Subject: I-D Action:draft-briscoe-tsvwg-re-ecn-tcp-05.txt

From: [email-masked]
Date: Thu, 10 Jan 2008 08:40:02 -0500

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title           : Re-ECN: Adding Accountability for Causing Congestion to TCP/IP
	Author(s)       : B. Briscoe, et al.
	Filename        : draft-briscoe-tsvwg-re-ecn-tcp-05.txt
	Pages           : 89
	Date            : 2008-01-10

This document introduces a new protocol for explicit congestion
notification (ECN), termed re-ECN, which can be deployed
incrementally around unmodified routers.  The protocol arranges an
extended ECN field in each packet so that, as it crosses any
interface in an internetwork, it will carry a truthful prediction of
congestion on the remainder of its path.  Then the upstream party at
any trust boundary in the internetwork can be held responsible for
the congestion they cause, or allow to be caused.  So, networks can
introduce straightforward accountability and policing mechanisms for
incoming traffic from end-customers or from neighbouring network
domains.  The purpose of this document is to specify the re-ECN
protocol at the IP layer and to give guidelines on any consequent
changes required to transport protocols.  It includes the changes
required to TCP both as an example and as a specification.  It also
gives examples of mechanisms that can use the protocol to ensure data
sources respond correctly to congestion.  And it describes example
mechanisms that ensure the dominant selfish strategy of both network
domains and end-points will be to set the extended ECN field
honestly.

Authors' Statement: Status (to be removed by the RFC Editor)

Although the re-ECN protocol is intended to make a simple but far-
reaching change to the Internet architecture, the most immediate
priority for the authors is to delay any move of the ECN nonce to
Proposed Standard status.  The argument for this position is
developed in Appendix I.

Changes from previous drafts (to be removed by the RFC Editor)

Full diffs created using the rfcdiff tool are available at
<http://www.cs.ucl.ac.uk/staff/B.Briscoe/pubs.html#retcp>

>From -04 to -05 (current version):

Completed justification for packet marking with FNE during slow-

start(Appendix D).

Minor editorial changes throughout.

>From -03 to -04:

Clarified reasons for holding back ECN nonce (Section 3.2 &

Appendix I).

Clarified Figure 1.

Added Section 4.1.1.1 on equivalence of drops and ECN marks.

Improved precision of Section 5.6 on IP in IP tunnels.

Explained the RTT fairness is possible to enforce, but unlikely to

be required (Section 6.1.3 & Appendix F).

Explained that bulk per-user policing should be adequate but per-

flow policing is also possible if desired, though it is not likely

to be necessary (Section 6.1.5 & Appendix G).

Reinforced need for passive policing at inter-domain borders to

enable all-optical networking (Section 6.1.6).

Minor editorial changes throughout.

>From -02 to -03:

Started guidelines for re-ECN support in DCCP and SCTP.

Added annex on limitations of nonce mechanism.

Minor editorial changes throughout.

>From -01 to -02:

Explanation on informal terminology in Section 3.4 clarified.

IPv6 wire protocol encoding added (Section 5.2).

Text on (non-)issues with tunnels, encryption and link layer

congestion notification added (Section 5.6 & Section 5.7).

Section added giving evolvability arguments against encouraging

bottleneck policing (Section 6.1.2).  And text on re-ECN's

evolvability by design added to Section 6.1.3

Text on inter-domain policing (Section 6.1.6) and inter-domain

fail-safes (Section 6.1.7) added.

>From -00 to -01:

Encoding of re-ECN wire protocol changed for reasons given in

Appendix B and consequently draft substantially re-written.

Substantial text added in sections on applications, incremental

deployment, architectural rationale and security considerations.

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http://www.ietf.org/internet-drafts/draft-briscoe-tsvwg-re-ecn-tcp-05.txt

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