Baseline Encoding and Transport of Pre-Congestion Information
RFC 5696
Document | Type |
RFC - Proposed Standard
(November 2009; Errata)
Obsoleted by RFC 6660
|
|
---|---|---|---|
Authors | Bob Briscoe , T Moncaster , Michael Menth | ||
Last updated | 2015-10-14 | ||
Replaces | draft-moncaster-pcn-baseline-encoding | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
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 (http://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 BSD License. Moncaster, et al. Standards Track [Page 1] RFC 5696 Baseline PCN Encoding November 2009 This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. 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 Appendix B. Co-Existence of PCN and ECN (Informative) . . . . . . 13 Moncaster, et al. Standards Track [Page 2]Show full document text