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)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

   The requested status is Proposed Standard. The Document is a protocol
   specification which requires the assignment of code points by the IANA, from a
   "Standards Action" registry. This justifies the type of RFC being requested.

(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

   An IP Multicast Distribution Tree (MDT) may traverse both label
   switching (i.e. - Multi-Protocol Label Switching, or MPLS) and non-
   label switching regions of a network.  Typically the MDT begins and
   ends in non-MPLS regions, but travels through an MPLS region.  In
   such cases, it can be useful to begin building the MDT as a pure IP
   MDT, then convert it to an MPLS Multipoint Label Switched Path (MP-
   LSP) when it enters an MPLS-enabled region, and then convert it back
   to a pure IP MDT when it enters a non-MPLS-enabled region.  Other
   documents specify the procedures for building such a hybrid MDT,
   using Protocol Independent Multicast (PIM) in the non-MPLS region of
   the network, and using Multipoint Extensions to Label Distribution
   Protocol (mLDP) in the MPLS region.  This document extends those
   procedures to handle the case where the link connecting the two
   regions is a "Virtual Routing and Forwarding Table" (VRF) link, as
   defined in the "BGP IP/MPLS VPN" specifications.  However, this
   document is primarily aimed at particular use cases where VRFs are
   used to support multicast applications other than Multicast VPN.

Working Group Summary

   The WG supports this Document and its progress.

Document Quality

   Two implementations of this protocol specification are known.
   The Document has been reviewed by experts and these experts are acknowledged
   in the appropriate section of the Document.


   Martin Vigoureux (L3VPN co-chair) is the Document Shepherd
   Stewart Bryant is the Responsible Area Director

(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 Shepherd has reviewed the recent revisions of this document and
   the last version as well. The Document is ready for publication.

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

   no concern. The Document has been thoroughly reviewed as part of a Routing
   Directorate review.

(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 specific additional review is 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
concerns here.

   There is no specific issue or concern with this Document.

(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, all authors have confirmed that they are not aware of any undisclosed IPR
   that applies to this Document.

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

   Yes, an IPR disclosure exists:
   The formal disclosure came a little bit late in the process (at the time of WG Last
   Call). However, the lead author had notified the Working Group (at the time of
   adoption by the Working Group) that an existing IPR disclosure (on another draft)
   was also applicable to this Document. This information has been reminded to the
   group within the WG Last Call e-mail. Satisfactory explanations were also given
   regarding why the appropriate disclosure took time. The Working Group was given
   the opportunity to speak with regards to the "late" disclosure. No concern has
   been raised.

(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 consensus is solid.   

(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.)

   No such extreme position/situation exists for that Document.

(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

   The result of the thorough nits check is clean.

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

   No formal review criteria needed.

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

   Yes. The references are appropriately categorized.

(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. All Normative references are in RFC status.

(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 downward reference.

(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.

   This Document does not change the status of existing RFCs. However as per the
   Document, it "extends the procedures from RFC6826 to handle the case where the
   link connecting the two regions is a "Virtual Routing and Forwarding Table" (VRF)
   link, as defined in the "BGP IP/MPLS VPN" specifications [RFC6513].", but no
   changes are brought to RFC6826.

(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).

   The Document requests the IANA to assign 4 new code-points from an existing
   registry (LDP MP Opaque Value Element basic type), defined by RFC 6388 and for
   which the registration procedure is by Standards Action.
   Out of these 4 new code points the Documents kindly asks the IANA to assign two
   specific values (250 for the Transit VPNv4 Source TLV and 251 for the Transit
   VPNv6 Source TLV). These values are strongly suggested as they are already part
   of an existing implementation. An early allocation procedure should have been
   followed in such a situation. It has not been the case. The WG co-Chairs have
   decided that initiating the procedure when the document is ready for publication
   would not bring a lot of benefits, thus the maintained direct request in the

(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 registry is required and thus no expert review needed.

(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.

   no such section in the Document.