Call control method between a packet network and PSTNs in the next generation network

摘要

The present invention relates to a call control method between a packet network and Public Switched Telephone Networks (PSTNs) in the next generation network, which enables a terminating media gateway controller to conduct the virtual Continuity (COT) check in processing ISDN User Part (ISUP) calls for the inter-operation of the packet network and the PSTNs. In particular, according to the present invention, for the inter-operation of a packet network and PSTNs, the terminating media gateway controller seizes the trunk at the time when it receives an IAM from an originating media gateway controller and transits the IAM to a terminating PSTN. At this time, the Continuity Check Indicator (CCI) code of Nature of Connection Indicators (NC) parameter within the IAM is set as ‘Continuity Check Performed on a Previous Circuit.’ When the bearer connection set-up is completed, the Continuity Indicator (CI) code of CI parameter within the COT message is set as ‘Continuity Check Successful,’ and then the COT message is transmitted to the terminating PSTN. Thus, the terminating subscriber is seized at the time when the packet network's bearer set-up has been completed. Consequently, the packet network's bearer set-up completion may be ensured. Also, by sending the IAM message at the same time as reserving the trunk between the packet network and the PSTN, to seize the trunk, the present invention may prevent the double seizure of the trunk between the packet network and the PSTN.