> > I'd like to clarify some facts concerning > > INVITE transactions which > > contain an early media response e.g. > > > > INV--> > > <--183 > > <--200 > > ACK--> > > > > Is it permissable/possible for the 200 > > OK to negotiate different SDP > > than the SDP negotiated in the 183? > > No, according to RFC3261 and 3264. The same > SDP should be included in the 183 and > the 200. You need another set of > offer and answer to modify session, > usually with a re-INVITE or an UPDATE. > > To consider the issue, the RFC3959 > (early disposition) and the RFC3960 > (early media) would be helpful.
I agree. However since many devices do not yet fully support the early media functionality and concepts presented within the above RFC's, it is typically wise to be forgiving of SDP changes within multiple 18x and 2xx responses when possible. This is especially true if your UAC implementation does not yet fully support interactions with a forking proxy. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
