Last Call Review of draft-ietf-6lo-plc-05
review-ietf-6lo-plc-05-tsvart-lc-touch-2021-02-19-00

Request Review of draft-ietf-6lo-plc
Requested rev. no specific revision (document currently at 06)
Type Last Call Review
Team Transport Area Review Team (tsvart)
Deadline 2021-02-19
Requested 2021-02-01
Authors Jianqiang Hou, Bing Liu, Yong-Geun Hong, Xiaojun Tang, Charles Perkins
Draft last updated 2021-02-19
Completed reviews Tsvart Last Call review of -05 by Joseph Touch (diff)
Opsdir Last Call review of -05 by Dan Romascanu (diff)
Secdir Last Call review of -05 by Robert Sparks (diff)
Genart Last Call review of -05 by Meral Shirazipour (diff)
Assignment Reviewer Joseph Touch 
State Completed
Review review-ietf-6lo-plc-05-tsvart-lc-touch-2021-02-19
Posted at https://mailarchive.ietf.org/arch/msg/tsv-art/EvaglYYQvdUiislXJKUxv_3nWDU
Reviewed rev. 05 (document currently at 06)
Review result Ready with Issues
Review completed: 2021-02-19

Review
review-ietf-6lo-plc-05-tsvart-lc-touch-2021-02-19

This document has been reviewed as part of the transport area review team's
ongoing effort to review key IETF documents. These comments were written
primarily for the transport area directors, but are copied to the document's
authors and WG to allow them to address any issues raised and also to the IETF
discussion list for information.

When done at the time of IETF Last Call, the authors should consider this
review as part of the last-call comments they receive. Please always CC
tsv-art@ietf.org if you reply to or forward this review.

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The only significant transport issue in this doc is the issue of MTU support. Secs 3.3 and 4.6 refers to underlying frag/reassembly per RFC4944. First, these sections seem redundant; normative requirements should appear in only one section if both are retained. 

More notably, the use of a 16-bit tag in that spec is already known to be problematic for IPv4 fragmentation and could cause problems here as well, e.g., per RFC4963. This issue should be addressed, notably if there is a reason why a 16-bit tag is considered sufficient for this use it should be stated or some other shim layer should be proposed with a more robust tag (e.g., 32 bits).

Some minor additional suggestions follow:

The intro refers to “6lo”; this term should be defined before being used. The scenarios should include a citation if available. Similarly, LLN should be defined. Work that did not receive consensus might be mentioned elsewhere or even omitted completely, but seems premature in the intro. Also, “the previous work” in the last sentence is ambiguous; it would be useful to refer to the RFCs, the draft, or whatever else to which it refers.

Sec 3 includes “Moreover, recently a new …”, which seems redundant; it might be just “A new…”. Again, this section (and later ones too) refers to “6lo” as a category of sorts, which needs to be defined (and included in the acronym/terminology list).