Internet Standards/CD1.mdf/INET/IETF/94MAR/TRANSPRT

Text File | 1994-06-07 | 7.8 KB | 180 lines

Transport Area

Director:


   o Allison Mankin:  [e-mail]


Area Summary Reported by Allison Mankin/NRL

The Transport Area Directorate is comprised of the following members:
Dave Borman, Sally Floyd, Jim Hughes, Matt Mathis, Greg Minshall, Eve
Schooler, and John Wroclawski.

The Transport Services Area deals with protocols and algorithms that
provide end-to-end transmission services in the Internet.  We maintain
the notion of transport services, not just transport protocols, because
of the increasing variety of end-to-end requirements that the Internet
is meeting, or will be expected to meet, in the near future.

In the month after the Seattle IETF, two working groups were added to
Transport Services because of the closing down of the Service
Applications Area:  ONCRPC and THINOSI. They are covered in the SAP
report for Seattle, but they fit well into the Transport Area Director
and Directorate's sense of the scope of the Transport Services Area.

Since the last report, we have increased the directorate, reflecting
both the increase in the number of our active working groups and the
area director's temporary assignment to co-direct the IP: Next
Generation Area (with Scott Bradner).  The directorate is primarily
responsible for quality review of the working groups.  They also
contribute to our planning with their diverse and far-sighted
perspectives on the Internet.

Among the future issues for TSV that we are thinking on are:  improving
distributed file systems, fully documenting as standards TCP's adaptive
algorithms (for the moment, Sally Floyd reports that the account in
Richard Steven's TCP/IP Illustrated 2nd Edition will be correct and
complete), completing selective acknowledgment in TCPLW, and developing
an informational activity on the integrated layer processing technique,
which is strongly related to transport services implementation issues.

The Transport Services Area working groups that met in Seattle offer
their brief summaries below.  INT-SERV met as a BOF in Seattle, but it
has since become a working group.  ONCRPC is included in the SAP report
for Seattle.


Audio/Video Transport Working Group (AVT)

The meeting began with a brief report on the status of the Real-time
Transport Protocol (RTP). The draft RTP specification was submitted with
a request for Last Call just before the previous IETF meeting in
November.  The review by the Transport Area Directorate called for
several changes so that RTP would more closely follow the principles of
application level framing.  In two discussions between Steve Casner, Ron
Frederick and Van Jacobson in which the vat and nv programs were taken
as design examples, the following list of proposed changes was
constructed:


   o Carry the control and data traffic on separate ports

   o Move the application-level multiplexing of the channel ID to an
     encapsulation, for the cases where it is needed

   o Minimize the use of options

   o Make the definition of some fields application-specific (in
     particular, the timestamp clock rate and sync marker)

   o Use global rather than local IDs, to be able to detect loops

   o Specify more precisely how reception reports should be provided


The first 90 minutes of the first session, and the beginning of the
second session were occupied by a presentation of these changes.  The
attendees generally agreed with the changes, and in particular agreed
that the global identifiers would always be 32-bit random numbers rather
than allowing the IPv4 address to be used as an identifier; as a
consequence, the identifier of the synchronization source will always be
included in a new field added to the fixed RTP header.  There are
several details remaining to be defined, in particular the mechanisms
for padding the message to a multiple of the encryption block size, and
for carrying the authentication information, and the exact structure of
the control packet.

Our task now is to complete the design to address these details, update
the specification and get consensus from the working group via e-mail.
Steve Casner will take responsibility for sending out a more complete
draft of the proposed changes to start the discussion.  The goal is to
submit the draft for Last Call after review at the July IETF meeting in
Toronto.


Integrated Services Working Group (INTSERV)

The first meeting was an organizational meeting, describing the
motivations for the group, its organization, and timeline.  The goal of
INTSERV is to make the Internet friendly to real-time applications
(e.g., multimedia conferencing) by enhancing the Internet architecture
to support integrated services.

The proposed working group organization calls for Craig Partridge to be
the working group chair, and John Wroclawski, Scott Shenker and Dave
Clark to be co-chairs.  It was explained that the large management team
is intended to ensure that the necessary outreach to various affected
communities is made.

The working group timeline calls for delivery of several RFCs over the
next two years.

The second session was devoted to trying to investigate what
requirements integrated services might place upon IPng.  Craig explained
that this was definitely putting the cart before the horse, given that
the group had barely had a chance to talk about proposed integrated
services architectures, but at the request of the IPng Directorate, a
discussion was held.

At the end of the meeting, the proto-working group concluded that there
were two requirements it would like to place on IPng:


   o That an IPng have some mechanism to locate per-datagram
     classification information (e.g., flow state) and that the
     mechanism should be consistent with forwarding at the media speeds
     expected in the future.

   o That an IPng should have mechanisms to hinder Bob from using or
     disrupting resources that Alice has been granted and is using.


Craig Partridge was tasked to write up these points and circulate a
draft to the working group, for consideration as submission as a white
paper to the IPng directorate.



Multiparty Multimedia Session Control Working Group (MMUSIC)


During the Seattle meetings of the MMUSIC Working Group, there appeared
to be a convergence of ideas about the general framework and protocols
required for session control in the Internet, and a readiness to take
steps toward interoperability of existing applications.  The group
identified at least two services that system builders might need and
use; CCCP, a bus-based protocol that could provide an API-level
messaging abstraction, and the agreement algorithm on which a session
service could be built.  In addition, there was interest in trying to
understand, in the present context of the Internet/MBone/WWW, what
constitutes a session and what are the functions that can be performed
on sessions once they exist.  Thus, a variety of session rendez-vous
mechanisms were described.  A final discussion focused on the relevance
of reliable multicast to a membership management protocol.  From formal
and informal conversations with working group participants, it was clear
that these ideas are ready to be codified and written down.



Resource Reservation Setup Protocol Working Group (RSVP)

The RSVP Working Group met twice during the Seattle IETF. The first
session was devoted to an overview of the protocol and a report on the
status of an initial implementation.  Several issues were raised and
discussed.  The second session was largely devoted to further discussion
of a number of basic issues.

The working group plans to hold an MBone conference before the next IETF
meeting (the MBone meeting has been scheduled for 23 June), and to
conduct further discussion by e-mail.  There were several action items
to prepare position papers on particular issues.  The draft
specification will be updated with some additions suggested at the
meeting.

Many of the hard issues under discussion concerned functional
modularity, especially between resource reservation and routing.