Skip to main content

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)?  

Standards Track.

> Why is this the proper type of RFC?  

Standards Track is apt because the document defines P2MP RSVP related 
formats and behaviors. [However, it is to be noted that the P2P version 
of this (RFC 4736) was published as an Informational document]

> 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

>   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.

Re-optimization of a Point-to-Multipoint (P2MP) Traffic Engineered
(TE) Label Switched Path (LSP) may be triggered based on the need to
re-optimize an individual source-to-leaf (S2L) sub-LSP or a set of
S2L sub-LSPs, both using Sub-Group-Based Re-optimization method, or
the entire P2MP-TE LSP tree using the Make-Before-Break (MBB) method.
Mechanisms that facilitate path re-optimization of loosely routed
Point-to-Point (P2P) TE LSPs include a method for the ingress node to
trigger a new path re-evaluation request and a method for the mid-
point node to notify availability of a preferred path.  This document
discusses the application of these mechanisms to the re-optimization
of loosely routed P2MP-TE LSPs, identifies issues in doing so and
proposes procedures to address them.

This document defines Resource Reservation Protocol (RSVP) signaling
extensions to allow the ingress node of a loosely routed P2MP-TE LSP
to request the re-evaluation of the LSP tree downstream of the node,
and a mid-point node to notify to the ingress node that a preferable
tree for the P2MP-TE LSP exists.  For re-optimizing a group of S2L
sub-LSPs in a tree using the Sub-Group-Based Re-optimization method,
an S2L sub-LSP descriptor list can be used to signal one or more S2L
sub-LSPs in an RSVP message.  This RSVP message may need to be
semantically fragmented when large number of S2L sub-LSPs are added
to the descriptor list.  This document introduces the notion of a
fragment identifier to help recipient nodes unambiguously reconstruct
the fragmented S2L sub-LSP descriptor list.

> 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?

This document moved from the CCAMP WG to TEAS WG as part of the 
routing WG changes. There was some serious debate regarding the 
introduction of fragment-identifier for S2L sub-LSP Descriptor. 
All concerns raised in regard to this have been addressed by the 

> 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?

The base GMPLS signaling protocol has been implemented. The procedures
discussed in this document are compatible with earlier implementations.
The Acknowledgements section of the draft does hint at the existence of
at least of one implementation. There have been no other public 
statements on implementation.

> Personnel
>  Who is the Document Shepherd? 

Vishnu Pavan Beeram

> Who is the Responsible Area Director?

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 Shepherd has reviewed the document as it has progressed 
through the WG (first CCAMP, then TEAS). The Shepherd believes this 
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?


> (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.


> (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.

No specific 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, see thread -

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

Yes, a couple of IPR disclosures have been filed that reference this
document (see and There was no WG discussion
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?   

Solid among those who are interested. "strong concurrence of a few
individuals, with others being silent" is a reasonable

> (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 extreme discontent seen.

> (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.

The document passes all ID nits except for one. The following error is
listed by the idnits tool:
** Downref: Normative reference to an Informational RFC: RFC 4736

> (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 (see RFC 3967)?
> If so, list these downward references to support the Area Director in 
> the Last Call procedure. 

Yes. There is one downward normative reference to an Informational RFC 
(RFC 4736) referenced in this document.

> (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).

The IANA section was fully reviewed by the document shepherd. All protocol 
extensions that the document makes are associated with the appropriate 
reservations in IANA registries.

> (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.