Technical Summary
This document describes an algorithm to improve the accuracy
of the amount of data sent by TCP during loss recovery. The
existing TCP recovery algorithms can make excess window
adjustments in some situations, such as in the presence of
heavy losses, and may result in abrupt TCP behavior in the
form of packet bursts or increased risk of
timeouts. Proportional Rate Reduction aims to minimize the
needed window adjustments, to result in more stable TCP
congestion control behavior in the presence of losses.
Working Group Summary
The document was adopted as Experimental TCPM working group
item by clear working group consensus, and no opinions against
it have been raised during its progress or in the working
group last call.
Document Quality
The algorithm specified in the document has been implemented
in Linux and integrated to the main kernel distribution. The
algorithm has also been evaluated through measurements, and
the evaluation results reported in a paper published in the
IMC'11 conference. Different versions of the document have
been thoroughly reviewed by TCPM working group members.
Personnel
Document Shepherd is Pasi Sarolahti <pasi.sarolahti@iki.fi>.
Responsible Area Director is Wesley Eddy <wes@mti-systems.com>.
RFC Editor Note
(1)
Please change the Abstract to:
This document describes an experimental Proportional Rate Reduction
(PPR) algorithm as an alternative to the widely deployed Fast Recovery
and Rate Halving algorithms. These algorithms determine the amount
of data sent by TCP during loss recovery. PRR minimizes excess
window adjustments and the actual window size at the end of recovery
will be as close as possible to the ssthresh determined by the congestion control algorithm.
(2)
Please change all occurrences of "PPR" to "PRR".
(3)
Please change all occurrences of "PRR+SSRB" to "PRR-SSRB"
and all occurrences of "PRR+CRB" to "PRR-CRB"
(4)
On Page 3, please change:
"slight difference" to
"slight differences"
and
"discussions algorithms" to
"discussions of algorithms"
and
"of RFC 3517 we are" to
"of RFC 3517, we are"
(5)
On Page 11, please change:
"Bound in very" to
"Bound is very"