Shepherd writeup

Changes are expected over time. This version is dated 6 June 2019.

(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


The type of RFC is not indicated in the title page header, but is referred
to in the Introduction.

BCP is the appropriate type for this RFC as it provides guidance for
deprecating ASM and using only SSM for interdomain multicast.

(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:

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 or introduction.

This document recommends a BCP for deprecation and replacement of
Any-Source Multicast (ASM) methods for interdomain multicast with
Source-Specific Multicast (SSM). This document additionally recommends
host/network support for Internet Group Messaging Protocol version 3
(IGMPv3) and Multicast Listener Discovery version 2 (MLDv2). Further
guidance for these protocols can be found in [ RFC4604 ].

Scale limitations of the commonly used Sparse-Mode (PIM-SM)/Multicast
Source Discovery Protocol (MSDP) ASM architecture are appropriately
highlighted as the premise for this recommendation. Design comparisons,
highlighting practical and operational improvements using an SSM-based
interdomain multicast design are appropriate and informative.

This document makes no recommendations for intradomain multicast.

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 rough?

There was some initial concern from a few individuals that ASM was still
useful in intradomain deployments.  The authors resolved these concerns by
making it clear throughout the doc that this recommendation to deprecate
ASM applies only to interdomain deployments and makes no recommendations
for intradomain multicast deployments.  Other than this, no other
controversies with this document were noted.


Document Quality:

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?

Document is well written, defining a clear problem statement and
supporting scenarios and examples for the core recommendations.
Assumptions regarding the future-state of ASM protocols are appropriately
highlighted, and the impact on the document recommendations are addressed.


Who is the Document Shepherd? Who is the Responsible Area Director?


  Document shepherd: Colin Doyle
  Responsible AD: Warren Kumari


(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

I have read the draft and reviewed the minutes and etherpad records for
the mboned WG. This draft is supported by participants and

(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 took

No. Recommendations defined are appropriate and supported. Future
adjustments to these recommendations based on protocol and standards
development are accounted for.

(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.
I have no concerns that warrant review, although I would expect the usual
slow adoption cycle of the protocols required by the recommendations in
this document by providers and, to a lesser extent, manufacturers. This
document posits that support for these protocols (IGMPv3 and MLDv2) is
"widespread" in common OS's. This is an optimistic supposition that
naturally assumes that devices running common OS's are running current
versions. As this document lays out no specific timeline for deprecating
multidomain ASM, this consideration becomes largely academic.

(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?

Each author has confirmed that he is not aware of any IPR:

No IPR disclosures from anyone else in the WG were noted.


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

Each author has confirmed that he is not aware of any IPR.  No IPR
disclosures from anyone else in the WG were noted.


(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?
Consensus is strong. Areas of discussion were found to be largely around
the scope and forcefulness of the recommendation as it related to
intradomain multicast. Ultimately, the language recommending deprecation
of ASM for intradomain multicast were removed.

"I think it's important that we don't water down the recommendation so
much that the message gets lost.  My pref would be to strongly recommend
SSM (and thus, no-ASM) for interdomain and provide some gentle nudging for
SSM in intradomain, while recognizing that what one does in his own
network is his own business.  We can't really mandate/decree, but it is
our role/responsibility to provide guidance and recommendations based on
our expertise." - Tim Chown

(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
Nits check was run against version 5 of this draft.
Nit regarding multicast addresses can be disregarded as document is
referencing the complete multicast ipv4 range and not a generic example
multicast address.
Nit regarding age of document is assumed trivial and disregarded. Version
reviewed is current.
Nit regarding draft publication should result in an edit/update. On line
377, 705, and 707, draft-ietf-6man-rfc6434-bis is referenced. This draft
has been published as RFC8504.

(12) Describe how the document meets any required formal review criteria,
such as the MIB Doctor, media type, and URI type reviews.
No review 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?
No, but an edit to the document is required. All references are currently
in RFC status. The reference to "I-D.ietf-6man-rfc6434-bis" should be
updated to reflect the published RFC8504.

(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.
None based on my review.

(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. This document provides BCP recommendations using existing protocols,
standards, and RFC's.

(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 8126).
No request of IANA are made or required by this document per section 7.

(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.
No new IANA registries are required by this document per section 7.

(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.