New Attributes document for the December meeting.


tcpimpl - TCP Implementation WG 
The TCPIMPL meeting was held 7:30PM - 9PM on Monday, August 11.  We
estimate the audience at around 50-75 (plus MBone viewers).  The
meeting began with brief discussions of additions to the "known
problems" I-D, which included a description of some problems with
keep-alives, and a change in the use of "Significance" when describing
an implementation problem.  One of the authors of a new I-D cataloging
some TCP testing tools gave an overview of the I-D, eliciting
discussion about some possible additions.  We then engaged in lengthy
discussion of TCPIMPL undertaking the task to revise RFC 2001, both to
clarify (make less rigid) some of its wording, and to alter the
initial window used during slow-start.  Attendees debated the merits
and drawbacks to a number of different ways for altering congestion
control.  We finished with the usual plea for volunteers to document
other known TCP problems, and netted a few in the process.

tcpsat - TCP over Satellite WG
The TCPSAT WG met on Monday 1530-1730 in Munich. Scheduled topics
included a review of working group status by Aaron Falk (TRW, WG Chair)
and a briefing of the technical issues to be addressed in the working
group's I-D (Mark Allman, NASA) followed by open discussion.  The draft
scheduled to be released in July has not come out yet. To address this,
Mark Allman (NASA) has been added as a co-editor of the draft. 
Additionally, an interim meeting of the working group will be held in
October to help advance the draft to maintain the schedule.  The
technical presentation was prepared by Eric Travis (doc editor) and
included a summary of topics raised on the mail list as well as other
issues discovered by NASA. An interesting discussion occurred during
this presentation where Van Jacobson, Craig Partridge, and Tim Shepard
discussed the concept of increasing the time between TCP acknowledgments
as a method of improving performance under certain conditions.