Subject: Re: mbone dvmrp/pim & congestion

From: [email-masked]
Date: Tue, 23 Sep 1997 12:55:15 -0700 (PDT)

> can i point people at the IRTF RM group now - this discussion (and

I will attempt to summarize a little so that those without an 
interest in Reliable Multicast (RM) per se need not join another 
list.

> several VERY promising solutions) are going on there more effectively
> - a meeting last week saw several people cover this excellently...and
> hopefully minutes will appear soon with pointers to the various
> papers - meanwhile
> [email-masked]
> will handle join requests and i guess has the list archive...

For those who are not up for joining another mailing list, 
the RM archive is at:

  http://irtf.cs.berkeley.edu/irtf/rm.html

I imagine that a subset of Mbone readers will want to follow
RM research.   This is what I have gathered that might be
of general interest relative to the rate/congestion control-
related issues. Some aspects of adaptive TCP-friendly rate/
congestion control appear to be covered in detail in numerous 
papers by Thierry Turletti, and many of his papers are accessible 
via the following web site:

  http://www.inria.fr/rodeo/turletti/me-noframe.html

  e.g. "`Experiments with a Layered Transmission Scheme 
        over the Internet", and, many other papers.

A couple of other web sites have related stuff, although,
the majority of it seems more oriented to relability part 
than the congestion-control part:

One web site, that of Frank Brockners, is mentioned in the
archive.   These papers are mostly/all in German:

  http://www.zpr.uni-koeln.de/~frank/publish.html

However, there is an interesting draft of a paper in English 
mentioned in the archive:

  http://www.zpr.uni-koeln.de/~frank/doc/cgn.ps.gz

Also, some of Luigi Rizzo's work seems to be related:

  http://www.iet.unipi.it/~luigi/fec.html

Finally, I would like to suggest that while adaptive rate/
congestion control for (reliable or unreliable) multicast/UDP 
that can peacefully coexist with TCP congestion control is 
certainly a necessary technology, and, may alleviate the stated
concerns about UDP apps breaking the internet etc, personally,
I don't consider it sufficient.  I still think that some kind
of (weighted "fair-share" RED) queuing is necessary also, and, 
the alternative to not developing intelligent queuing will be 
onerous per-packet/byte accounting...  [No need to recap again 
so soon.]

Additions/corrections/comments welcome.

-Hugh LaMaster

  Hugh LaMaster, M/S 258-5,     ASCII Email:  [email-masked]
  NASA Ames Research Center     Or:           [email-masked]
  Moffett Field, CA 94035-1000  No Junkmail:  USC 18 section 2701
  Phone:  415/604-1056          Disclaimer:   Unofficial, personal *opinion*.