While testing interoperability with PSTN traffic from my SIP server (SS), I find situations where MGCF will send from PSTN 183 with SDP (early media), the SS handshake with PRACK normally to establish the audio path so sip user hears the early media. Later the user hears from PSTN and error announcement and SS receives an Error final response like 4xx or 5xx, at that moment the SS will also play the corresponding error message for the error received. The user hears the messages overlapped.
There is small debate if the SS should not reproduce the announcement if the far network is already sending early media. But in other cases with identical signaling except there is early media where the SS should play the error announcement to the user. Is there any guideline or standard (RFC) that covers the proper behavior in this situations? Thank you _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
