rfc3042.txt

最新的RFC

   the TCP sender, and does not seem necessary.

   The most important protection against false duplicate ACKs comes from
   the limited potential of duplicate ACKs in subverting end-to-end
   congestion control.  There are two separate cases to consider: when
   the TCP sender receives less than a threshold number of duplicate
   ACKs, and when the TCP sender receives at least a threshold number of
   duplicate ACKs.  In the latter case a TCP with Limited Transmit will
   behave essentially the same as a TCP without Limited Transmit in that
   the congestion window will be halved and a loss recovery period will
   be initiated.

   When a TCP sender receives less than a threshold number of duplicate
   ACKs a misbehaving receiver could send two duplicate ACKs after each
   regular ACK.  One might imagine that the TCP sender would send at
   three times its allowed sending rate.  However, using Limited
   Transmit as outlined in section 2 the sender is only allowed to
   exceed the congestion window by less than the duplicate ACK threshold
   (of three segments), and thus would not send a new packet for each
   duplicate ACK received.







Allman, et al.              Standards Track                     [Page 5]

RFC 3042              Enhancing TCP Loss Recovery           January 2001


Acknowledgments

   Bill Fenner, Jamshid Mahdavi and the Transport Area Working Group
   provided valuable feedback on an early version of this document.

References

   [Bal98]   Hari Balakrishnan.  Challenges to Reliable Data Transport
             over Heterogeneous Wireless Networks.  Ph.D. Thesis,
             University of California at Berkeley, August 1998.

   [BPS+97]  Hari Balakrishnan, Venkata Padmanabhan, Srinivasan Seshan,
             Mark Stemm, and Randy Katz.  TCP Behavior of a Busy Web
             Server:  Analysis and Improvements.  Technical Report
             UCB/CSD-97-966, August 1997.  Available from
             http://nms.lcs.mit.edu/~hari/papers/csd-97-966.ps.  (Also
             in Proc. IEEE INFOCOM Conf., San Francisco, CA, March
             1998.)

   [BPS99]   Jon Bennett, Craig Partridge, Nicholas Shectman.  Packet
             Reordering is Not Pathological Network Behavior.  IEEE/ACM
             Transactions on Networking, December 1999.

   [FF96]    Kevin Fall, Sally Floyd.  Simulation-based Comparisons of
             Tahoe, Reno, and SACK TCP.  ACM Computer Communication
             Review, July 1996.

   [Flo94]   Sally Floyd.  TCP and Explicit Congestion Notification.
             ACM Computer Communication Review, October 1994.

   [Jac88]   Van Jacobson.  Congestion Avoidance and Control.  ACM
             SIGCOMM 1988.

   [LK98]    Dong Lin, H.T. Kung.  TCP Fast Recovery Strategies:
             Analysis and Improvements.  Proceedings of InfoCom, March
             1998.

   [MSML99]  Matt Mathis, Jeff Semke, Jamshid Mahdavi, Kevin Lahey.  The
             Rate Halving Algorithm, 1999. URL:
             http://www.psc.edu/networking/rate_halving.html.

   [Mor97]   Robert Morris.  TCP Behavior with Many Flows.  Proceedings
             of the Fifth IEEE International Conference on Network
             Protocols.  October 1997.

   [NS]      Ns network simulator.  URL: http://www.isi.edu/nsnam/.





Allman, et al.              Standards Track                     [Page 6]

RFC 3042              Enhancing TCP Loss Recovery           January 2001


   [PA00]    Paxson, V. and M. Allman, "Computing TCP's Retransmission
             Timer", RFC 2988, November 2000.

   [Riz96]   Luigi Rizzo.  Issues in the Implementation of Selective
             Acknowledgments for TCP.  January, 1996.  URL:
             http://www.iet.unipi.it/~luigi/selack.ps

   [SA00]    Hadi Salim, J. and U. Ahmed, "Performance Evaluation of
             Explicit Congestion Notification (ECN) in IP Networks", RFC
             2884, July 2000.

   [SCWA99]  Stefan Savage, Neal Cardwell, David Wetherall, Tom
             Anderson.  TCP Congestion Control with a Misbehaving
             Receiver.  ACM Computer Communications Review, October
             1999.

   [RFC793]  Postel, J., "Transmission Control Protocol", STD 7, RFC
             793, September 1981.

   [RFC2018] Mathis, M., Mahdavi, J., Floyd, S. and A. Romanow, "TCP
             Selective Acknowledgement Options", RFC 2018, October 1996.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2481] Ramakrishnan, K. and S. Floyd, "A Proposal to Add Explicit
             Congestion Notification (ECN) to IP", RFC 2481, January
             1999.

   [RFC2581] Allman, M., Paxson, V. and W. Stevens, "TCP Congestion
             Control", RFC 2581, April 1999.

   [RFC2582] Floyd, S. and T. Henderson, "The NewReno Modification to
             TCP's Fast Recovery Algorithm", RFC 2582, April 1999.

   [ZQ00]    Yin Zhang and Lili Qiu, Understanding the End-to-End
             Performance Impact of RED in a Heterogeneous Environment,
             Cornell CS Technical Report 2000-1802, July 2000.  URL
             http://www.cs.cornell.edu/yzhang/papers.htm.












Allman, et al.              Standards Track                     [Page 7]

RFC 3042              Enhancing TCP Loss Recovery           January 2001


Authors' Addresses

   Mark Allman
   NASA Glenn Research Center/BBN Technologies
   Lewis Field
   21000 Brookpark Rd.  MS 54-5
   Cleveland, OH  44135

   Phone: [phone]
   Fax:   [phone]
   EMail: [e-mail]
   http://roland.grc.nasa.gov/~mallman


   Hari Balakrishnan
   Laboratory for Computer Science
   545 Technology Square
   Massachusetts Institute of Technology
   Cambridge, MA 02139

   EMail: [e-mail]
   http://nms.lcs.mit.edu/~hari/


   Sally Floyd
   AT&T Center for Internet Research at ICSI (ACIRI)
   1947 Center St, Suite 600
   Berkeley, CA 94704

   Phone: [phone]
   EMail: [e-mail]
   http://www.aciri.org/floyd/



















Allman, et al.              Standards Track                     [Page 8]

RFC 3042              Enhancing TCP Loss Recovery           January 2001


Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















Allman, et al.              Standards Track                     [Page 9]