[AVT] Sockets in multicast DTLS-SRTP

[Romain Biehlmann <[e-mail]>]

Hi all,

I hope my question is not too dumb, and not too
implementation-oriented; if so, please accept my apologies and ignore
it.

In http://tools.ietf.org/html/draft-ietf-avt-dtls-srtp-07 chapter
5.1.1, we can read the following:
"When a user of DTLS wishes to send an RTP packet in SRTP mode it
delivers it to the DTLS implementation as an ordinary application data
write (e.g., SSL_write())."

>From that, I understand that in the case of a unicast session, only
one socket is needed for the transmission of STUN, SRTP and DTLS
datagrams.
I am not sure, though, to get how it should work in the case of a (one
to many) multicast session.

Isn't the server supposed to send SRTP datagrams to a broadcast
address, whereas DTLS data must be sent directly to (unicast)
designated clients? Is the sentence in the draft only applicable to
unicast?

I thank you in advance for your valuable insight.

Romain