Last Call Review of draft-ietf-lpwan-coap-static-context-hc-12
review-ietf-lpwan-coap-static-context-hc-12-tsvart-lc-touch-2020-02-12-00

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.

When done at the time of IETF Last Call, the authors should consider this
review as part of the last-call comments they receive. Please always CC
tsv-art@ietf.org if you reply to or forward this review.

I found no transport issues with this document.

However, this document normatively cites ietf-lpwan-ipv6-static-context-hc,
which does have some transport issues of concern. I am listing them here
because of the dependency between the two documents.

In particular, ietf-lpwan-ipv6-static-context-hc overlooks the case where the
IP header indicates a packet longer than the UDP header, a case that is
currently being developed for UDP header options in TSVWG. This other document
claims that both UDP and IPv6 length fields can be computed from the received
data, but this is not the case when the IP header indicates a packet end after
that of the UDP header. See draft-tsvwg-udp-options for more information.

There are no changes needed to this document to address this length issue, but
the normative dependency in this doc is the reason for indicatin this document
as "Almost Ready".