As required by RFC 4858, this is the current template for the Document
Changes are expected over time. 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?
Experimental - this is correctly indicated in the header. It is going as Experimental because there was not strong voice or reason for Standards Track, even though the WG charter permits it, and there are some issues for future research noted, though they are not believed to result in any unsafe conditions for the Internet.
(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:
Relevant content can frequently be found in the abstract
and/or introduction of the document. If not, this may be
an indication that there are deficiencies in the abstract
This document describes a general framework called CoDel (Controlled
Delay) that controls bufferbloat-generated excess delay in modern
networking environments. CoDel consists of an estimator, a setpoint,
and a control loop. It requires no configuration in normal Internet
deployments. CoDel comprises some major technical innovations and
has been made available as open source so that the framework can be
applied by the community to a range of problems. It has been
implemented in Linux (and available in the Linux distribution) and
deployed in some networks at the consumer edge. In addition, the
framework has been successfully applied in other ways.
Working Group Summary
Was there anything in WG process that is worth noting? For
example, was there controversy about particular points or
were there decisions where the consensus was particularly
CoDel was developed prior to the formation of the AQM working group. It was widely felt to be a good part of the answer to the "bufferbloat" problem that the IETF was trying to figure out how to deal with. The authors brought the specification of the algorithm to the working group after it was formed, and some clarifications and improvements to the description resulted from working group feedback.
Are there existing implementations of the protocol? Have a
significant number of vendors indicated their plan to
implement the specification? Are there any reviewers that
merit special mention as having done a thorough review,
e.g., one that resulted in important changes or a
conclusion that the document had no substantive issues? If
there was a MIB Doctor, Media Type or other expert review,
what was its course (briefly)? In the case of a Media Type
review, on what date was the request posted?
There are multiple existing implementations, in simulators (e.g. ns-2, ns-3) and real operating systems (e.g. Linux, FreeBSD). The quality of the document is high in terms of being able to write new implementations, as it contains significant amounts of pseudo-code to describe the algorithm, along with textual descriptions of its design facets.
Who is the Document Shepherd? Who is the Responsible Area
Wesley Eddy (firstname.lastname@example.org) is the document shepherd. Mirja Kuhlewind is the AD.
(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
I have reviewed the document multiple times and it is ready for publication.
(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?
(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
No additional special reviews are needed.
(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
No concerns or issues.
(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.
(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
There are no known IPR disclosures.
Note that there is dual-licensed BSD/GPLv2 code in the document.
(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?
WG consensus was strong to adopt and publish this document.
(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 https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
There are nits on references  and  that should be fixed in a later update (e.g. bundled with other fixes that result from IESG review).
Nits on RFC 896 and 2309 are spurious, as these are explicitly used as historic references. The nit on RFC 2581 can be bundled with other updates and made a reference to 5681.
(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.
(13) Have all references within this document been identified as
either normative or informative?
References are properly split into normative and informative sections. The RFC Editor may choose to handle the "URIs" reference section in some other way, if needed.
(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 procedure.
No downrefs are present, as this is an Experimental document.
(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.
No changes to other document status are made.
(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).
There are no required IANA actions.
(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.
(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.
None. There is C++-like pseudocode in the document. There are references to C code from the Linux kernel.