Re: [MMUSIC] WGLC for draft-ietf-mmusic-data-channel-sdpneg

[Flemming Andreasen <[e-mail]>]

On 2/6/16 1:44 PM, Paul Kyzivat wrote:
> On 2/4/16 10:43 PM, Christian Groves wrote:
>> Isn't this the approach we're taking today?
>> draft-ietf-mmusic-data-channel-sdpneg has general text and specific
>> drafts are used to describe protocols that use the mechanism (i.e.
>> draft-ietf-mmusic-msrp-usage-data-channel & 
>> draft-ietf-clue-datachannel).
>
> It remains to be seen if that will be enough. E.g., there currently 
> aren't any iana considerations in 
> draft-ietf-mmusic-msrp-usage-data-channel.
>
> Suppose I encounter some sdp that uses msrp over a data channel, but 
> that usage is unknown to me. How do I find the spec (the reference to 
> draft-ietf-mmusic-msrp-usage-data-channel) that defines that usage?
>
> I would like to think that the iana registries will allow me to trace 
> back to the relevant specs.
>
No disagreement on that part, however having taken another look at both 
sdpneg and the msrp-usage documents, I still don't agree with your 
original request for all (existing and new) attributes to specify how 
they may or may not be used with the dcsa attribute defined by sdpneg.

As Christian noted, the sub-protocol specifics are defined in individual 
documents (like msrp-usage), which calls your the parameters that are at 
least needed to be supported for that usage. Taking MSRP as an example, 
why isn't that enough, and how do you see the resulting set of 
attributes that may or may not be used with MSRP differ between use in a 
data-channel (and hence encapsulated in dcsa) or as a regular media 
stream ?

Also, it would be good to hear from more people on this, including the 
document authors.

Thanks

-- Flemming


>     Thanks,
>     Paul
>
>> Regards, Christian
>>
>> On 4/02/2016 3:58 PM, Paul Kyzivat wrote:
>>> On 2/3/16 5:42 PM, Flemming Andreasen wrote:
>>>
>>>> I'm not concerned about the IANA part. I agree that *if* we need to
>>>> expliclty specify attribute interactions for "dcsa", then it should be
>>>> part of the IANA registry. What I am not agreeing with at this 
>>>> point is
>>>> that there is indeed a need to explicitly speficy these 
>>>> interactions as
>>>> opposed to relying on a more general algorithmic approach (plus the
>>>> offerer being responsible for generating a valid offer if he wants to
>>>> establish a data channel).
>>>
>>> Well, an obvious one is that the protocol(s) the attribute pertains to
>>> need to be defined to work over data channels.
>>>
>>>     Thanks,
>>>     Paul
>>>
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