Shepherd writeup

Document Writeup for Working Group Documents

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?

Informational. This document isn't defining a new protocol, but rather methods to optimize the use of PIM-based multicast in a VPLS environment. The type of RFC is indicated on the title page.

(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 describes the procedures and recommendations for
   Virtual Private LAN Service (VPLS) Provider Edges (PEs) to facilitate
   replication of multicast traffic to only certain ports (behind which
   there are interested Protocol Independent Multicast (PIM) routers
   and/or Internet Group Management Protocol (IGMP) hosts) via Protocol
   Independent Multicast (PIM) snooping and proxying.

Working Group Summary:

The primary thing to note about the WG process was the length of time it's taken to get this done. This is primarily due to two factors. The first is that it started in the L2VPN WG, and there was a five-year gap between draft-ietf-l2vpn-vpls-pim-snooping revisions -01 and -02. My understanding is that was due to the implementors both gaining experience with deployed code at that time, and not having the time to get back to the draft. Once the work restarted in L2VPN, there was a last call, however, due to review comments, work continued on the draft. When the PWE3 and L2VPN WGs were merged into the PALS WG, it was reissued as a PALS draft, and updates continued from additional experience from the field and some fresh sets of eyes.

Document Quality:

The document has existed in one form or another since 2005, and has gone through a total of 15 revisions. It has been though WG last call twice (see above for the WG history). There is at least one known implementation that has been deployed in the field for a number of years.


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

Andy Malis. Deborah Brungard.

(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 has been reviewed and is ready for publication. There is one nit to be corrected, but that can be done by the RFC Editor if there are no other changes needed (see below).

(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.,
, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.


(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.

This is not a concern, just an observation. The Security Considerations section is light, but that is because this document is Informational and doesn't define any new protocols. The section does refer back to the Security Considerations in the base VPLS documents, since they would also apply to this document. The described methods to optimize the use of PIM-based multicast in a VPLS environment do not introduce any new security concerns.

(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. In addition to the current set of authors, the PALS document shepherd also polled the authors of previous L2VPN and individual revisions of the document, and received affirmative replies from all of them. In some cases, it was fortuitous that the old email addresses still worked.

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

There is one IPR declaration that was issued when it was still an L2VPN WG document. There have not been any concerns expressed by either the L2VPN or PALS WGs.

(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?

It represents the combined work of a number of authors though the years from almost as many different organizations. There have been comments over the years that have been incorporated into the text, and there are no objections to this being published.

(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 thorough.

There are two minor nits noted by the tool. The only real one is an outdated RFC reference that can be corrected by the RFC Editor if no other changes are required prior to publication, RFC 4601 was obsoleted by RFC 7761. Note that Section 2.3.3 of this draft discusses how the draft explicitly doesn't address the major feature of RFC 4601 that was removed by RFC 7761, "(*,*,RP)" support.

The other reported nit isn't real. The tool thought that it detected embedded code, but it's just pseudocode used to express forwarding rules.

(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?


(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).

There are no IANA considerations.

(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.