Baseline Encoding and Transport of Pre-Congestion Information
RFC 5696
| Document | Type |
RFC - Proposed Standard
(November 2009; Errata)
Obsoleted by RFC 6660
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Replaces | draft-moncaster-pcn-baseline-encoding | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5696 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Lars Eggert | ||
| Send notices to | (None) | ||
Network Working Group T. Moncaster
Request for Comments: 5696 B. Briscoe
Category: Standards Track BT
M. Menth
University of Wuerzburg
November 2009
Baseline Encoding and Transport of Pre-Congestion Information
Abstract
The objective of the Pre-Congestion Notification (PCN) architecture
is to protect the quality of service (QoS) of inelastic flows within
a Diffserv domain. It achieves this by marking packets belonging to
PCN-flows when the rate of traffic exceeds certain configured
thresholds on links in the domain. These marks can then be evaluated
to determine how close the domain is to being congested. This
document specifies how such marks are encoded into the IP header by
redefining the Explicit Congestion Notification (ECN) codepoints
within such domains. The baseline encoding described here provides
only two PCN encoding states: Not-marked and PCN-marked. Future
extensions to this encoding may be needed in order to provide more
than one level of marking severity.
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (c) 2009 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
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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 BSD License.
Moncaster, et al. Standards Track [Page 1]
RFC 5696 Baseline PCN Encoding November 2009
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3
3. Terminology and Abbreviations . . . . . . . . . . . . . . . . 3
3.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. List of Abbreviations . . . . . . . . . . . . . . . . . . 4
4. Encoding Two PCN States in IP . . . . . . . . . . . . . . . . 4
4.1. Marking Packets . . . . . . . . . . . . . . . . . . . . . 5
4.2. Valid and Invalid Codepoint Transitions . . . . . . . . . 6
4.3. Rationale for Encoding . . . . . . . . . . . . . . . . . . 7
4.4. PCN-Compatible Diffserv Codepoints . . . . . . . . . . . . 7
4.4.1. Co-Existence of PCN and Not-PCN Traffic . . . . . . . 8
5. Rules for Experimental Encoding Schemes . . . . . . . . . . . 8
6. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 10
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . . 10
10.2. Informative References . . . . . . . . . . . . . . . . . . 10
Appendix A. PCN Deployment Considerations (Informative) . . . . . 11
A.1. Choice of Suitable DSCPs . . . . . . . . . . . . . . . . . 11
A.2. Rationale for Using ECT(0) for Not-Marked . . . . . . . . 12
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