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<TITLE>RE: [e2e] a new IRTF group on Transport Models</TITLE>
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<P><FONT SIZE=2>Following up on Frank's question, one area where I suspect more data would help is in defining topologies to test TCP performance over. <BR>
<BR>
Most work to date has focussed on a dumbell topology. While this seems like a useful starting point, it would be good to have a better understanding of the range of end-to-end topologies experienced by TCP flows in practice. For example, it would be good to know what proportion of flows travel along paths where packets are queued at two or more hops (due to cross-traffic etc) and to better understand the character of such paths assuming they exist in appreciable numbers. This seems to require additional measurement information from that which is currently available - probing from the edge alone can probably only yield limited/ambiguous information on what's happening inside the network and so router information might help out a lot.<BR>
<BR>
Doug<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: end2end-interest-bounces@postel.org on behalf of frank@kastenholz.org<BR>
Sent: Wed 6/8/2005 1:49 PM<BR>
To: end2end-interest@postel.org<BR>
Subject: Re: [e2e] a new IRTF group on Transport Models<BR>
<BR>
While all this chatter about certain actions TCP can<BR>
or can not take and perfect nets with theorem<BR>
provers in all the routers is as interesting and<BR>
amusing as brain surgery, my original question stands:<BR>
<BR>
Is there any thought to identifying information<BR>
that routers and end systems might provide that<BR>
either can be fed back into the models to refine<BR>
them or used in parallel to (in)validate them?<BR>
<BR>
Frank Kastenholz<BR>
<BR>
<BR>
<BR>
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