Quic Timestamps For Measuring One-Way Delays
draft-huitema-quic-ts-02

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Network Working Group                                         C. Huitema
Internet-Draft                                      Private Octopus Inc.
Intended status: Experimental                          February 29, 2020
Expires: September 1, 2020

              Quic Timestamps For Measuring One-Way Delays
                        draft-huitema-quic-ts-02

Abstract

   The TIME_STAMP frame can be added to Quic packets when one way delay
   measurements is useful.  The timestamp is set to the number of
   microseconds from the beginning of the connection to the time at
   which the packet is sent.  The draft defines the "enable_time_stamp"
   transport parameter for negotiating the use of this extension frame,
   and a new frame types for the time_stamped frame.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on September 1, 2020.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Measuring One-Way Delays  . . . . . . . . . . . . . . . . . .   2
     1.1.  Terms and Definitions . . . . . . . . . . . . . . . . . .   3
   2.  Specification . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Negotiation . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Sending TIME_STAMP frames . . . . . . . . . . . . . . . .   3
     2.3.  TIME_STAMP frame format . . . . . . . . . . . . . . . . .   4
     2.4.  RTT Measurements  . . . . . . . . . . . . . . . . . . . .   4
     2.5.  One-Way Delay Measurements  . . . . . . . . . . . . . . .   4
   3.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Management of Time  . . . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Measuring One-Way Delays

   The QUIC Transport Protocol [I-D.ietf-quic-transport] provides a
   secure, multiplexed connection for transmitting reliable streams of
   application data.  The algorithms for QUIC Loss Detection and
   Congestion Control [I-D.ietf-quic-recovery] use measurement of Round
   Trip Time (RTT) to determine when packets should be retransmitted.
   RTT measurements are useful, but there are however many cases in
   which more precise One-Way Delay (1WD) measurements enable more
   efficient Loss Detection and Congestion Control.

   An example would be the Low Extra Delay Background Transport (LEDBAT)
   [RFC6817] which uses variations in transmission delay to detect
   competition for transmission resource.  Experience shows that while
   LEDBAT may be implemented using RTT measurements, it is somewhat
   inefficient because it will cause unnecessary slowdowns in case of
   queues or delayed ACKs on the return path.  Using 1WD solves these
   issues.  Similar argument can be made for most delay-based
   algorithms.

   We propose to enable one way delay measurements in QUIC by defining a
   TIME_STAMP frame carrying the time at which a packet is sent.  The
   use of this extension frame is negotiated with a transport parameter,
   "enable_time_stamp".  When the extension is negotiated by both

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