Shepherd writeup

Template date:  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?

Proposed Standard 

(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 defines a way for a Border Gateway Protocol Link-State
   (BGP-LS) speaker to advertise multiple types of supported Maximum SID
   Depths (MSDs) at node and/or link granularity.

   Such advertisements allow entities (e.g., centralized controllers) to
   determine whether a particular Segment Identifier (SID) stack can be
   supported in a given network.

Working Group Summary

  Was there anything in WG process that is worth noting?
   2 IPR filed on this work
   2 implementation are only cisco 

WG LC is at:

   For example, was there controversy about particular points or 
  were there decisions where the consensus was particularly 
  rough?   WG consensus was postive with indications of 
 that this feature was needed in BGP-LS neworks. 

Document Quality

  Are there existing implementations of the protocol? 
    2 Cisco implementations have indicated support for the protocol. 
    see report at:    

   Have a  significant number of vendors indicated their plan to 
  implement the specification? 
  Additional vendors with segment routing implementations 
  have indicated they which to add the MSD feature.  
      No additional vendors indicated a plan to implement the IDR MSD feature. 
      However, there is support for this feature in SR in the LSR  WG. 

  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? 
     RTG-DIR: Mach Chen 

  If  there was a MIB Doctor, Media Type or other expert review, 
  what was its course (briefly)?  
  OPS-DIR early review requested: pending

  Who is the Document Shepherd?  Susan Hares
  Who is the Responsible AD? Alvaro Retana 
   RTG-DIR early review:   Mach Chen 

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  

1. NITS run  on each version. 
2. Review of entire document and dependents
  (-04.txt, -05.txt, -06.txt, -07.txt, -08.txt) 

Current text in shepherd: 
The document lacks error handling section that indicates
what happens if the TLVS are incorrectly parsed.  
Needs draft-ietf-idr-rfc7752bis-00 reference and clarified 
management based on yang models.   

3.  RTG-DIR QA:  Mach Chen
Ready.   Minor nits he mentioned addressed in -08.txt 

If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

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

No.   The WG has been asked about 

(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 is a normal SR draft so the following suggestions are made for the reviewers: 

RTG-DIR Review should look LSR documents linked. 
OPS-DIR review should look at operational support of the SR function. 

To this shepherd, MSD seems to improve the manageability of the 
SR functions in a network. 

(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.

RFC7752 is being revised by IDR to clarify sections in the draft 
based on implementation experience.   Rushing RFC7752bis to 
completion is unwise since it takes careful review of the implementation 
reports to address the places where RFC7752 is unclear.
RFC7752 and segment routing (SR) are in use with 
centralized controllers.  This specification addresses a known 
need in deployed SR.    Therefore it is unwise to hold this 
specification back or hurry RFC7752bis. 

There may not be substantial discussion on this point
because the people developing BGP and the people operating 
BGP realize we have a balancing act as we deploy segment routing features. 
We must balance sending forward features that aid deployments 
and clarify the RFC752bis specification so that new implementations 
may be interoperable with existing implementations. 

(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.

Jeff Tantsura (Apstra, Inc.)

 Uma Chunduri (Futurewei)

 Ketan Talaulikar (Cisco Systems)

Greg  Mirsky 

 N  Triantafillis

Contributor: Siva Sivabalan

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

WG Call for the WG approval of IPR on drafts:

Please note that the IPR on this feature  may preclude open source 
implementations from creating it. 

(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?   

11 people indicated a strong support.  
There are 2 Cisco interoperable implementations.

WG Approval of 2 Cisco implementations to send to IESG.

WG response is at:

(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 public appeals or discontent on mail list.  

(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

No NITS founds. 

(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.  

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

All references are normative. 

(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?

All normative references are RFCS. 

(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 normative references are downward references. 

(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

   This document requests assigning code-points from the registry "BGP-
   LS Node Descriptor, Link Descriptor, Prefix Descriptor, and Attribute
   TLVs" based on table below.  Early allocation for these code-points
   have been done by IANA.

       | Code Point |   Description        |     IS-IS TLV/Sub-TLV          |
       |    266     | Node MSD        | 242/23                                              |
       |    267     | Link MSD        | (22,23,25,141,222,223)/15            |

(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.

No XML code, BNF rules, MIB definitions. 
References to all Yang models have been checked.