Subject: I-D Action:draft-mathis-tcpm-proportional-rate-reduction-00.txt

From: [email-masked]
Date: Mon, 07 Mar 2011 15:15:03 -0800

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

	Title           : Proportional Rate Reduction for TCP
	Author(s)       : M. Mathis, et al.
	Filename        : draft-mathis-tcpm-proportional-rate-reduction-00.txt
	Pages           : 12
	Date            : 2011-03-07

This document describes a pair experimental algorithms, Proportional
Rate Reduction (PPR) and Reduction Bound (RB) that 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.  There are two widely deployed algorithms 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 delivered is so small that the effective window falls
below ssthresh, the target value 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 a second algorithm,
Reduction Bound, monitors the total window reduction due to all
mechanisms, including application stalls, the losses themselves and
inhibits further window reductions when possible.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-mathis-tcpm-proportional-rate-reduction-00.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the
Internet-Draft.