Skip to main content

Shepherd writeup

Explicit Congestion Notification (ECN) Experimentation

As required by RFC 4858, this is the current template for the Document Shepherd
Write-Up. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet
Standard, Informational, Experimental, or Historic)? Why is this the proper
type of RFC? Is this type of RFC indicated in the title page header?

Standards Track, PS.

(2) The IESG approval announcement includes a Document Announcement Write-Up.
Please provide such a Document Announcement Write-Up. Recent examples can be
found in the "Action" announcements for approved documents. The approval
announcement contains the following sections:

Technical Summary:

   This memo updates RFC 3168, which specifies Explicit Congestion
   Notification (ECN) as a replacement for packet drops as indicators of
   network congestion.  It relaxes restrictions in RFC 3168 that would
   otherwise hinder experimentation towards benefits beyond just removal
   of loss.  The memo summarizes the anticipated areas of
   experimentation and updates RFC 3168 to enable experimentation in
   these areas.  An Experimental RFC is required to take advantage of
   any of these enabling updates.  In addition, this memo makes related
   updates to the ECN specifications for RTP in RFC 6679 and for DCCP in
   RFC 4341, RFC 4342 and RFC 5622.  The memo also records the
   conclusion of the ECN Nonce experiment in RFC 3540, and provides the
   rationale for reclassification of RFC 3540 as Historic; this
   reclassification enables new experimental use of the ECT(1)

Working Group Summary:

The document was adopted by the working group to enable two specific pieces of
work - ABE (now in TCPM) and L4S (now a working group item in TSVWG). Both
these items of work curently have experimental status, yet seek to modify the
ECN specification produced by TSVWG - specifically to obsolete the ECN NONCE.
This topic has been discussed in TSVWG over many years and it is finally the
consensus that the experiment has concluded and that the ECN NONCE
specification is no longer recommended for deployment.

Document Quality: The document is ready to publish.


Who is the Document Shepherd?  Gorry Fairhurst

Who is the Responsible Area Director? Spencer Dawkins

(3) Briefly describe the review of this document that was performed by the
Document Shepherd. If this version of the document is not ready for
publication, please explain why the document is being forwarded to the IESG.

The document has received significant review by several people in TSVWG - both
as an individual submission and as as WG draft, including detailed feedback
from M Welzl and B Briscoe. Minor updates were made in response to last call
comments and this document is therefore ready to proceed.

(4) Does the document Shepherd have any concerns about the depth or breadth of
the reviews that have been performed?

No. This draft has been reviewed many times.

(5) Do portions of the document need review from a particular or from broader
perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or
internationalization? If so, describe the review that took place.


(6) Describe any specific concerns or issues that the Document Shepherd has
with this document that the Responsible Area Director and/or the IESG should be
aware of? For example, perhaps he or she is uncomfortable with certain parts of
the document, or has concerns whether there really is a need for it. In any
event, if the WG has discussed those issues and has indicated that it still
wishes to advance the document, detail those concerns here.


(7) Has each author confirmed that any and all appropriate IPR disclosures
required for full conformance with the provisions of BCP 78 and BCP 79 have
already been filed. If not, explain why?

Yes. The author confirms that he knows of no IPR for this document.

(8) Has an IPR disclosure been filed that references this document? If so,
summarize any WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosures known.

(9) How solid is the WG consensus behind this document? Does it represent the
strong concurrence of a few individuals, with others being silent, or does the
WG as a whole understand and agree with it?

The document has been presented to the WG and there was consensus on the
document during WGLC. Minor issues were raised, and changes have been
incorporated in this revision of the ID.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent?
If so, please summarise the areas of conflict in separate email messages to the
Responsible Area Director. (It should be in a separate email because this
questionnaire is publicly available.)


(11) Identify any ID nits the Document Shepherd has found in this document.
(See and the Internet-Drafts Checklist).
Boilerplate checks are not enough; this check needs to be thorough.


(12) Describe how the document meets any required formal review criteria, such
as the MIB Doctor, media type, and URI type reviews.

Not required.

(13) Have all references within this document been identified as either
normative or informative?


(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative references
exist, what is the plan for their completion?


(15) Are there downward normative references references (see RFC 3967)? If so,
list these downward references to support the Area Director in the Last Call

There are two downrefs in this draft that is intended to become a proposed
status RFC: - This draft explains the end of the ECN Nonce experiment described
in RFC 3540, and hence normatively references RFC 3540. - DCCP sender ECN
behavior needs to be updated in 3 RFCs, one of which is Experimental - RFC 5622.

(16) Will publication of this document change the status of any existing RFCs?
Are those RFCs listed on the title page header, listed in the abstract, and
discussed in the introduction? If the RFCs are not listed in the Abstract and
Introduction, explain why, and point to the part of the document where the
relationship of this document to the other RFCs is discussed. If this
information is not in the document, explain why the WG considers it unnecessary.

After analysis of the deployment and purpose of ECM NONCE, this doc is the
supporting RFC for a change of RFC3540 (EXP) status to Historic.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes are
associated with the appropriate reservations in IANA registries. Confirm that
any referenced IANA registries have been clearly identified. Confirm that newly
created IANA registries include a detailed specification of the initial
contents for the registry, that allocations procedures for future registrations
are defined, and a reasonable name for the new registry has been suggested (see
RFC 5226). This memo does not make a request to IANA.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find useful in
selecting the IANA Experts for these new registries.

This memo does not include a request for a new registry to IANA.

(19) Describe reviews and automated checks performed by the Document Shepherd
to validate sections of the document written in a formal language, such as XML
code, BNF rules, MIB definitions, etc.