Subject: Genart last call review of draft-ietf-mpls-rfc8287-len-clarification-02

From: Ines Robles via Datatracker <[email-masked]>
Date: Tue, 30 Jul 2019 05:11:31 -0700

Reviewer: Ines Robles
Review result: Ready with Issues

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.

Document: draft-ietf-mpls-rfc8287-len-clarification-02
Reviewer: Ines Robles
Review Date: 2019-07-30
IETF LC End Date: 2019-07-31
IESG Telechat date: Not scheduled for a telechat

Summary:

I believe the draft is technically good. This document is well written.

The document updates RFC8287 by clarifying the length for the following Segment
ID Sub-TLVs: IPv4 IGP-Prefix Segment ID Sub-TLV, IPv6 IGP-Prefix Segment ID
Sub-TLV and IGP-Adjacency Segment ID Sub-TLV.

There are some minor issues detailed below that should be addressed.

Major issues: Not found

Minor issues:

1- Section 3 - Requirements notation is not complete, it should be added:  "NOT
RECOMMENDED" and "...are to be interpreted as described in BCP 14 [RFC2119]
[RFC8174] when, and only when, they appear in all capitals, as shown here."

2- Figure of Section 4.2: Type = 35 (IPv4 IGP-Prefix SID) ---> Type = 35 (IPv6
IGP-Prefix SID)

2.1- It would be nice if the figures have a caption where we can point to the
figure number, and the figure number is referenced in the text. The same for
the table of Section 4.3.

3- Question: What do you think?

I think it would be nice to explain a bit more the length for the different
combinations of the table of Section 4.3, e.g. with tables as detailed below:

+-----------------------------+-------------------+
|            Field                               | Parallel (octets) |
|     rfc8287#section-5.3            +-----+------+------+
|                                                       | Any | OSPF | ISIS |
+-----------------------------+-----+------+------+
|      Local Interface ID                    |  4  |   4  |   4  |
+-----------------------------+-----+------+------+
|     Remote Interface ID                 |  4  |   4  |   4  |
+-----------------------------+-----+------+------+
| Advertising Node Identifier          |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|  Receiving Node Identifier             |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|           Reserved                                 |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|     Adj. Type + Protocol                     |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|       Sum Total octets =                      |  20 |  20  |  24  |
+-----------------------------+-----+------+------+

+-----------------------------+-------------------+
|            Field                                |   IPv4 (octets)   |
|     rfc8287#section-5.3             +-----+------+------+
|                                                        | Any | OSPF | ISIS |
+-----------------------------+-----+------+------+
|      Local Interface ID                     |  4  |   4  |   4  |
+-----------------------------+-----+------+------+
|     Remote Interface ID                 |  4  |   4  |   4  |
+-----------------------------+-----+------+------+
| Advertising Node Identifier           |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|  Receiving Node Identifier             |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|           Reserved                                  |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|     Adj. Type + Protocol                     |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|       Sum Total octets =                     |  20 |  20  |  24  |
+-----------------------------+-----+------+------+

+-----------------------------+-------------------+
|            Field                                |   IPv6 (octets)          |
|     rfc8287#section-5.3           +-----+------+------+
|                                                       | Any | OSPF | ISIS |
+-----------------------------+-----+------+------+
|      Local Interface ID                    |  16 |  16  |  16  |
+-----------------------------+-----+------+------+
|     Remote Interface ID                  |  16 |  16  |  16  |
+-----------------------------+-----+------+------+
| Advertising Node IdentifieR           |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|  Receiving Node Identifier              |  4  |   4  |   6  |
+-----------------------------+-----+------+------+
|           Reserved                                  |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|     Adj. Type + Protocol                     |  2  |   2  |   2  |
+-----------------------------+-----+------+------+
|     sum  Total octets =                       |  44 |  44  |  48  |
+-----------------------------+-----+------+------+

Nits/editorial comments: Issue tool: Summary: 0 errors (**), 0 flaws (~~), 0
warnings (==), 1 comment (--).

Thanks for this document,

Ines