[tsvwg] Alissa Cooper's Discuss on draft-ietf-tsvwg-rfc5405bis-18: (with DISCUSS)

["Alissa Cooper" <[e-mail]>]

Alissa Cooper has entered the following ballot position for
draft-ietf-tsvwg-rfc5405bis-18: Discuss

When responding, please keep the subject line intact and reply to all
email addresses included in the To and CC lines. (Feel free to cut this
introductory paragraph, however.)


Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.


The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-tsvwg-rfc5405bis/



----------------------------------------------------------------------
DISCUSS:
----------------------------------------------------------------------

= Section 3.17 =

"An application sending ECN-capable datagrams MUST provide an
      appropriate congestion reaction when it receives feedback
      indicating that congestion has been experienced.  This must result
      in reduction of the sending rate by the UDP congestion control
      method (see Section 3.1) that is not less than the reaction of TCP
      under equivalent conditions."
    
Is the second "must" meant to be normative? If so, this worries me a bit.
RFC 6679 I believe retains flexibility for endpoints to react to
congestion in ways that are different from TCP and dependent on specific
codecs, topologies, and other factors. RFC 3551 provides a lot of
qualification in the requirements it places around equivalence to TCP's
behavior. So I would be concerned about how this requirement, if
normative, would affect RTP and other protocols.

If it's not meant to be normative, I would suggest using "ought to" or
some other word.