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Early Review of draft-ietf-spring-sr-yang-28

Request Review of draft-ietf-spring-sr-yang
Requested revision No specific revision (document currently at 30)
Type Early Review
Team Routing Area Directorate (rtgdir)
Deadline 2020-12-07
Requested 2020-11-16
Requested by Martin Vigoureux
Authors Stephane Litkowski , Yingzhen Qu , Acee Lindem , Pushpasis Sarkar , Jeff Tantsura
I-D last updated 2020-12-08
Completed reviews Yangdoctors Early review of -09 by Ladislav Lhotka (diff)
Yangdoctors Last Call review of -20 by Ladislav Lhotka (diff)
Rtgdir Early review of -28 by Tal Mizrahi (diff)
Assignment Reviewer Tal Mizrahi
State Completed
Request Early review on draft-ietf-spring-sr-yang by Routing Area Directorate Assigned
Posted at
Reviewed revision 28 (document currently at 30)
Result Has issues
Completed 2020-12-08

I have been selected as the Routing Directorate reviewer for this
draft. The Routing Directorate seeks to review all routing or
routing-related drafts as they pass through IETF last call and IESG
review, and sometimes on special request. The purpose of the review is
to provide assistance to the Routing ADs. For more information about
the Routing Directorate, please see

Although these comments are primarily for the use of the Routing ADs,
it would be helpful if you could consider them along with any other
IETF Last Call comments that you receive, and strive to resolve them
through discussion or by updating the draft.

Document: draft-ietf-spring-sr-yang-28
Reviewer: Tal Mizrahi
Review Date: 08-Dec-2020
Intended Status: Standards Track

I have some minor concerns about this document that I think should be
resolved before publication.

The document defines a YANG data model for MPLS segment routing. The
document is in good shape, and I believe it is almost ready for

My comments are mainly about the need for a clear definition of the
scope of the document. While these comments do not require major
changes in the document, a bit of rephrasing and clarifying text will
go a long way here.

- The document is focused on SR-MPLS, while RFC8402 discusses both
SR-MPLS and SRv6. I am sure there is a good reason for this, but it is
important to point out at the very beginning of the document that it
does not cover SRv6 and preferably also the reason for this.
- It is important to clarify the scope of the YANG models in the
introduction: do they refer only to SR routers, or also to SR
ingress/egress nodes?
- The Common Types module is mentioned for the first time in Section
8. It would be appropriate to mention it and describe its purpose in
Section 3.
- In the following text it would be more accurate to replace: "with
Segment Routing (SR)." ==> "with MPLS Segment Routing (SR)."

         "This augments routing data model (RFC 8349)
          with Segment Routing (SR).";