I would consider the possibility of a "three layer" approach rather than a "two layer" approach (SIP and SDP) used currently. That is, use SIP messges to carry contact information for a second-layer protocol (e.g., TCP) which is used to carry the offers and answers that describe the third layer (the protocol that carries the real data).
E.g., use SIP to carry SDP whose only importance is the address/port given for the media. The o-line gives the listening address and the m-line gives the listening port, with the m-line containing a nonstandard media type, "x-better". The recipient opens a TCP connection to the given address/port, and the two endpoints do the offer/answer negotiation via that TCP connection. (The caller may be doing several of these negotiations at the same time.) Once the endpoints have come to agreement, they use the agreed configuration to carry the real media. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
