| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a technique for allowing a client to suitably recognize the current state of a server in an IP telephone communication system. <P>SOLUTION: A pair of server devices mutually monitor changes in operation state (S1). A client device sends a first call control message for registering positional information on itself to one server device (S2). The server device having received the first call control message records the positional information (S4) and reports the positional information to the other server device (S5). The server device having been informed of the positional information transmits a second call control message instructing the client device to setting the destination of the first call control message to itself (S8) when detecting a change in the operation state of the other server device (S7). The client device, when receiving the second call control message, transmits the first call control message wherein an address indicated in the message is set (S10, S11). <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
