Re: [MMUSIC] Single SCTP usage per SDP session?

[Paul Kyzivat <[e-mail]>]

On 12/2/14 3:22 AM, Christer Holmberg wrote:
> Hi,
>
>>>> Per my understanding, draft-ietf-tsvwg-sctp-dtls-encaps just talks about SCTP over DTLS and allowing multiple SCTP associations, which is perfectly fine.
>>>> Then it is possible to come up with SCTP-SDP semantics to use that capability.
>>>> One m= line allowing one SCTP over DTLS limit is fine. Using BUNDLE
>>>> you can replicate same 4-tuple in multiple m= lines. Then there is only one DTLS association established and multiple SCTP associations over that is possible (one per m= line).
>>>> If BUNDLE is not used then I believe same 4-tuple on multiple m=
>>>> lines are NOT possible. This is because, per my understanding, unlike TCP/native-SCTP used under non- ICE environments, in ICE-environments the TCP/UDP port specified is used both as client and server port for DTLS.
>>>
>>> Even with BUNDLE, you would have to use the same m= line port value from the beginning, which is not allowed. So, you basically would have to add the additional SCTPoDTLS m= lines once the usage of BUNDLE has been negotiated.
>>
>> bundle-only would allow you to set this up.
>
> Correct.
>
> But, then we would need to have rules saying that you are not allowed to move an m= line associated with a SCTP usage out of the BUNDLE group, etc.

How is this different from any other bundle-only m-line?