[Idr] RtgDir review for draft-ietf-idr-bgp-prefix-sid-04

[Christian Hopps <[e-mail]>]

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
​http://trac.tools.ietf.org/area/rtg/trac/wiki/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-ietf-idr-bgp-prefix-sid-04
Reviewer: Christian Hopps
Review Date: 2017-03-04
IETF LC End Date: Unknown
Intended Status: Standards Track

Summary:
========

    [x] This document is basically ready for publication, but has nits that
    should be considered prior to publication.

Comments:
=========

Draft is quite readable.

Major Issues:
=============

No major issues found.

Minor Issues:
=============

References normative vs informative. I'm not sure why some of the informative
aren't normative. For example the S-bit indicates that the router is capable of
processing the SRH which is defined by [I-D.ietf-6man-segment-routing-header] so
shouldn't this be a Normative reference? Additionally the Originator SRGB TLV
references [I-D.ietf-ospf-segment-routing-extensions] for the meaning of
multiple ranges (represented by the presence of multiple TLVs).

Advisory only: There are many cases of reserved fields being "SHOULD be 0 on
transmit and MUST be ignored on receive." Is it better to use MUST instead of
SHOULD here as that allows for better future-proofing? With "MUST be 0" you
could then count on the values being zero for devices that do not support a
future extension where the value is not zero. Of course future extensions could
always use another method to determine if the reserved field holds newly valid
values so this isn't that big a deal.

Nits:
=====

By far there are more references to "nodes" than to "routers", but I think they
all refer to the same thing -- maybe pick one name.

Section 4 1st paragraph: remove first sentence starting "The value field..."

2nd paragraph: Add "The" to "Following TLVs are defined."

Section 4.3 2nd paragraph of description of SRGB (1st paragraph on page.8) uses
an unexpanded acronym SRTE.