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From: PIRARD%vm1.ulg.ac.be@CUNYVM.CUNY.EDU (Andr'e PIRARD)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  When is a link saturated?
Message-ID: <9102082241.AA00744@ucbvax.Berkeley.EDU>
Date: 8 Feb 91 09:59:53 GMT
References: <prindevi@INRIA.INRIA.FR>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 15

Up to recently, my opinion was that slower interfaces should have larger
amount of buffers in their output queues (or that a minimum reserved number
should be defined with a scheme for picking additional ones from a common
pool using up unallocated memory).
Now I read from Cisco's doc: "For slow links, use a small output queue
hold limit.". The only reason I see is avoiding retransmissions making the
congestion problem worse with duplicate packets. But I am not sure that,
as soon as a buffer of a congested small output queue becomes free, the next
datagram to fill it will not be retransmission anyway.
What is true? Are routers able to use techniques to match retransmissions
waiting in an output queue and discard the duplicate of a waiting datagram?

Andr'e PIRARD             SEGI, Univ. de Li`ege
B26 - Sart Tilman         B-4000 Li`ege 1 (Belgium)
pirard@vm1.ulg.ac.be  or  PIRARD%BLIULG11.BITNET@CUNYVM.CUNY.EDU