TCP Extensions for Multipath Operation with Multiple Addresses
RFC 8684
| Document | Type |
RFC - Proposed Standard
(March 2020; No errata)
Obsoletes RFC 6824
|
|
|---|---|---|---|
| Authors | Alan Ford , Costin Raiciu , Mark Handley , Olivier Bonaventure , Christoph Paasch | ||
| Last updated | 2020-03-30 | ||
| Replaces | draft-bonaventure-mptcp-exp-option | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml pdf htmlized (tools) htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Philip Eardley | ||
| Shepherd write-up | Show (last changed 2019-05-09) | ||
| IESG | IESG state | RFC 8684 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Mirja Kühlewind | ||
| Send notices to | Philip Eardley <philip.eardley@bt.com> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) A. Ford
Request for Comments: 8684 Pexip
Obsoletes: 6824 C. Raiciu
Category: Standards Track U. Politehnica of Bucharest
ISSN: 2070-1721 M. Handley
U. College London
O. Bonaventure
U. catholique de Louvain
C. Paasch
Apple, Inc.
March 2020
TCP Extensions for Multipath Operation with Multiple Addresses
Abstract
TCP/IP communication is currently restricted to a single path per
connection, yet multiple paths often exist between peers. The
simultaneous use of these multiple paths for a TCP/IP session would
improve resource usage within the network and thus improve user
experience through higher throughput and improved resilience to
network failure.
Multipath TCP provides the ability to simultaneously use multiple
paths between peers. This document presents a set of extensions to
traditional TCP to support multipath operation. The protocol offers
the same type of service to applications as TCP (i.e., a reliable
bytestream), and it provides the components necessary to establish
and use multiple TCP flows across potentially disjoint paths.
This document specifies v1 of Multipath TCP, obsoleting v0 as
specified in RFC 6824, through clarifications and modifications
primarily driven by deployment experience.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8684.
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/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
1.1. Design Assumptions
1.2. Multipath TCP in the Networking Stack
1.3. Terminology
1.4. MPTCP Concept
1.5. Requirements Language
2. Operation Overview
2.1. Initiating an MPTCP Connection
2.2. Associating a New Subflow with an Existing MPTCP Connection
2.3. Informing the Other Host about Another Potential Address
2.4. Data Transfer Using MPTCP
2.5. Requesting a Change in a Path's Priority
2.6. Closing an MPTCP Connection
2.7. Notable Features
3. MPTCP Operations: An Overview
3.1. Connection Initiation
3.2. Starting a New Subflow
3.3. MPTCP Operation and Data Transfer
3.3.1. Data Sequence Mapping
3.3.2. Data Acknowledgments
3.3.3. Closing a Connection
3.3.4. Receiver Considerations
3.3.5. Sender Considerations
3.3.6. Reliability and Retransmissions
3.3.7. Congestion Control Considerations
3.3.8. Subflow Policy
3.4. Address Knowledge Exchange (Path Management)
3.4.1. Address Advertisement
3.4.2. Remove Address
3.5. Fast Close
3.6. Subflow Reset
3.7. Fallback
3.8. Error Handling
3.9. Heuristics
3.9.1. Port Usage
3.9.2. Delayed Subflow Start and Subflow Symmetry
3.9.3. Failure Handling
4. Semantic Issues
5. Security Considerations
6. Interactions with Middleboxes
7. IANA Considerations
7.1. TCP Option Kind Numbers
7.2. MPTCP Option Subtypes
7.3. MPTCP Handshake Algorithms
7.4. MP_TCPRST Reason Codes
8. References
8.1. Normative References
8.2. Informative References
Appendix A. Notes on Use of TCP Options
Appendix B. TCP Fast Open and MPTCP
B.1. TFO Cookie Request with MPTCP
B.2. Data Sequence Mapping under TFO
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