[jitsi-dev] SDES, ZRTP and RTP/(S)AVP


#1

Dear Ingo, developers,

The ZRTP RFC says that "ZRTP utilizes normal RTP/AVP (Audio-Visual
Profile) profiles" and "[t]he Secure RTP/AVP (SAVP) profile MAY be
used in subsequent offer/answer exchanges after a successful ZRTP
exchange has resulted in an SRTP session, or if it is known that the
other endpoint supports this profile." Does SDES utilize only RTP/SAVP
(as opposed to RTP/AVP)? I'm asking that in the context of adding the
crypto attribute to a SDP media description.

RFC 5939 "Session Description Protocol (SDP) Capability Negotiation"
allows negotiating a transport protocol from a set of supported
transport protocol using a single m= line. Jitsi currently dedicates
an m= line per supported transport protocol. Emil told me that we
should include you in the conversation about why Jitsi chooses to
default to such a behavior. For example, Emil tried to explain to me
how transport protocol negotiation with a single m= line could
potentially be problematic for Asterisk. Could we please ask you to
share your knowledge, opinion on the subject.

Best regards,
Lyubomir