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        RFC 3522

        Title:      The Eifel Detection Algorithm for TCP
        Author(s):  R. Ludwig, M. Meyer
        Status:     Experimental
        Date:       April 2003
        Mailbox:    Reiner.Ludwig@eed.ericsson.se,
        Pages:      14
        Characters: 33729
        Updates/Obsoletes/SeeAlso:  None

        I-D Tag:    draft-ietf-tsvwg-tcp-eifel-alg-07.txt

        URL:        ftp://ftp.rfc-editor.org/in-notes/rfc3522.txt

The Eifel detection algorithm allows a TCP sender to detect a
posteriori whether it has entered loss recovery unnecessarily.  It
requires that the TCP Timestamps option defined in RFC 1323 be enabled
for a connection.  The Eifel detection algorithm makes use of the fact
that the TCP Timestamps option eliminates the retransmission
ambiguity in TCP.  Based on the timestamp of the first acceptable ACK
that arrives during loss recovery, it decides whether loss recovery
was entered unnecessarily.  The Eifel detection algorithm provides a
basis for future TCP enhancements.  This includes response algorithms
to back out of loss recovery by restoring a TCP sender's congestion
control state.

This document is a product of the Transport Area Working Group Working
Group of the IETF.

This memo defines an Experimental Protocol for the Internet community.
It does not specify an Internet standard of any kind.  Discussion and
suggestions for improvement are requested.  Distribution of this memo
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