Skip to main content

Shepherd writeup

Version 11/1/2019: As required by RFC 4858, this is the current template for
the Document Shepherd Write-Up.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet
Standard, Informational, Experimental, or Historic)? Proposed Standard

Why is this the proper type of RFC?  This document defines a new BGP SAFI with
a new NLRI to advertise a candidate path of a segment routing (SR) Policy.

Is this type of RFC indicated in the title page header?  Yes

(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 new BGP SAFI with a new NLRI to advertise
a candidate path of a segment routing (SR) Policy.   An SR Policy is
a set of candidate paths, each consisting of one or more segment lists.
The headend of an SR Policy may learn multiple candidate paths for
an SR Policy.  Candidate paths may be learned via several different mechanisms
(e.g. CLI, NETCONF, PCEP, or BGP).  This document specifies how BGP
may be used to distribute SR Policy candidate paths.  New Sub-TLVs for the
BGP tunnel Encapsulation Attribute are defined for signaling
information about these candidate paths.

Working Group Summary:
[WG LC: 6/29/2021 to 7/13/2021]

John's Scudder's update:

RTG-DIR (early review):

Document Quality:

Are there existing implementations of the protocol?
5 implementations:  Cisco-IOS-XR, Arista EOS, Juniper, Nokia, Huawei

Have a significant number of vendors indicated their plan to implement the
specification? Yes.

Document Shepherd: Susan Hares
AD: Alvaro Retana
Early reviews:
a) secdir-review: status: ready, Reviewer: Vincent Roca
b) opsdir-review: status: not filled out
c) intdir-review: status: ready with issues reviewer: Brian Haberman
d) rtgdir-review: status: has issues:  Reviewer: Mohamed Boucadair

mail thread indicates editor has resolved issues with Mohamed.

(3) Briefly describe the review of this document that was performed by the
Document Shepherd. This document has been reviewed by the Document shepherd (3
times). The shepherd also asked for targeted reviews. The implementation report
was repeatedly reviewed.

7+ implementation exist (including 1 open-source implementation).

The WG approved sending the document even though some portion of the document do
not have 2 implementations.

The email sequence regarding the last shepherd report (-17 to -18)  is given

The IDR Mail list discussion on approving without all features being
implemented is here:

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

(4) Does the document Shepherd have any concerns about the depth or breadth of
the reviews that have been performed? No

(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. Directorates
from Security, INT, RTG and OPS Area were asked for early review.

(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 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? IPR disclosures: Stefano Previdi

Clarence Filsfils

Ketan Talulikar

Paul Mattes

Eric Rosen:

Dhanendra Jain:

Stephen Lin

Arjun Sreekantiah

Acee Lindem

Siva Sivabalan

Imtiyaz Mohammad

Gurav Dawra

Peng Shaofu

(8) Has an IPR disclosure been filed that references this document?
Yes - See 2984 via datatracker link.
If so, summarize any WG discussion and conclusion regarding the IPR disclosures.
This IPR was filed before IDR WG adopted draft.

(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? WG consensus is good to strong.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent?
If so, please summarize 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 appeals or extreme discomfort

(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. ID Nits
run. No errors.

(12) Describe how the document meets any required formal review criteria, such
as the MIB Doctor, YANG Doctor, media type, and URI type reviews. No formal
review required. Packets only.

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

(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 documents are
RFCs or at RFC Editor.

(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.

(16) Will publication of this document change the status of any existing RFCs?
RFC9012. Listed on title page, included in abstract, and discussed in

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the

IANA has reviewed the permanent allocations for this draft, and allocations.

(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. Section 6.5   New
Registry: SR Policy Segment List Sub-TLVs Section 6.6.  New Registry: SR Policy
Binding SID Flags Section 6.7.  New Registry: SR Policy SRv6 Binding SID Flags
Section 6.8   New Registry: SR Policy Segment Flags Section 6.9.  New Registry:
Color Extended Community Color-Only Types

(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, YANG modules, etc.

(20) If the document contains a YANG module, has the module been checked with
any of the recommended validation tools
( for syntax and
formatting validation? No yang module for this document. The IDR Chairs will
add this to the list of BGP-LS modules that need to be created after BGP main
module is finished.