Subject: I-D Action: draft-mathis-tcpm-proportional-rate-reduction-01.txt

From: [email-masked]
Date: Mon, 11 Jul 2011 15:06:37 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title           : Proportional Rate Reduction for TCP
	Author(s)       : Matt Mathis
                          Nandita Dukkipati
                          Yuchung Cheng
	Filename        : draft-mathis-tcpm-proportional-rate-reduction-01.txt
	Pages           : 16
	Date            : 2011-07-11

   This document describes an experimental algorithm, Proportional Rate
   Reduction (PPR) and related algorithms to improve the accuracy of the
   amount of data sent by TCP during loss recovery.  Standard Congestion
   Control requires that TCP and other protocols reduce their congestion
   window in response to losses.  This window reduction naturally occurs
   in the same round trip as the data retransmissions to repair the
   losses, and is implemented by choosing not to transmit any data in
   response to some ACKs arriving from the receiver.  Two widely
   deployed algorithms are used to implement this window reduction: Fast
   Recovery and Rate Halving.  Both algorithms are needlessly fragile
   under a number of conditions, particularly when there is a burst of
   losses that such that the number of ACKs returning to the sender is
   so small that the effective window falls below the target congestion
   window chosen by the congestion control algorithm.  Proportional Rate
   Reduction avoids these excess window reductions such that at the end
   of recovery the actual window size will be as close as possible to
   the window size determined by the congestion control algorithm.  It
   is patterned after rate halving, but using the fraction that is
   appropriate for target window chosen by the congestion control
   algorithm.  In addition we propose two slightly different algorithms
   to bound the total window reduction due to all mechanisms, including
   application stalls, the losses themselves and inhibit further window
   reductions when possible.

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This Internet-Draft can be retrieved at:
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