[tsvwg] John Scudder's No Objection on draft-ietf-tsvwg-dscp-considerations-12: (with COMMENT)

[John Scudder via Datatracker <[e-mail]>]

John Scudder has entered the following ballot position for
draft-ietf-tsvwg-dscp-considerations-12: No Objection

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)


Please refer to https://www.ietf.org/about/groups/iesg/statements/handling-ballot-positions/ 
for more information about how to handle DISCUSS and COMMENT positions.


The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-tsvwg-dscp-considerations/



----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

# John Scudder, RTG AD, comments for draft-ietf-tsvwg-dscp-considerations-12
CC @jgscudder

## COMMENTS

Thanks for this interesting document, I enjoyed reading it. I have a number of
comments that I hope will be helpful; I'm somewhat concerned they may come off
as nitpicking but in some of the cases I really did find that (for example)
lack of a comma seriously impeded my ability to understand the material.

### Section 1, Expand "BA"

Please expand "BA" on first use, presumably you'd do this by putting "(BA)"
next to your first and only use of "Behavior Aggregates".

### Section 2, The term 'remarking'

You might mention in your Terminology section that you use the term "remarking"
in a nonstandard (with respect to the normal rules of English orthography) way,
pronounced and construed as "re-marking". Then again, maybe the entire document
set around DSCP already has this quirk so the ship has sailed? Your call, but
you do say in Section 6 that your intended audience is the entire IETF and
IESG, so it might be worth erring on the side of generosity here.

### Section 3.1, Unclear clause

The parenthetical

        where 'x' refers to either a bit position with value '0' or '1'

Is unclear, probably what you mean is

        where 'x' refers to a bit position with value either '0' or '1'

### Section 3.1, Pool 3

I found the discussion of 0x01, 0x03, 0x05, 0x07 under the heading of Pool 3 to
be confusing, considering that we are told Pool 3 has format 0bxxx01, and so
0x03 and 0x07 are by definition not part of it. Would it make sense to end the
description of Pool 3 right after "... if Pool 1 is ever exhausted" and make
the remaining text a standalone paragraph and not part of the Pool 1/2/3
hanging list?

### Section 3.2, For want of a comma, the point was lost

I wasn't able to unambiguously construe

```
Similarly, another study found many routers remark all traffic except those
packets with a DSCP that sets the higher order bits to 0b11 (see Section 4 of
this document). ```

until I finally found the answer in the final paragraph of Section 4.2.1. So,
at the very least you might update your reference to point the bamboozled
reader specifically to that paragraph or at least subsection. I would also
suggest at minimum adding a comma between "traffic" and "except", but really
why not just rewrite it in a way that's a bit more direct?

### Section 4.2.1, Gnomic entries in Table showing 0b000xxx DSCPs

I was expecting that some later text would help me understand what "ToS Prec
B1. of AF11..41", "EXP/LU", "ToS Prec B1 of AF13..EF" and "Exp/LU" mean, but
none ever came. I surmise that the "ToS Prec" business means "these are
assigned things that ToS-bleach down to the same thing", but really the work to
figure that out was greater than the work to just read the preceding "Table of
DSCP values" and come to the conclusion myself. And neither "EXP/LU" nor
"Exp/LU" (why the different capitalizations?) are ever explained.

It seems to me that this table is too pithy to be of use to the casual reader
such as myself, and likely too obvious to be of use to the expert reader.

### Section 4.2.1, Is LE 1, or 4?

You write "The Lower-Effort Per-Hop Behavior PHB (LE) uses a DSCP of 4". But
elsewhere (the "Table of DSCP values", other tables, Section 6.2.1) you tell me
LE is DSCP 1.

### Section 5.1.1 Including? Included?

"IEEE 802.1Q specified a 3-bit Priority Code Point (PCP) field including in a
tag that allows Ethernet frames to be marked as one of eight priority values
[IEEE-802-1Q]."

I don't know from 802.1Q, so I can't work out if there's a comma missing before
"including", or if "including" should be "included". (Or something else I
haven't contemplated.)

## NITS

"as well unassigned DSCPs" -> "as well as unassigned DSCPs" (insert 'as')

## Notes

This review is in the ["IETF Comments" Markdown format][ICMF], You can use the
[`ietf-comments` tool][ICT] to automatically convert this review into
individual GitHub issues.

[ICMF]: https://github.com/mnot/ietf-comments/blob/main/format.md
[ICT]: https://github.com/mnot/ietf-comments