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

[Christer Holmberg <[e-mail]>]

Hi,

...
 
>>>> Well, in case of SCTPoDTLS one could claim that the SCTP port is not 
>>>> really part of the 4-tuple. But, if the tsvwg folks are ok to 
>>>> multiplex multiple SCTP associations using a single UDP/TCP port, 
>>>> then fine... I don't have any strong opinion - I just want to 
>>>> clarify :)
>>>> 
>>>> However, in the SCTP-SDP discussions in Honolulu it was agreed to 
>>>> only allow a single SCTP association in the case of SCTPoDTLS (even 
>>>> if draft-ietf-tsvwg-sctp-dtls-encaps allows multiple). The reason is that you would otherwise 
>>>> have multiple m- lines with the same port value (even if you don't use BUNDLE), as the port indicates the UDP/TCP port - not the SCTP port.
>>> 
>>> IMO when considering SCTPoDTLS we need to be talking about a unique 6-tuple, not a 4-tuple: 2 IP addresses, 2 UDP ports, 2 SCTP ports.
>> 
>> Perhaps it would be a good idea to add some clarification text regarding this in the draft-ietf-tsvwg-sctp-dtls-encaps.
>
> I completely disagree.
> The uniqueness SCTP rfc 4960 is referring to is the "classic" transport level 4-tuple and this respected in the sctp-dtls-encaps draft.

That's fine.

But, the fact is that each SCTP association will be transported on a single UDP/TCP 4-tuple (the SCTP port will only be used for de-multiplexing by the endpoints), and I see no harm in mentioning that.

Regards,

Christer