Subject: Re: Some words from the cochairs...

From: [email-masked] (Sally Floyd)
Date: Mon, 07 Nov 94 15:27:59 PST

Scott -
I liked your recent note about the goals and process of the 
intserv working group.  I think it is a major step forward in 
the right direction.

I like the recognition of a heterogeneous Internet, with diverse subnet
technologies and different levels of service in different parts of the
internet, and the recognition that the services desired by applications are
likely to continue to evolve.  I also like the redefinition of the
router requirements document as defining a set of services (including
services for "best-effort" traffic) without mandating universal
deployment.  I am quite comfortable with seeing the role of the intserv
working group as providing coordination and guidance, while recognizing
that the major push for the deployment of new services will come from
the users themselves.

- Sally

In general, I also agree with Curtis's comments about the importance of
elastic traffic, the usefulness of link-sharing, and the necessity of
ensuring that this changing environment is one in which TCP can
continue to perform well.

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From: [email-masked] (Fred Baker)
Date: Wed, 9 Nov 1994 00:39:00 -0800

At 4:28 PM 11/8/94, Curtis Villamizar wrote:
>I don't seem to remember anone ever objecting to references to RSVP
>made in the WG.  Why the objections to TCP?

never mind. I was just observing on a fact that *I* have to live with,
whether you choose to live with it or not. Nothing to get ruffled about.

gee whiz...

=============================================================================
        If you're not living on the edge, you're taking up too much room!

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From: Scott Brim <[email-masked]>
Date: Wed, 9 Nov 1994 11:19:04 -0500

At 5:15 PM 11/7/94, Amit Gupta wrote:
  >1. In research, our decisions (and inferences) are based, to a large degree,
  >on the set of assumptions that we are willing to make; e.g. the telephone

Ahh, but this discussion is not taking place in a research forum.  This
is an IETF forum.  The overwhelming factor in the IETF is
responsiveness to the grubby imperfections of your environment, so you
can operate robustly (and if you're lucky, elegantly) in it.

...Scott

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From: [email-masked] (Noel Chiappa)
Date: Wed, 9 Nov 94 13:13:13 -0500

From: Jon Crowcroft <[email-masked]>

    seems to me there are only two sensible path seleciton criteria,
    before applying scheduling discipline to a flow 1/ select all paths with
    adequate thruput 2/ choose min acceptable end 2 end delay one of these.
    then use service discipline to select delay variance bound the application
    can tolterate
    anything else is np-difficult ... the trick is to do step 1 efficiently

You're already two steps past what I was saying!

I wasn't so much speaking to the particular algorithm used to select the path
(around which I expect we'll be working for years), as to recognition of the
fact that the basic routing architecture must allow use of such algorithms.
There is obviously some feedback from algorithms to architecture, and in fact
I expect that we will eventually decide that fully distributed algorithms to
do path selection (aka hop-by-hop routing) are not plausible in cases where
we want to specify service attributes.

All of which points me back to a basic architetural model for routing where
you distribute maps, and where path selection is a totally separate operation
which has a fair amount of interaction with resource mechanisms.

Which is a long way from Sally's original point, and I apologise to everyone
for going down a routing rat-hole!

	Noel

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From: [email-masked] (Noel Chiappa)
Date: Fri, 11 Nov 94 02:07:03 -0500

> TCP's VJCC may be a congestion control mechanism, but there's an
    > implicit resource allocation strategy hiding in there.
 
    no - TCP has a model of "given least information, how do we closest
    approximate fair share" ... it includes a meta-game theory which says 
    "if everyone weas trying to choose an algorithm to achiee this same
    goal, then what should i choose [being like them] to get the best for
    me"

What I meant with my comment was that the "fair share" goal was the implicit
resource allocation strategy; i.e. the strategy for allocation of resources is
to share them evenly.

	Noel