Re: [MMUSIC] "New" style for defining SDP attributes

Hi,

>I couldn't find ABNF for ice-lite-attribute, pwd-attribute, ice-ufrag-attribute, ...
>Once it's there I'll take it.

Section 4.

You don’t need the “a=” part, because that is implicit for attributes.

Regards,

Christer

On 2018-05-14 20:02, Christer Holmberg wrote:

Hi,

Note that I changed the subject line here. My intent was to start a different discussion that >isn't specifically related to trickle-ice-sip.

The intent instead is to discuss if we should change 4566bis to be more explicit about how >to define attributes.

Sure.

But, at the same time we'd like to move trickle-ice-sip forward, and I think my suggestion below allows us to do that while any possible change to 4566bis is discussed.

Regards,

Christer

On 5/13/18 4:47 AM, Christer Holmberg wrote:

Hi,

My suggestion would be to simply reference the syntax. Something like:

trickle-ice-sdpfrag =   session-level-fields

                                        pseudo-media-descriptions

session-level-fields = bundle-group-attribute CRLF          \

                                        ice-lite-attribute CRLF                      \

                                        ice-pwd-attribute CRLF                     \

                                        ice-ufrag-attribute CRLF                    \

                                        ice-options-attribute CRLF                \

                                        ice-pacing-attribute CRLF                  \

                                        end-of-candidates-attribute CRLF   \

                                        extension-attribute-fields

The attribute fields follow the generic syntax for SDP attributes [RFCXXXX]. The list below reference the specific syntax for each attribute field.

ice-lite-attribute              ; as ice-lite defined in [RFCXXXX]

ice-pwd-attribute            ...

ice-ufrag-attribute           ...

ice-pacing-attribute         ...

ice-options-attribute       ....

Then we don't need to worry about "new" and "old" in this draft. We simply define the high-level syntax for the sdpfrag message body, and reference the appropriate specifications for the attributes etc.

In addition, I think it would be useful to say that in order to use an extension attribute, there needs to be a specification for how that attribute is used within a sdpfrag message body. Otherwise someone could include any SDP attribute just like that.

Regards,

Christer

-----Original Message-----

From: mmusic [mailto:mmusic-bounces@ietf.org] On Behalf Of Paul

Kyzivat

Sent: 12 May 2018 19:41

To: mmusic@ietf.org<mailto:mmusic@ietf.org>

Subject: [MMUSIC] "New" style for defining SDP attributes

On 5/10/18 12:59 PM, Christer Holmberg wrote:

That's a bad example since a=bundle-only doesn't have a value.

A better example is the tls-id attribute, defined in Section 4 of

https://www.ietf.org/id/draft-ietf-mmusic-dtls-sdp-32.txt.

I'd rather prefer ( just personal preference ) the style of

https://tools.ietf.org/html/draft-ietf-mmusic-rid-14, where the

registration in section 11 refers to the grammar in section 10.

The ABNF is not according to the new style.

And, just to clarify, my comments are not based on my personal

preference, but on my understanding of how SDP attributes are to be

defined nowadays.

I've been finding that the "new" style that I have been trying to get institutionalized isn't well enough specified. I'm thinking that we need to firm it up, and preferably get that written down in 4566bis.

     Thanks,

     Paul

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