Device, method, program, and information provision system for telephone number research

A telephone number research method for researching a usage status of a telephone number of a telephone to be researched with a telephone number research device configured to be connected via a next-generation network (NGN) to the telephone connected to at least a destination network that is an IP multimedia subsystem (IMS) network or a voice over IP (VoIP) network, the method being characterized in comprising:

• adding a first session description protocol (SDP) parameter to an INVITE request for the telephone to be researched;
• sending the INVITE request to the destination network selected by the NGN;
• receiving a first response message from the destination network;
• and
• determining the usage status of the telephone number of the telephone based on the first response message,
• wherein
• the INVITE request does not include a signal that causes the telephone to ring for an incoming call,
• the first SDP parameter includes at least an IPv6 network protocol,
• a session border controller (SBC) has a function to convert the IPv6 network protocol to an IPv4 network protocol suitable for the destination network when the first SDP parameter is sent from the NGN to the destination network,
• the method further comprises:
• determining that the destination network is the VoIP network when the first response message is “200 OK” or the first SDP parameter has been converted, and
• determining that the destination network is the IMS network when the first SDP parameter has not been converted and the first response message includes a first error code, and
• the usage status of the telephone number indicates at least whether the telephone number is valid or invalid.

A computer program product for a telephone number research device configured to be connected via a next-generation network (NGN) to a telephone connected to at least a destination network that is an IP multimedia subsystem (IMS) network or a voice over IP (VoIP) network, the computer program product comprising a non-transitory computer-readable medium having a computer-readable program code embodied therein, the computer-readable program code causing a computer to perform at least the following:

• adding a first session description protocol (SDP) parameter to an INVITE request for the telephone to be researched, wherein the first SDP parameter includes at least an IPv6 network protocol, and the INVITE request does not include a signal that causes the telephone to ring for an incoming call;
• sending the INVITE request to the destination network selected by the NGN;
• receiving a first response message from the destination network;
• determining a usage status of a telephone number of the telephone based on the first response message, wherein the usage status of the telephone number indicates at least whether the telephone number is valid or invalid,
• determining that the destination network is the VoIP network when the first response message is “200 OK” or the first SDP parameter has been converted, and
• determining that the destination network is the IMS network when the first SDP parameter has not been converted and the first response message includes a first error code.