[MMUSIC] Changes for draft-ietf-mmusic-trickle-ice-sip-14 - ABNF

[Thomas Stach <[e-mail]>]

All,

during IESG review we got the below proposal by Adam for changing the 
ABNF to allow for more encoding flexibility.

Unless somebody objects, I'd provide the proposed change by end of the week.

It would affect the "session-level-fields" as proposed below and in a 
similar way the  "pseudo-media-descriptions" and
"trickle-ice-attribute-fields"

Excerpt from Adam'S IESG review:

§9.2:

The syntax for "session-level-fields", "pseudo-media-descriptions", and
"trickle-ice-attribute-fields" include extremely strict rules around 
ordering of
fields (e.g., including ice-ufrag before ice-pwd would be syntactically
invalid). That level of strictness seems unlikely to lead to interoperable
implementations.

If the intention is to be rigid in this fashion, please add prominent prose
that warns implementors that fields MUST appear in the order specified, and
that all other orders are invalid and MUST be rejected.

If that's *not* your intention (and I suspect it isn't), then please fix 
the
syntax definition to allow for arbitrary ordering of attributes in the 
same way
as SDP does. For example:

      session-level-fields = *(session-level-field CRLF)

      session-level-field = bundle-group-attribute /
                            ice-lite-attribute /
                            ice-pwd-attribute /
                            ice-ufrag-attribute /
                            ice-options-attribute /
                            ice-pacing-attribute /
                            end-of-candidates-attribute /
                            extension-attribute-fields
                                   ; for future extensions


Regards

Thomas