2011/7/5 Martin Hoffmann martin.hoffmann@telio.ch:
I think the upshot of it all is that there is no more transport=tls. If you want TLS, you have to do use the sips scheme with transport=tcp; if you want DTLS, you do sips with transport=udp.
And if you want TLS over SCTP, you must use an URI with sips schema with ;transport=sctp (rather than ;transport=tls-sctp). In fact, RFC 4168 (SCTP for SIP) defines TLS-SCTP for the Via transport (which uses TLS meaning TLS over TCP). But in case of an URI transport param, "tls-sctp" is not defined. Instead sips schema and ;transport=sctp must be used.
This would mean that the correct way to go is using sips schema.
Just a question: For now SIP-Router does not implement SCTP over TLS. Think about how will look a Record-Route when the incoming INVITE arrives via STCP over TLS.
This is somewhat consistent with SRV, where for SIP over TLS you would use the prefix _sips._tcp.
And for SCTP over TLS you would use _sips._sctp.
Cheers.