Early Review of draft-ietf-ospf-mpls-elc-09
review-ietf-ospf-mpls-elc-09-rtgdir-early-dhody-2019-09-12-00

Subject: RtgDir Early review: draft-ietf-ospf-mpls-elc-09

Hello

I have been selected to do a routing directorate “early” review of this draft.
​https://datatracker.ietf.org/doc/draft-ietf-ospf-mpls-elc/

The routing directorate will, on request from the working group chair, perform
an “early” review of a draft before it is submitted for publication to the
IESG. The early review can be performed at any time during the draft’s lifetime
as a working group document. The purpose of the early review depends on the
stage that the document has reached.

As this document is in working group last call, my focus for the review was to
determine whether the document is ready to be published. Please consider my
comments along with the other working group last call comments.

For more information about the Routing Directorate, please see
​http://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir

Document: draft-ietf-ospf-mpls-elc-09
Reviewer: Dhruv Dhody
Review Date: 12-09-2019
Intended Status: Standards Track

Summary: I have some minor concerns about this document that I think should be
resolved before it is submitted to the IESG.

The draft is focused and straightforward, the reader needs to be aware of
RFC6790 and draft-ietf-mpls-spring-entropy-label beforehand. I have reviewed
this and the IS-IS I-D together and you will find similar comments for both
I-Ds.

Minor
*****

(1) Please use updated requirement language text as per RFC 8174, as you do
have a mix of upper-case and lower-case terms in your I-D.

      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
      "MAY", and "OPTIONAL" in this document are to be interpreted as
      described in BCP 14 [RFC2119] [RFC8174] when, and only when, they
      appear in all capitals, as shown here.

(2) Could you mark that the codepoints mentioned in the draft are early
allocated by IANA? This would make it clear that you are not squatting on them.
I also suggest following change in Section 7 (IANA Considerations) -

OLD:
   This document requests IANA to allocate one flag from the OSPFv2
   Extended Prefix TLV Flags registry:

      0x20 - E-Flag (ELC Flag)

   This document requests IANA to allocate one flag from the OSPFv3
   Prefix Options registry:

      0x04 - E-Flag (ELC Flag)
NEW:
   IANA is requested to confirm the early allocation of the following
   code point in the OSPFv2 Extended Prefix TLV Flags registry:

      0x20 - E-Flag (ELC Flag)

   IANA is requested to confirm the early allocation of the following
   code point in the  the OSPFv3 Prefix Options registry:

      0x04 - E-Flag (ELC Flag)
END

(3) Section 4, I think a reference to RFC 8476 is needed as well to state the
ERLD is advertised as part of Node MSD advertisement as defined in [RFC8476].
As mentioned in my review of the IS-IS I-D, what happens if one receives ERLD
in the Link MSD advertisement? As per my understanding this is not allowed,
better to add normative text for the case then.

(4) Section 8, suggest to also add one sentence for the impact of advertising
incorrect ERLD. If there isn't any, that can also be stated.

Nits
****
(1) Suggested ordering of sections - ..ELC/ERLD/BGP-LS/ACK..  [matching between
OSPF/ISIS]

(2) Section 2, add [I-D.ietf-mpls-spring-entropy-label] for terminology
reference

(3) Section 3, Add reference to draft-ietf-mpls-spring-entropy-label for the
definition and usage of ERLD

(4) Section 6,

   The ERLD MSD-type introduced for OSPF in Section 4 is advertised
   using the Node MSD TLV (TLV 266) of the BGP-LS Node NLRI Attribute as
   defined in section 3 of [I-D.ietf-idr-bgp-ls-segment-routing-ext].

I think you mean draft-ietf-idr-bgp-ls-segment-routing-msd here!

Also, maybe change the title "BGP-LS Extension" as there is no 'extension'
required, ELC/ERLD is BGP-LS would be automatically supported.

(5) Expand MSD on first use.

Thanks!
Dhruv