Last Call Review of draft-ietf-detnet-mpls-04
review-ietf-detnet-mpls-04-rtgdir-lc-pignataro-2019-12-23-00

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
​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-detnet-mpls-04
Reviewer: Carlos Pignataro
Review Date: December 2019
Intended Status: Proposed Standard

Summary:

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

[Resolving, in this context, means discussing and responding to, some of these
would and others would not imply changes]

This document specifies the Deterministic Networking data plane when operating
over an MPLS Packet Switched Networks.

Major Issues:

Minor Issues:

The document lists 7 (i.e, more than 5) authors.

A am somewhat confused regarding how some of these DETNET dataplane documents
interact, interface, and intersect with each other. Where are requirements
ultimately coming from for any variety of dataplanes? Specifically: *
draft-ietf-detnet-data-plane-framework-03 targets Informational (should be
STD?) but seems to include foundational Reqs. * draft-ietf-detnet-ip for IP *
draft-ietf-detnet-ip-over-mpls for IP over MPLS * draft-ietf-detnet-ip-over-tsn
and draft-ietf-detnet-mpls-over-tsn for X over TSN *
draft-ietf-detnet-mpls-over-udp-ip and draft-ietf-detnet-mpls for MPLS Among
all of these, where are really the requirements for MPLS? and for IP? Is there
a "Roadmap" or Rosetta Stone to understand these? There are many permutations
of X-over-Y. I appreciate that, not having followed DETNET discussions, I am
likely missing something.

3.1.  Layers of DetNet Data Plane

   The DetNet control word (d-CW)
   conforms to the Generic PW MPLS Control Word (PWMCW) defined in
   [RFC4385].

Yes, but why not the Preferred CW?

4.1.  DetNet Over MPLS Encapsulation Components

   The LSP used to forward the DetNet packet may be of any type (MPLS-
   LDP, MPLS-TE, MPLS-TP [RFC5921], or MPLS-SR
   [I-D.ietf-spring-segment-routing-mpls]).

I am not sure of the value of this statement for an "MPLS Dataplane" document.
Further, are these "LSP Types" and if so where are the different types
ennumerated? Does this mean that static binding LSPs and BGP signaled cannto be
used? T-LDP does not work? "SDN Assigned"? I recommend removing this, since it
can confuse and does not add much.

4.3.  OAM Indication

It is important to have the OAM Indication, but what type of OAM packets can
run on top of this AcH? I found it interesting that for example there is not
reference or citation to RFC 8029.

Nits:

2.2.  Abbreviations

   The following abbreviations are used in this document:

Many of these abbreviations are well-known, many others have authoritative
definitions and expansions. I believe this section should point to the
appropriate RFCs for LSR, CW, PE, OAM, etc...

Also, interesting, this section does not expand LSE, and I think it should use
it.

4.6.1.  Class of Service

Should this include "and TTL" in the title? I was looking for TTL specs in the
Table of Contents but could not find it.

9.2.  Informative References

Are all the "draft-ietf-detnet-*" really Informative?

Also, outdated reference: draft-ietf-spring-segment-routing-mpls has been
published as RFC 8660

   [RFC8655]  Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,
              <https://www.rfc-editor.org/info/rfc8655>.

And is this also Informational?

Thank you!

Carlos Pignataro.