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From: craig@LOKI.BBN.COM.UUCP
Newsgroups: mod.protocols.tcp-ip
Subject: Analyzing Acknowledgement Strategies
Message-ID: <8612241633.AA10001@ucbvax.Berkeley.EDU>
Date: Wed, 24-Dec-86 11:33:59 EST
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Posted: Wed Dec 24 11:33:59 1986
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    Has anyone done any work analyzing acknowledgement strategies on
a theoretical level?

    It seems to me there is an inherent conflict in choosing acknowledgement
strategies.  To reduce unnecessary retransmissions of data packets, one
wants to make sure data packets get acknowledged.  But the best (only?)
way to make sure acknowledgements get through is to send more of them.

    It is easy to identify bad strategies.  A system which sends twenty
acknowledgements for every packet is a bad strategy because the number
of unneeded acknowledgements sent will clog a network more than the
reduction in unnecessary retransmissions (because an ack was lost)
could ever reduce network traffic.  Similarly, a system which acknowledges
too little abuses the network because too many data packets get
unnecessarily retransmitted -- up to a point acknowledging more often
will reduce the *total* number of packets sent.  (At least that's what
testing with RDP shows).

    The problem is identifying where these tradeoffs balance out --
where the range of optimal solutions lies (if anywhere) in this space.
Has anyone ever looked at this issue?

Craig