Multipath Extension for QUIC
QUIC Y. Liu
Internet-Draft Y. Ma
Intended status: Standards Track Alibaba Inc.
Expires: 19 June 2021 C. Huitema
Private Octopus Inc.
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].
Status of This Memo
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This Internet-Draft will expire on 19 June 2021.
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Table of Contents
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
13. Appendix.A Scenarios related to migration
14. Appendix.B Considerations on RTT estimate and loss detection
15. Appendix.C Difference from past proposals
16.1. Normative References
16.2. Informative References
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
* 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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