Erik: correct or remove erroneous note in Step 3 of the fragmentation procedure (Section 11.4)

[Mike-Heard]

In https://mailarchive.ietf.org/arch/msg/tsvwg/SjPKGD-yxp2-Cf7TFGyKCCA7e8I/, Erik Auerswald wrote:

I do not understand the "Note" in enumeration item 3 of the fragmentation procedure in section 11.4, "Fragmentation (FRAG)" on page 25:

 "Note: per packet options can occur either at the end of the
  original user data or be placed after the FRAG option of the
  first fragment, with the Reassembled Datagram Option Start (RDOS)
  in the terminal FRAG option set accordingly. This includes its
  use in atomic fragments, where the terminal option is the initial
  and only fragment."

How exactly would RDOS be set to indicate that the per-packet (a.k.a per-datagram) options are located outside the reassembled datagram after the FRAG option of the first fragment[, but before the fragment data], in the case non-atomic fragments? RDOS is a positive offset from the start of the reassembled datagram (a.k.a. packet).

It seems to me as if this note should be deleted. Alternatively, it could be simplified to pertain only to atomic fragments, e.g.:

  In atomic fragments, where the the terminal option is the initial
  and only fragment, both per-fragment and per-datagram options
  affect the same UDP payload.

[Mike-Heard]

The correct solution is to delete the whole paragraph, since there are now explicit instructions in the definition of each option on how to collect per-fragment options and pass them to the user/application. Note that the definition of APC is such that it is not useful as a per-fragment option, even in an atomic fragment; it must be sent as a per-datagram option in order to be useful.

Note that the updated text submitted to close Issue #2 had this paragraph deleted; that change did not make it into the -23 draft. My apologies for having missed that.

[Mike-Heard]

In https://mailarchive.ietf.org/arch/msg/tsvwg/DtWdOh9sGcoPMJAC8Mb-Pp_q9iM/, Erik Auerswald wrote:

You are right, my suggested replacement is wrong. I concur that the paragraph should be deleted.

Best regards, Erik