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The NewReno Modification to TCP's Fast Recovery Algorithm

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: RFC Editor <>,
    tcpm mailing list <>,
    tcpm chair <>
Subject: Protocol Action: 'The NewReno Modification to TCP's Fast Recovery Algorithm' to Proposed Standard (draft-ietf-tcpm-rfc3782-bis-05.txt)

The IESG has approved the following document:
- 'The NewReno Modification to TCP's Fast Recovery Algorithm'
  (draft-ietf-tcpm-rfc3782-bis-05.txt) as a Proposed Standard

This document is the product of the TCP Maintenance and Minor Extensions
Working Group.

The IESG contact persons are Wesley Eddy and David Harrington.

A URL of this Internet Draft is:

Ballot Text

Technical Summary

From the abstract:

  RFC 5681 documents the following four intertwined TCP
  congestion control algorithms: slow start, congestion avoidance, fast
  retransmit, and fast recovery.  RFC 5681 explicitly allows
  certain modifications of these algorithms, including modifications
  that use the TCP Selective Acknowledgement (SACK) option (RFC 2883),
  and modifications that respond to "partial acknowledgments" (ACKs
  which cover new data, but not all the data outstanding when loss was
  detected) in the absence of SACK.  This document describes a specific
  algorithm for responding to partial acknowledgments, referred to as
  NewReno.  This response to partial acknowledgments was first proposed
  by Janey Hoe.  This document obsoletes RFC 3782.

Working Group Summary

Nothing exceptional occurred during the working group process for this

Document Quality

This document is an update to TCP NewReno, to address issues that
have been found with existing RFC 3782 implementations, of which
there are several.  In the Acknowledgments section:

  Many thanks to Anil Agarwal, Mark Allman, Armando Caro, Jeffrey Hsu,
  Vern Paxson, Kacheong Poon, Keyur Shah, and Bernie Volz for detailed
  feedback on this document or on its precursor, RFC 2582.  Jeffrey
  Hsu provided clarifications on the handling of the recover variable
  that were applied to RFC 3782 as errata, and now are in Section 8
  of this document.  Yoshifumi Nishida contributed a modification
  to the fast recovery algorithm to account for the case in which
  flightsize is 0 when the TCP sender leaves fast recovery, and the
  TCP receiver uses delayed acknowledgments.  Alexander Zimmermann
  provided several suggestions to improve the clarity of the document. 


David Borman ( is the document shepherd.  
Wes Eddy ( is the responsible AD.

RFC Editor Note