Additional negotiation in the TCP Timestamp Option field during the TCP handshake
draft-scheffenegger-tcpm-timestamp-negotiation-04

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TCP Maintenance and Minor Extensions                    R. Scheffenegger
(tcpm)                                                      NetApp, Inc.
Internet-Draft                                             M. Kuehlewind
Updates: 1323 (if approved)                      University of Stuttgart
Intended status: Experimental                              July 16, 2012
Expires: January 17, 2013

        Additional negotiation in the TCP Timestamp Option field
                        during the TCP handshake
           draft-scheffenegger-tcpm-timestamp-negotiation-04

Abstract

   A number of TCP enhancements in so diverse fields as congestion
   control, loss recovery or side-band signaling could be improved by
   allowing both ends of a TCP session to interpret the value carried in
   the Timestamp option.  Further enhancements are enabled by changing
   the receiver side processing of timestamps in the presence of
   Selective Acknowledgements.

   This documents updates RFC1323 and specifies a backwards compatible
   way of negotiating for Timestamp capabilities, and lists a number of
   benefits and drawbacks of this approach.

Status of this Memo

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Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal

Scheffenegger & Kuehlewind  Expires January 17, 2013            [Page 1]
Internet-Draft            Timestamp Negotiation                July 2012

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Overview of the TCP Timestamp Option . . . . . . . . . . . . .  6
   4.  Extended Timestamp Capabilities  . . . . . . . . . . . . . . .  7
     4.1.  Description  . . . . . . . . . . . . . . . . . . . . . . .  7
     4.2.  Timestamp clock interval exposure  . . . . . . . . . . . .  8
     4.3.  Timestamp echo update for Selective Acknowledgments  . . .  8
   5.  Timestamp capability signaling and negotiation . . . . . . . . 10
     5.1.  Capability Flags . . . . . . . . . . . . . . . . . . . . . 10
     5.2.  Timestamp clock interval encoding  . . . . . . . . . . . . 12
     5.3.  Negotiation error detection and recovery . . . . . . . . . 15
     5.4.  Interaction with Selective Acknowledgment  . . . . . . . . 17
       5.4.1.  Interaction with the Retransmission Timer  . . . . . . 18
       5.4.2.  Interaction with the PAWS test . . . . . . . . . . . . 19
     5.5.  Discussion . . . . . . . . . . . . . . . . . . . . . . . . 19
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
   7.  Updates to Existing RFCs . . . . . . . . . . . . . . . . . . . 20
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 21
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 22
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 22
     10.2. Informative References . . . . . . . . . . . . . . . . . . 22
   Appendix A.  Pseudo Code examples  . . . . . . . . . . . . . . . . 24
     A.1.  Sender . . . . . . . . . . . . . . . . . . . . . . . . . . 24
     A.2.  Receiver . . . . . . . . . . . . . . . . . . . . . . . . . 25
   Appendix B.  Possible use cases  . . . . . . . . . . . . . . . . . 26
     B.1.  One-way delay variation measurement  . . . . . . . . . . . 26
     B.2.  Timestamp clock rate exposure  . . . . . . . . . . . . . . 28
     B.3.  Early spurious retransmit detection  . . . . . . . . . . . 28
     B.4.  Early lost retransmission detection  . . . . . . . . . . . 29
     B.5.  Integrity of the Timestamp value . . . . . . . . . . . . . 31
     B.6.  Disambiguation with slow Timestamp clock . . . . . . . . . 31
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