Shepherd writeup

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. The draft proposes a new algorithm for lower than best-effort
transport and requires further experimentation and targeted deployments before
it is ready for standards track.

(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 describes an experimental congestion algorithm for building a
lower than best-effort transport. The algorithm attempts to use the residual
capacity on an end-to-end path while limiting queuing delay. The algorithm sense
increase in one-way delay measurements to yield in the presence of any competing
flows thus limiting interference with the network performance of competing

Working Group Summary

We reached consensus on the basic algorithm a long while back while most of the
later revisions and discussions were around parameterization and choosing the
right defaults. This is expected as this is an experimental algorithm and data
needs to guide these decisions rather than theory. In the end we got enough
(independent) experimental data that guided the design decisions.

Document Quality

There are several independent implementations including BitTorrent itself which
pioneered this algorithm and ship it in their product. A number of universities
and more recently Apple prototyped and shared results during the last call. I am
confident that parameterization
and associated tradeoffs are well understood and


Who is the Document Shepherd? Who is the Responsible Area

Murari Sridharan (<>) is the
Document Shepherd.
Wesley Eddy (<>)
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
the IESG.

I have been a co-chair right from the start and have reviewed this version and
all of the previous versions and believe the current version is ready for

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

No. The algorithm from the beginning has gone through thorough reviews
including the final version. The chairs also forwarded the document to ICCRG and
may folks from ICCRG are also part of the LEDBAT WG.

(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.

This document should be reviewed by both TCPM and ICCRG as there are broader
implications. Several folks who are part of LEDBAT are also part of these other
WG and I am also co-chair for ICCRG. The final version of the document has been
cross-posted to the relevant WGs. I therefore have no concerns here.

(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.

None. Key concerns have been captured in the doc.

(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 I believe so.

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


(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?

I believe the consensus is quite strong. Several people who are experts in the
area commented during the life time of the algorithm development and also
specifically during the last call. A document addressing these concerns was
posted back to the group and elicited no further comments.

(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

== Unused Reference: 'RFC6298' is defined on line 718, but no explicit
reference was found in the text
'[RFC6298] Paxson, V., Allman, M., Chu, J., and M. Sargent, "Computi...'

(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?

Yes. The following aren’t normative and should be moved to informative.

[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP",
RFC 3168<http:"" html="" rfc3168="">, September 2001.

[RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
Discovery", RFC 4821<http:"" html="" rfc4821="">, March 2007.

(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.

(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.


(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).

IANA section exists but no considerations required for this 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.