Subject: network conscious applications and service model

From: Jon Crowcroft <[email-masked]>
Date: Thu, 20 Jul 95 11:01:22 +0100

driving a service model from thinking about what an application could
actually use, i think what I'd like for workstation based multimedia
applciations is the following

1. a minimum rate, for which the delay is effectively tyhe propogation
time plus 1 packets queuing time at each hop (can you do any
better?:-)

plus

2. an adaption ceiling for which i (as the application writer) specify
loss or delay tolerance and a preference (to be implemented i don't
care how....but gives leaway to people to mark or drop, buffer or
reroute or serve in a different class)

plus

3. a liteweight renegotiation of the minimum rate (with no RTT delay before 
i get it, unless i don't get it:-)

this doesn't seem to me to correspond with any of the current 
offerings (or the ATM ABR or VBR services)

i know i could tag my packets from a single sourcedifferently (e.g.
some as CBR, some as VBR some as ABR, oops sorry, some as guaranteed,
some controlled, some predictive etc etc) but i don't want to...in any
case, in both ATM and int-serv models, i'd need multiple VCs (sorry,
RSVP flow setups)...but a flow might correspond to a scarce resource
(vci or class in a switch or router...)

what do we think.....

jon