Shepherd writeup

As required by RFC 4858, this is the current template for the Document Shepherd Write-Up.

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)? 

Best Current Practise (BCP)

Why is this the proper type of RFC? 

The document supercedes the earlier BCP RFC2309, which made the case for using 
AQM to alleviate network collapse, and strongly suggested the "RED" would be the 
appropriate mechanism. However, due to numerous operational issues with RED, 
this new document is no longer pitching one particular method, and also the 
reason for having AQM has changed in focus over the years.

The original document (RFC2309) was produced by the IRTF. We did ask the IRTF 
if there is any issue to update their document and we got the feedback that the 
IETF should go ahead. This has been clarified between the AQM chairs, the IRTF 
chair, the IRSG, and the TSV ADs.

Is this type of RFC indicated in the title page header?


(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 document is a complete rework of the recommendations to have some form of 
active queue management in ideally every queue. While RFC2309 (1998) was mostly 
concerned around network stability, and made recommendations which did not 
appeal to operators (universal deployment of RED, which has been found to be 
particularly hard to configure correctly), this revised document includes the 
lessons learned over the past years. Also, the main focus is on reducing network 
latency, while still delivering improvements to network stability. It contains
a number of requirements, that a modern AQM mechanism should fulfill, without
endorsing one specific method.

Working Group Summary:

There was consensus early on about the aim and technical content of this 
document. However, specific wording (e.g. carrying over text from RFC2309, as 
this document started off as a 2309bis draft) was objected to.

Also, the question if this document should update or obsolete the earlier BCP 
(which was the result of discussions on the end2end mailing list, prior of 
formation of the IRTF) has been disussed eagerly.

On the technical grounds to argue for obsoleting the earlier BCP, this document 
specifically deprecates RED in favor of one of potentially several more modern 
AQM algorithms. Further, a point has been made that since it is not necessary to 
read RFC2309 to arrive at a sound understanding of the IETF (WG) consensus 
position around AQM, and the deviation is large enough with little overlap, having 
this document update 2309 was deemed less appropriate than obsoleting it.

Finally, one active participant has expressed very strong objections to some of 
the points summarized above, but later commented that he will accept his 
position as "in the rough". So, even though this was voiced at one point in 
time, an appeal is not expected.

Document Quality:

Are there existing implementations of the protocol? 

As a BCP, a number of operators and developers are following up on the updated 
recommendations. Newer mechanisms that fulfill the updated requirements have 
been developed by multiple parties and are already being deployed by third 
parties (e.g. DOCSIS PIE in Cable Modems). 

Have a significant number of vendors indicated their plan to implement the 

Yes; As a recommendation, it provides the necessary guidance when mechanisms are 
developed. Also, interoperability between AQMs is not as strict as in other 
areas, as many variants can be deployed along a path, as long as some over-
arching design principles are adhered to.

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? 

John Leslie and Bob Briscoe made comments that improved the overall document 
text, to align with the technical aim. However, these changes did not modify the 
technical content.


Who is the Document Shepherd? 

Richard Scheffenegger, AQM WG co-chair

Who is the Responsible Area Director?

Martin Stiemerling, Transport 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 the IESG.

The document had thorough discussions in the WG sessions. Both technical and 
wording have been honed, as witnessed also by the sheperd. There are no unresolved
issues which would preclude this from being forwarded to the IESG.

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

No; some discussions lately deviated from the document itself, and were rather 
procedural in content (e.g. update / obsolete / new BCP).

(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.

No; However, the document touches work that is done in other standards bodies 
such as IEEE, CableLabs, WFA, 3GPP, ITU. Participants in those organisations 
were part of the discussions and active feedback was also provided (e.g. DOCSIS-

(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 

A substancial part of the document was updated during WGLC on the insistence of 
one WG member; As they don't touch the main content, review of these sections 
(2-4) by the WG has been more limited.

(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 disclosures.


(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?

There is strong concensus on the document, with very few individuals disagreeing 
with some of the text. However, that disagreement does not appear to be about 
the technical parts. [[Check for -07]]

(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.)

This point has been discussed in confidence with the responsible AD. 

(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.

No idnits issues, that weren't also discussed in the WG (RFC2309 update wording 
in the abstact), with the current version what the WG has found to be most 

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

No formal reviews necessary.

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

Yes, all references are accounted for, and are split in normative and 
informative, as appropriate.

(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 no downref references at the time of this writeup.

(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.

Yes; former BCP RFC2309 will be obsoleted, as the guidance given herein is 
complete and self-contained.

(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).

No IANA actions required, no protocol updates are part of the document.

(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.

This RFC does not have any sections containing formal language, thus this is
not applicable.