The Transport-Info HTTP Header
draft-ohanlon-transport-info-header-01

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HTTP                                                         P. O'Hanlon
Internet-Draft                                              J. Gruessing
Intended status: Standards Track        British Broadcasting Corporation
Expires: September 4, 2020                                 March 3, 2020

                     The Transport-Info HTTP Header
                 draft-ohanlon-transport-info-header-01

Abstract

   The Transport-Info header provides a mechanism to transmit network
   transport related information such as current delivery rate and
   round-trip time, from a server or a client.  This information has a
   wide range of uses such as client monitoring and diagnostics, or
   allowing a client to adapt to current network conditions.

Note to Readers

   _RFC Editor: please remove this section before publication_

   Source code and issues for this draft can be found at
   https://github.com/bbc/draft-ohanlon-transport-info-header [1].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 4, 2020.

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   Copyright (c) 2020 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
   Provisions Relating to IETF Documents

O'Hanlon & Gruessing    Expires September 4, 2020               [Page 1]
Internet-Draft            Transport-Info Header               March 2020

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.3.  Notational Conventions  . . . . . . . . . . . . . . . . .   4
   2.  The Transport-Info HTTP Header  . . . . . . . . . . . . . . .   4
     2.1.  Utilisation of Transport-Info header metrics  . . . . . .   6
   3.  Server based behaviour  . . . . . . . . . . . . . . . . . . .   7
   4.  Client based behaviour  . . . . . . . . . . . . . . . . . . .   7
     4.1.  Client side proxy considerations  . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
     6.1.  Privacy Considerations  . . . . . . . . . . . . . . . . .   8
     6.2.  Information control . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  10
     7.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  11
   Appendix B.  Changes  . . . . . . . . . . . . . . . . . . . . . .  11
     B.1.  Since -00 . . . . . . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   The Transport-Info header provides for relaying of transport protocol
   related information from either a server or client entity with the
   aim of informing the sender's view on the transport state.  The state
   of a connection is dependent upon information based upon packet
   exchanges during the transport processes.  Firstly, there is
   information that is common to both client and server, such as the
   calculated round-trip time (RTT), although it may be measured using
   different packets at each end.  Secondly, there is state information
   that exists only at each endpoint, such as the size of the
   congestion, and receive windows.  Thus certain transport state
   information is only available at the server which can be useful to
   the client, for example, to calculate the current transport rate.
   This information may then be used to better inform a client of the
   state of the network path and make appropriate adaptations.