Last Call Review of draft-ietf-6man-grand-04
review-ietf-6man-grand-04-tsvart-lc-scharf-2021-06-08-00

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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This update to the IPv6 Neighbor Discovery does not directly affect Internet
transport protocols. There are no apparent TSV issues that would prevent
progressing the document.

Nonetheless, I found some small nits:

* Section 1: The last sentence "It can cause user-visible packet loss and
performance degradation." may be a bit misleading. If a reliable transport
protocol is used, packet loss is typically _not_ directly visible to the user.
In many cases it may just result in user-visible performance degradation such
as delays (e.g., delays of the TCP connection setup). A better wording would be:

  "It can cause packet loss and performance degradation that can be
  user-visible."

* Section 3: I am not sure if BCP 14 capital latter language is needed in
Section 3. At least, use of BCP 14 terms should be consistent inside Section 3.
I find it confusing that capital letters are used in some requrirements but not
in all. An easy fix would be not to use BCP 14 language in this section.

* Section 8.7: The list of drawbacks may not be comprehensive. For instance, I
suspect that reducing the probe retransmit interval could increase the risk of
congesting a link that is already under load. If so, this would be another
reason not to use the mechism discussed in Section 8.7.