Multipath Extension for QUIC

Document Type Active Internet-Draft (individual)
Authors Yanmei Liu  , Yunfei Ma  , Christian Huitema  , Qing An  , Zhenyu Li 
Last updated 2020-12-15
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QUIC                                                              Y. Liu
Internet-Draft                                                     Y. Ma
Intended status: Standards Track                            Alibaba Inc.
Expires: 19 June 2021                                         C. Huitema
                                                    Private Octopus Inc.
                                                                   Q. An
                                                            Alibaba Inc.
                                                                   Z. Li
                                                        16 December 2020

                      Multipath Extension for QUIC


   This document specifies multipath extension for the QUIC protocol to
   enable the simultaneous usage of multiple paths for a single
   connection.  The extension is compliant with the single-path QUIC
   design.  The design principle is to support multipath by adding
   limited extension to [QUIC-TRANSPORT].

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   This Internet-Draft will expire on 19 June 2021.

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Table of Contents

   1.  Introduction
   2.  Conventions and Definitions
   3.  Enable Multipath QUIC - Handshake
   4.  Path Management
     4.1.  Path Identifier and Connection ID
     4.2.  Path Packet Number Spaces
     4.3.  Path Initiation
     4.4.  Path State Management
     4.5.  Path Close
       4.5.1.  Use PATH_STATUS frame to close a path
       4.5.2.  Use RETIRE_CONNECTION_ID frame to close a path
       4.5.3.  Idle timeout
   5.  Using TLS to Secure QUIC Multipath
     5.1.  Packet protection for QUIC Multipath
     5.2.  Key Update for QUIC Multipath
   6.  Using Multipath QUIC with load balancers
   7.  Packet scheduling
     7.1.  Basic Scheduling
     7.2.  Scheduling with QoE Feedback
     7.3.  Per-stream Policy
   8.  Congestion control and loss detection
     8.1.  Congestion control
     8.2.  Packet number space and acknowledgements
     8.3.  Flow control
   9.  New frames
     9.1.  PATH_STATUS frame
     9.2.  ACK_MP frame
     9.3.  QOE_CONTROL_SIGNALS frame
   10. Security Considerations
   11. IANA Considerations
   12. Changelog
   13. Appendix.A Scenarios related to migration
   14. Appendix.B Considerations on RTT estimate and loss detection
   15. Appendix.C Difference from past proposals
   16. References
     16.1.  Normative References
     16.2.  Informative References
   Authors' Addresses

1.  Introduction

   In this document, we propose an extension to the current QUIC design
   to enable the simultaneous usage of multiple paths for a single

   This proposal is based on several basic design points:

   *  Re-use as much as possible mechanisms of QUIC-v1, which has
      supported connection migration and path validation.

   *  To avoid the risk of packets being dropped by middleboxes (which
      may only support QUIC-v1), use the same packet header formats as
      QUIC V1.

   *  Endpoints need a Path Identifier for each different path which is
      used to track states of packets.  As we want to keep the packet
      header formats unchanged [QUIC-TRANSPORT], Connection IDs (and the
      sequence number of Connection IDs) would be a good choice of Path

   *  For the convenience of packet loss detection and recovery,
      endpoints use a different packet number space for each Path

   *  Congestion Control, RTT measurements and PMTU discovery should be
      per-path (following [QUIC-TRANSPORT])
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