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

From: [email-masked] (Noel Chiappa)
Date: Tue, 8 Nov 94 11:42:19 -0500

From: [email-masked] (Sally Floyd)

    I also like the redefinition of the router requirements document as
    defining a set of services ... without mandating universal deployment.
    ... recognizing that the major push for the deployment of new services
    will come from the users themselves.

One lemma of this line of thinking, one that you probably realize, but which
it's good to note explicity, is that it's going to be even more important that
the routing be able to find paths which even understand the kind of services
a given application requires. In an internetwork in which a given service is
only supported spottily (at best), path selection to transit those locales
is even more important.

Without an ability to get use out of a partial deployment of an enhanced
service model, there's not going to be a toehold to drive that further
deployment you posit.

	Noel

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From: Jon Crowcroft <[email-masked]>
Date: Wed, 09 Nov 94 08:58:33 +0000

>only supported spottily (at best), path selection to transit those locales

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 (c.f. paper by zheng wang in
prepaeration/awaiting jury...:-)

the trick is to do step 1 efficiently - but most networks are not
manhatten street grids, so the number of answers to step 1 is
relatively small (e.g. for UK US traffic right now, somewhere between
2 and 10...)

j.