Patent ID: 6987757

Claim:
A call setting method for a network system, the network system including a first line switching network as a line switching network on a call-out side, a first gateway connected with the first line switching network, an internet protocol (IP) packet network connected with the first gateway, second gateways respectively connected with the IP packet network, and a second line switching network as a line switching network on a call-in side connected with each of the second gateways, said method comprising: the first gateway, when a call is set between the first line switching network and the second line switching network through the IP packet network, receiving a call setting message from the first line switching network; the first gateway transmitting a call-in enable/disable inquiry message to the IP packet network to select one of the second gateways which can communicate the call setting message from the first gateway to the second line switching network, the call-in enable/disable inquiry message is received by each of the second gateways through the IP packet network; each of the second gateways when receiving the call-in enable/disable inquiry message, judging whether the second gateway itself can communicate the call setting message to the second line switching network so that each of the second gateways transmits a call-in enable/disable inquiry response message to the first gateway only when it is judged that the second gateway itself can communicate the call setting message to the second line switching network, the call-in enable/disable inquiry response message is received by the first gateway through the IP packet network; and the first gateway selecting one of the second gateways that corresponds to a source of the received call-in enable/disable inquiry response message, to transmit the call setting message to the selected second gateway.