Subject: I-D Action:draft-zimmermann-tcp-lcd-02.txt

From: [email-masked]
Date: Wed, 26 Aug 2009 06:30:01 -0700 (PDT)

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

	Title           : Make TCP more Robust to Long Connectivity Disruptions
	Author(s)       : A. Zimmermann, A. Hannemann
	Filename        : draft-zimmermann-tcp-lcd-02.txt
	Pages           : 17
	Date            : 2009-08-26

Disruptions in end-to-end path connectivity which last longer than
one retransmission timeout cause suboptimal TCP performance.  The
reason for the performance degradation is that TCP interprets segment
loss induced by connectivity disruptions as a sign of congestion,
resulting in repeated backoffs of the retransmission timer.  This
leads in turn to a deferred detection of the re-establishment of the
connection since TCP waits until the next retransmission timeout
occurs before attempting the retransmission.

This document describes how standard ICMP messages can be exploited
to disambiguate true congestion loss from non-congestion loss caused
by long connectivity disruptions.  Moreover, a revert strategy of the
retransmission timer is specified that enables a more prompt
detection of whether the connectivity to a previously disconnected
peer node has been restored or not.  The specified algorithm is a TCP
sender-only modification that effectively improves TCP performance in
presence of connectivity disruptions.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-zimmermann-tcp-lcd-02.txt

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

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