Last Call Review of draft-ietf-ntp-chronos-16
review-ietf-ntp-chronos-16-tsvart-lc-pauly-2023-06-19-00

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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review as part of the last-call comments they receive. Please always CC
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I have no concerns about this document from the transport perspective. Its use
of DNS queries and NTP transactions has a very low rate (intended to not
overwhelm servers), and doesn't raise any new concerns. This document also
doesn't add any new mechanisms that would affect usage of transport mechanisms,
ports, etc.

The document is clear and concise, although I have two nits for clarity:

- In Section 1, the term "Byzantine attackers" is used without reference or
explanation. Later, it does have a forward reference to the security section. I
suggest adding a forward reference or an external reference to explain the
attack, and potentially add a bit more context within the text to help readers
who are not familiar with that kind of attack. - A block diagram or other
illustration would be much appreciated in section 3 to help explain how the
Khronos function exists alongside current client software, and what servers it
is interacting with. I'm not sure how feasible such an image would be, but I
think it would make the document more easily understood.