Re: [tsvwg] I-D Action: draft-ietf-tsvwg-udp-options-13.txt

[Joseph Touch <[e-mail]>]

Here’s a summary - I tried to catch both everything Mike provided feedback on as well as what I have proposed as a way forward.

AFAICT, there are also two things not yet addressed, in addition to ongoing debate on the changes below:
How many frags MUST be supported 2? 4?
Should we change UNSAFE from a single code point to a range (but not a flag), and if so, what range of codepoints is sufficient (32? 16?)

Joe

Frag 
Drops integrated checksum
Includes a start pointer so all per-frag options can come before the frag data
Terminal includes an endpointer so options can come after
This new format means that per-frag options always come before all FRAG data, which enables zero-copy
OCS
Uses the standard 2-byte prefix (all but NOP and EOL do)
Added discussion of RFC 6935 regarding exception to requiring the UDP checksum and thus OCS
Allow OCS’s checksum to be precomputed, but still check in the order options occur
Occurs over the entire surplus area (doesn’t stop at EOL)
NOP
Increased max in a row from three to  seven
AE
Split into AUTH (safe) and ENCR (UNSAFE)
AUTH can depend on option data
ENCR can depend on but not modify option data
Only one is ever used at a time, though (that’s one reason it was presented as AE before)
EOL
MUST set as zero on transmit, MAY check on receipt, but MUST ignore otherwise.
post-EOL always were covered by OCS and still are
UDP Length vs extended length
Always use the smallest format, as Mike suggested
Option length errors
Corrected to fail only on nonsensical values, otherwise skip as unknown
ACS
Silently ignored if failed except if configured otherwise
Unknown lengths treated same as bad checksum
EXP
Showed extended length format
UNSAFE
Noted extended length format also applies
Cannot modify option data
UDP-lite
Removed implied equivalence to FRAG, but retained remainder  as useful context

> On Jun 19, 2021, at 12:32 AM, [e-mail] wrote:
> 
> 
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the Transport Area Working Group WG of the IETF.
> 
>        Title           : Transport Options for UDP
>        Author          : Joe Touch
> 	Filename        : draft-ietf-tsvwg-udp-options-13.txt
> 	Pages           : 37
> 	Date            : 2021-06-19
> 
> Abstract:
>   Transport protocols are extended through the use of transport header
>   options. This document extends UDP by indicating the location,
>   syntax, and semantics for UDP transport layer options.
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-tsvwg-udp-options/
> 
> There is also an htmlized version available at:
> https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-udp-options-13
> 
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-tsvwg-udp-options-13
> 
> 
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
> 
>