[tcpm] AD Review of draft-ietf-tcpm-hystartplusplus-09

[Martin Duke <[e-mail]>]

Thank you for this concise and very readable document.

My only major concern is the old subject of RFC3465 (ABC) being
Informative, but a downref if we make it Normative. In my opinion, the
document as written is not implementable without 3465 and it should be a
normative reference.

If I am correct about the status quo, the only part of 3465 that is not in
5681 (and therefore still Experimental) is the use of L > 1 in slow start.

There are three approaches to handling this problem.

1. Eliminate L from the spec, and use the RFC5681 slow start formula.
What's bad about this is that IIUC we have no data with L=1. But we could
say in Section 5 that the tests also used RFC 3465 with L=8 and the market
decide what to do with that.

2. Send to the RFC Editor with a normative reference; the doc will be
"done", but will not publish until ABC goes to PS (which is not imminent,
to say the least).

3. What I think you've actually done here is standardized RFC3465 behavior
only when combined with CSS (i.e. a partial promotion of ABC). I think this
is the best course of action, but if we're going to do that, we should go
all the way:

(a) Add a definition of L and a discussion of how to set it -- basically
Sec 2.3 of RFC3465 but presumably with no L=2 limit. If we're going to
publish a standard with a higher cap on L we really ought to have that
discussion.

(b) It can "update" or "obsolete" 3465 depending on whether or not the WG
cares to keep the experimental status of ABC-without-CSS.

The community apparently has consensus that L > 1, even L >  2, *in this
context* is safe, so I don't see it as reckless to make this change.

I'm happy to have a dialogue about this.

NITS:
(3) s/definition/definitions

(4.1) "The Inter Packet Arrival algorithm does not perform well." If
there's a useful citation here (or for the results discussed in Section 5)
that would be nice to include.

(4.1) s/it's concluded that/the algorithm concludes

Thanks again!
Martin