IETF Last Call Review of draft-ietf-v6ops-rfc6146-bis-07
review-ietf-v6ops-rfc6146-bis-07-tsvart-lc-ott-2026-06-29-00

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.

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The document describes algorithms and timers for the operation of a NAT64 for
the protocols TCP, UDP, and ICMP.

The draft is well-written and appears clear.  Minor nits below.

From a transport perspective, the single question is why the document focuses
TCP, UDP, and ICMP and does not consider DCCP and SCTP, without any reasons
given.  While it is obvious that those former three protocols dominate global
Internet traffic, one may ask if explicitly leaving out the other two IETF
standardized protocols wouldn't (further) contribute to lack of support for
them in middleboxes.

The text has motivations in different places (e.g., for TCP simultaneous open
-- please define briefly -- or RST packet processing), which is nice.  It may
be useful to have some convention how to indicate such motivational text (in
brackets or so).  Moreover, it may be useful to have the text then appear as a
separate paragraph rather than inline.

Sect 3.5.1 (p.22 of the PDF, 3rd para): Referring to RTP/RTCP for port parity
preservation may be outdated by now.  Still needed?

Nits: advices -> advice
Sect. 8.2 "Without filtering" -- is the "However" at the end of the paragraph
intentional to lead over to the next bullet?

Best,
Jörg