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<TITLE>RE: [e2e] trading acks...TRACKS</TITLE>
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<P><FONT SIZE=2>If a packet can't enter the network until one has left, how do<BR>
you ever get started in an empty totally quiet network? Simple<BR>
reductio ad absurdum suggests that the packet conservation<BR>
principle as expressed below is bogus. Not so much isarithmic,<BR>
as isacrock.<BR>
<BR>
However, packet conservation through a router is something that<BR>
can be aspired to, under limited conditions - thinking about<BR>
a networking analogue of Kirchoff's electrical laws through the<BR>
router as a point can actually be useful, too.<BR>
<BR>
L.<BR>
<BR>
odd to see someone actually mention they're working on TSAT...<BR>
<BR>
<<A HREF="http://www.ee.surrey.ac.uk/Personal/L.Wood/">http://www.ee.surrey.ac.uk/Personal/L.Wood/</A>><L.Wood@surrey.ac.uk><BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: end2end-interest-bounces@postel.org on behalf of Joe Touch<BR>
Sent: Fri 2006-12-01 23:29<BR>
To: Christian Kreibich<BR>
Cc: Jon Crowcroft; end2end-interest@postel.org<BR>
Subject: Re: [e2e] trading acks...TRACKS<BR>
<BR>
Christian Kreibich wrote:<BR>
> Hi Detlef,<BR>
><BR>
> On Sat, 2006-11-25 at 17:49 +0100, Detlef Bosau wrote:<BR>
>> just a very spontaneous, perhaps stupid, question: What is the<BR>
>> difference between "packet symmetry" and the well known principle of<BR>
>> packet conservation here? Aren´t these ideas at least quite similar?<BR>
><BR>
> the packet conservation principle states that in a steady-state TCP<BR>
> flow, a new packet is not to enter the network before another one has<BR>
> left<BR>
<BR>
That "packet conservation principle" already has a (perhaps not as<BR>
well-known, but certainly worth knowing) name: 'isarithmic', and was<BR>
proposed by Davies in 1972.<BR>
<BR>
"Packet symmetry" appears to be per-NIC isarithmic.<BR>
<BR>
The "packet conservation principle" is single-protocol isarithmic.<BR>
<BR>
Joe<BR>
<BR>
--<BR>
----------------------------------------<BR>
Joe Touch<BR>
Sr. Network Engineer, USAF TSAT Space Segment<BR>
<BR>
<BR>
<BR>
<BR>
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