Re: [MMUSIC] SCTP AppID

[Paul Kyzivat <[e-mail]>]

On 3/14/14 3:29 AM, Christian Groves wrote:
>
> On 14/03/2014 1:25 AM, Paul Kyzivat wrote:
>> On 3/13/14 9:32 AM, Christer Holmberg wrote:
>>> Hi Christian,
>>>
>>>> Do you have an answer for the second part of the previous email?
>>>> i.e One thing I'm still missing is how you specify multiple
>>>> app/alpns (whatever we're calling them) being used in a single SCTP
>>>> association, without using datachannel?
>>>
>>> My understanding is that it is no longer possible. You can only
>>> assign *one* sctpmap attribute (e.g. indicating webrtc-datachannel)
>>> to any given SCTPoDTLS m- line.
>>
>> I never understood this question. This is describing the use of the
>> association as a whole, not not a particular channel.
> [CNG] I didn't mention channel. I am talking about the association as a
> whole. The sctpmap attribute indicates what app is in the SCTP
> association. The current syntax only allows one app. So basically I can
> run "foo" over an SCTP association natively but as soon as I want to run
> "foo" and "bar" over an SCTP association I need to use the
> webrtc-datachannel protocol.
>
> I just wanted to check that behavior was planned not just as an
> unplanned consequence of updated the draft version.

This is the problem with using the term "app" here.
*Something* must coordinate the overall use of the association. Having 
multiple things use it without coordination won't work. If you have 
multiple "applications", they could coexist by using DCEP to assign data 
channels for each application. But then DCEP, and Data Channels in 
general, is the "app" on top of SCTP. (Even then, the multiple apps need 
to agree on naming of channels in order to coexist.)

IMO what you are actually naming here is a *convention* for use of the 
association and the streams it contains.

	Thanks,
	Paul