Multipath TCP Extension for Robust Session Establishment
draft-amend-tcpm-mptcp-robe-00

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Last updated 2020-07-07
Replaces draft-amend-mptcp-robe
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TCP Maintenance and Minor Extensions                            M. Amend
Internet-Draft                                                        DT
Intended status: Experimental                                    J. Kang
Expires: 8 January 2021                                           Huawei
                                                             7 July 2020

        Multipath TCP Extension for Robust Session Establishment
                     draft-amend-tcpm-mptcp-robe-00

Abstract

   Multipath TCP extends the plain, single-path limited, TCP towards the
   capability of multipath transmission.  This greatly improves the
   reliability and performance of TCP communication.  For backwards
   compatibility reasons the Multipath TCP was designed to setup
   successfully an initial path first, after which subsequent paths can
   be added for multipath transmission.  For that reason the Multipath
   TCP has the same limitations as the plain TCP during connection
   setup, in case the selected path is not functional.

   This document proposes a set of implementations and possible
   combinations thereof, that provide a more Robust Establishment (RobE)
   of MPTCP sessions.  It includes RobE_TIMER, RobE_SIM, RobE_eSIM and
   RobE_IPS.

   RobE_TIMER is designed to stay close to MPTCP in that standard
   functionality is used wherever possible.  Resiliency against network
   outages is achieved by modifying the SYN retransmission timer: If one
   path is defective, another path is used.

   RobE_SIM and RobE_eSIM provides the ability to simultaneously use
   multiple paths for connection setup.  They ensure connectivity if at
   least one functional path out of a bunch of paths is given and offers
   beside that the opportunity to significantly improve loading times of
   Internet services.

   RobE_IPS provides a heuristic to select properly an initial path for
   connection establishment with a remote host based on empirical data
   derived from previous connection information.

   In practice, these independent solutions can be complementary used.
   This document also presents the design and protocol procedure for
   those combinations in addition to the respective stand-alone
   solutions.

Amend & Kang             Expires 8 January 2021                 [Page 1]
Internet-Draft                 MPTCP RobE                      July 2020

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on 8 January 2021.

Copyright Notice

   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 (https://trustee.ietf.org/
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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   6
   2.  Implementation without MPTCP protocol adaptation  . . . . . .   7
     2.1.  Re-transmission Timer(RobE_TIMER) . . . . . . . . . . . .   7
     2.2.  Simultaneous Initial Paths Simple Version (RobE_SIM)  . .   8
     2.3.  Heuristic Initial Path Selection (RobE_IPS) . . . . . . .   9
       2.3.1.  Architecture  . . . . . . . . . . . . . . . . . . . .   9
       2.3.2.  Typical Scenarios . . . . . . . . . . . . . . . . . .  10
       2.3.3.  Path decision information . . . . . . . . . . . . . .  13
       2.3.4.  Initial Path Selection use local RTT information  . .  14
     2.4.  Combination of RobE_SIM and RobE_IPS  . . . . . . . . . .  14
     2.5.  Combination of RobE_TIMER and RobE_IPS  . . . . . . . . .  15
   3.  Implementation with Bi-directional MPTCP Support  . . . . . .  16
     3.1.  Simultaneous Initial Paths Extended Version
           (RobE_eSIM) . . . . . . . . . . . . . . . . . . . . . . .  17

Amend & Kang             Expires 8 January 2021                 [Page 2]
Internet-Draft                 MPTCP RobE                      July 2020
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