| 摘要 |
PURPOSE: A method for setting a call using an SIP-T(Session Initiation Protocol-Telephone) overlap signaling is provided to perform a call setup using an overlap signaling according to an SIP-T protocol between MGCs(Media Gateway Controllers) of origination and termination sides in an open network which provides a voice over ATM(Asynchronous Transfer Mode) service. CONSTITUTION: An origination MGC(20a) translates a termination digit in an IAM(Initial Address Message) received an origination PSTN(Public Switched Telephone Network), and connects to a termination MGC using an IP(Internet Protocol) address obtained from the translation. The origination MGC(20a) manages a call-leg about the IAM, and transmits an invite message including the corresponding IAM to the termination-side MGC(20b). The termination-side MGC(20b) connects an ATM bearer channel between an origination-side MG(Media Gateway)(10a) and a termination-side MG(10b) using session information in the invite message, and transmits the termination digit to a termination-side PSTN. In case that an SAM(Subsequent Address Message) invite message including the other termination digit is transmitted from the origination-side MGC, a previously call-leg is ended and a new call-leg is managed, and the termination digit in the SAM invite message is transmitted to the termination-side PSTN.
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