Subject: [Gen-art] Gen-ART Last Call review of draft-ietf-6lo-6lobac-06

From: Orit Levin <[email-masked]>
Date: Mon, 28 Nov 2016 19:06:34 +0000

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.

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Document: draft-ietf-6lo-6lobac-06
Reviewer: Orit Levin
Review Date: 2016-11-26
IETF LC End Date: 2016-11-30
IESG Telechat date: (if known)

Summary:
This draft is basically ready for publication, but has editorial nits that should be fixed before publication.

Abstract:
1. Remove the word "extensively" from the first sentence.

Introduction:
1. Remove the word "extensively" from the first sentence. (Not a standard-appropriate language.)
2.Consider rephrasing to "... these constraints are similar to those faced in 6LoWPAN networks, which suggests that some elements of that solution might be leveraged."
3. Consider rephrasing the last sentence to "This document also specifies a mandatory header compression mechanism, based on [RFC6282], which reduces latency and makes IPv6 practical on MS/TP networks."

Section 1.3
1. This section is called "MS/TP Overview". The overview of the existing specifications is "mingled" with the new features and profiling defined in "this specification". By just reading this section, it is not always clear which statements refer to the "baseline" specifications and which to the new "features" defined in this document. Either consider introducing/improving "linking" sentences to clarify the text or reorganize/split the text into two independent summaries: of baseline functionality and of new functionality. 
2. In the second paragraph, rephrase to "These features make MS/TP a cost-effective field bus applicable to building an automation network." (Not a standard-appropriate language: "for the most numerous and least expensive devices".)
3. Add the word "only" to "A master node may initiate the transmission of a data frame only when it holds the token."
4. Consider changing "MS/TP COBS-encoded frame fields have the following descriptions:" to "MS/TP COBS-encoded frame fields are defined as follows:"
5. Remove "MUST"s from "Frame Types 32 - 127 designate COBS-encoded frames and MUST convey Encoded Data and Encoded CRC-32K fields.  All master nodes MUST understand Token, Poll For Master, and Reply to Poll For Master control frames." (See my first comment to this section above. Where is this defined? In the baseline specs or in this document?)

Section 3
1. Rephrase to "The method specified in Section 6 for creating a MAC-layer-derived Interface Identifier (IID) ensures that an IID of all zeros can never be generated."

Section 4
1. Consider rephrasing to "This specification restricts an MSDU length for at least 1280 octets and at most 1500 octets (before encoding)."

Section 5
1. Rephrase to "Because of the relatively low data rates of MS/TP, header compression is used as a means to reduce latency."
2. Add "of" after "comprises" in "The encapsulation format defined in this section ... comprises of the MSDU of an IPv6 over MS/TP frame."
3. In "The Dispatch value may be treated as an unstructured namespace", it would be simpler to say "is treated" unless there is a special significance to "may be". In later case, it needs to be explained.

Thank you,
Orit Levin.