Hello,

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 https://wiki.ietf.org/en/group/rtg/RtgDir

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-name-version
Reviewer: your-name
Review Date: date
IETF LC End Date: date-if-known
Intended Status: copy-from-I-D

Summary:
I have significant concerns about this document and recommend that the Routing ADs discuss these issues further with the authors.

Comments:

I was very pleased with the clarity and readability of the document.  It lays out the space it is working in, and explains what it does and how very well.

Major Issues:
    I have significant concern with the structure of the TLVs in two regards.
    First, the PeerAdj SID Sub-TLV (assigned tbd1 in section 4, defined in section 4.1) uses a single code point for IPv4 and IPv6 and differentiates by length.  Other sub-TLVs for MPLS ping and traceroute use different code points for IPv4 and IPv6.
    Second, all of the sub-TLVs defined in section 4 have length codes.  Looking at RFC 8029, sub-TLVs are defined with fixed lengths and do not have length codes embedded in them.  While one can argue that this is a bad practice, it is the practice, and RFC 8287 follows that practice.  It would seem this document should do so as well.

Minor Issues:
    It would be helpful if the document directly referenced RFC 8029 and said that 8029 is where the TLVs that can carry these sub-TLVs is defined.  That should be a normative reference.