[tcpm] Secdir early review of draft-ietf-tcpm-accurate-ecn-30

[Scott Kelly via Datatracker <[e-mail]>]

Reviewer: Scott Kelly
Review result: Ready

I have reviewed this document as part of the security directorate's ongoing
effort to review all IETF documents being processed by the IESG. These comments
were written primarily for the benefit of the security area directors. Document
editors and WG chairs should treat these comments just like any other last call
comments.

The summary of the review is Ready.

I did an early review of this document in April of 2021. At that time, I said
I'm not a TCP or ECN expert, so please take my comments with a proverbial grain
of salt. Nothing has changed, I am still not a TCP or ECN expert.

The security considerations in the original draft contained a TODO about a
potential covert channel; this document still contains the TODO. I think this
should be resolved before publication, but I leave this to the AD. I have
nothing new to add.