The Some Congestion Experienced ECN Codepoint
draft-morton-tsvwg-sce-02
Transport Working Group J. Morton
Internet-Draft
Updates: 3168, 8311 (if approved) P. Heist
Intended status: Experimental
Expires: 6 May 2021 R.W. Grimes, Ed.
2 November 2020
The Some Congestion Experienced ECN Codepoint
draft-morton-tsvwg-sce-02
Abstract
This memo reclassifies ECT(1) to be an early notification of
congestion on ECT(0) marked packets, which can be used by AQM
algorithms and transports as an earlier signal of congestion than CE.
It is a simple, transparent, and backward compatible upgrade to
existing IETF-approved AQMs, RFC3168, and nearly all congestion
control algorithms.
Status of This Memo
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This Internet-Draft will expire on 6 May 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
Morton, et al. Expires 6 May 2021 [Page 1]
Internet-Draft sceb November 2020
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Some Congestion Experienced . . . . . . . . . . . . . . . . . 5
5. Design Rationale . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Risks with ECN Signaling . . . . . . . . . . . . . . . . 7
5.2. Unresponsive Flows . . . . . . . . . . . . . . . . . . . 8
5.3. Fairness . . . . . . . . . . . . . . . . . . . . . . . . 9
5.4. ECT(1) as SCE . . . . . . . . . . . . . . . . . . . . . . 9
6. Diffserv Usage . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. SCE Diffserv Codepoints (DSCPs) . . . . . . . . . . . . . 10
6.1.1. SCE-CAPABLE . . . . . . . . . . . . . . . . . . . . . 10
6.1.2. SCE-LOWDELAY . . . . . . . . . . . . . . . . . . . . 11
6.1.3. SCE-LOWCOST . . . . . . . . . . . . . . . . . . . . . 11
6.2. Diffserv Codepoints for Experimental and Private Use . . 11
6.3. Diffserv Codepoints for Public Use . . . . . . . . . . . 12
7. Examples of use . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Codel-type AQMs . . . . . . . . . . . . . . . . . . . . . 12
7.2. RED-type AQMs (including PIE) . . . . . . . . . . . . . . 13
7.3. Simple Two-Queue Middleboxes . . . . . . . . . . . . . . 13
7.4. TCP . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.5. Other . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Existing ECN & AQM Deployments . . . . . . . . . . . . . 14
8.2. L4S . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9. Ongoing Research and Development . . . . . . . . . . . . . . 16
10. Related Work . . . . . . . . . . . . . . . . . . . . . . . . 16
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
12. Security Considerations . . . . . . . . . . . . . . . . . . . 17
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
14. Normative References . . . . . . . . . . . . . . . . . . . . 17
15. Informative References . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
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