Telephone number investigation device, investigation method, investigation program, and information provision system

Abstract

This makes it possible to efficiently determine the usage status of the telephone numbers being surveyed. [Solution] The telephone number investigation device 10 is connected to a plurality of IP telephone terminals 50 connected to the incoming fixed IMS network 30 via the outgoing fixed IMS network 20. The device sends an INVITE request to the IP telephone terminal 50 to be investigated, adding SDP parameters to the INVITE request, and receives a response message via the outgoing fixed IMS network 20. The device determines the usage status of the telephone number of the IP telephone terminal 50 to be investigated based on the elapsed time until a response of code 404 Not Found is received.

Description

Technical Field

[0001] The present invention relates to a telephone number investigation device, an investigation method, an investigation program, and an information providing system.

Background Art

[0002] As a conventional technique related to the determination of telephone number information, there is a telephone number information determination device using a computer server connected to a plurality of terminals via an Internet network, which includes a database for storing usage history information of a plurality of telephone numbers, and a search information reception means for receiving authentication information from a terminal and receiving a telephone number as search information from the terminal on condition that an authentication means permits login, and a system control means for searching the database using the telephone number received by the search information reception means, analyzing whether there are a plurality of histories in the telephone number history information that transition from an active state to a missing number state or analyzing a missing number change in the field of the telephone number, and / or analyzing whether there are a plurality of histories in the telephone number history information that transition from a missing number state to an active state or analyzing a valid change in the field of the telephone number, referring to the unaccumulated history of the telephone number history information, the most recent investigation record of the telephone number history information being a missing number history, the investigation record one before the most recent investigation record being a missing number history, and a plurality of call stop histories existing in the telephone number history information, generating history determination information for determining a predetermined subscriber number for the telephone number of the search information, and displaying this history determination information to the terminal via the Internet network. There is known a telephone number information determination device provided with such means (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] Incidentally, with the transition from PSTN (Public Switched Telephone Networks) to NGN (Next Generation Network), the interoperator interconnection interface will also change from the common channel signaling system SS7 (Signaling System No. 7) to the IP (Internet Protocol) system SIP (Session Initiation Protocol). As a result, SIP-based messages from originating terminals (for example, survey devices that investigate telephone number usage) will reach the IMS (IP Multimedia Subsystem) network, the NGN network, and the IP telephone network (VoIP: Voice over Internet Protocol).

[0005] IMS is a standard for realizing integrated multimedia services by IP-based services that were previously provided on fixed networks and mobile communications. Mobile communication systems and NGNs are systems built in accordance with this standard.

[0006] Therefore, it is necessary to use IMS interconnection interfaces for inter-carrier interconnection, etc., to determine the usage status of telephone numbers in the receiving IMS network, and to introduce a SIP protocol-based telephone number lookup tool that can connect to the originating IMS network via UNI (User Network Interface) to ensure a smooth transition to the new system infrastructure. [Overview of the project] [Problems that the invention aims to solve]

[0007] According to the prior art described above, it is possible to determine the usage status of telephone numbers in the IMS network by using an IMS interconnection interface for inter-carrier interconnection, and to determine whether a telephone number is valid (exists) in the IMS network. However, in the prior art, if the response message from the receiving end is code 404 Not Found, it is determined that the telephone number of the IP phone terminal under investigation is unavailable. However, it has been found that there are cases where the number actually exists, and it has been found that the determination of the existence or unavailable (status) of an IP phone terminal may yield results that differ from reality.

[0008] If it is unclear whether a number exists or is unavailable, one possible method is to dial the number, receive a code, and then check the response message to determine whether it exists or is unavailable. However, if voice guidance analysis is performed for all phone numbers determined to be unavailable based on the response code, it would be extremely inefficient to perform usage status checks and analyze the voice guidance for all of these phone numbers.

[0009] Therefore, the present invention aims to provide a telephone number survey device, survey method, survey program, and telephone number information provision system that enable efficient determination of the usage status of telephone numbers under survey. [Means for solving the problem]

[0010] To solve the above problems, according to the present invention, Includes SIP server Multiple IP phone terminals connected to the receiving fixed IMS network Includes SIP serverA telephone number lookup device connected via an outgoing fixed IMS network, comprising: a message exchange control unit that adds SDP parameters to an INVITE request to the IP telephone terminal to be looked up and sends the INVITE request to the incoming fixed IMS network and receives a response message from the incoming fixed IMS network; and a telephone number lookup determination unit that determines the usage status of the telephone number of the IP telephone terminal to be looked up according to the response message, wherein the SDP parameters are described as: network protocol is IPv4, media type is audio only, media transport protocol is RTP / AVP only, and voice codecs include G.711μ-law and G.722, and the telephone number lookup determination unit determines that the telephone number of the IP telephone terminal to be looked up exists if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, and if the response message is code 404 Not Found, After sending the aforementioned INVITE request, the response is: US Code 404 Not Found Response message The elapsed time until reception is To determine whether the incoming call is rejected by a private network connected to the aforementioned fixed IMS network, and the response from the private network is long because it is the source of a code 404 Not Found error, or whether the IP phone terminal actually exists but is set to outgoing-only mode, and the response from the IP phone terminal is long because it is the source of a code 404 Not Found error, If the predetermined standard time is exceeded, it is determined that the telephone number of the IP phone terminal linked to the aforementioned telephone number under investigation actually exists, and the elapsed time is The aforementioned If the specified standard time is not exceeded, a telephone number investigation device is provided that determines whether the telephone number of the IP phone terminal under investigation is either missing or existing.

[0011] In addition to the above configuration, it is preferable to include a voice conversion unit, and based on the IP phone terminal associated with the telephone number under investigation that is determined to be either missing or existing, a list of telephone numbers is created by excluding the telephone numbers of terminals whose IP phone terminal telephone numbers are determined to be existing from the list of telephone numbers under investigation. Based on the telephone number list, the message exchange control unit and the telephone number investigation and determination unit are executed to determine the usage status of the telephone number of the IP phone terminal under investigation, an audio file is extracted from the voice guidance after receiving the code 404 Not Found response, and text data is created based on the audio file, and based on the text data, it is preferable to determine whether the IP phone terminal under investigation is either missing or existing.

[0012] Furthermore, according to the present invention, Includes SIP server Multiple IP phone terminals connected to the receiving fixed IMS network Includes SIP server A method for investigating telephone numbers, which uses a device connected via a dispatching fixed IMS network to investigate the usage status of a telephone number of an IP telephone terminal to be investigated, comprising: a transmission step of sending an INVITE request to the IP telephone terminal to be investigated to the receiving fixed IMS network with SDP parameters attached to the INVITE request; a reception step of receiving a response message from the receiving fixed IMS network; and a determination step of determining the usage status of the telephone number of the IP telephone terminal to be investigated according to the response message, wherein the SDP parameters are IPv4 for the network protocol, audio only for the media type, RTP / AVP only for the media transport protocol, and G.711 μ-law and G.722 for the audio codecs, and in the determination step, if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, it is determined that the telephone number of the IP telephone terminal to be investigated is real. If the above response message is code 404 Not Found, After sending the aforementioned INVITE request, as a response US Code 404 Not Found Response message The elapsed time until reception is To determine whether the incoming call is rejected by a private network connected to the aforementioned fixed IMS network, and the response from the private network is long because it is the source of a code 404 Not Found error, or whether the IP phone terminal actually exists but is set to outgoing-only mode, and the response from the IP phone terminal is long because it is the source of a code 404 Not Found error, If the predetermined standard time is exceeded, it is determined that the telephone number of the IP phone terminal linked to the aforementioned telephone number under investigation actually exists, and the elapsed time is The aforementioned A method for investigating telephone numbers is provided, characterized in that if a predetermined standard time is not exceeded, it is determined that the telephone number of the IP phone terminal under investigation is either missing or actually exists.

[0013] The method for investigating telephone numbers preferably includes, in addition to the above configuration, a voice conversion step, wherein the determination step creates a list of telephone numbers by excluding from the investigation telephone numbers that have been determined to be the telephone numbers of the IP telephone terminals associated with the investigation telephone numbers that have been determined to be either missing or existing, the transmission step and the reception step and the determination step are executed based on the telephone number list to determine the usage status of the telephone number of the investigation IP telephone terminal, and the voice conversion step is executed from the voice guidance after receiving the code 404 Not Found response to extract an audio file and create text data based on the audio file, and it is preferable to determine based on the text data whether the investigation IP telephone terminal is either missing or existing.

[0014] Furthermore, according to the present invention, Includes SIP server Multiple IP phone terminals connected to the receiving fixed IMS network Includes SIP serverThe following processes are performed on a computer connected via a dispatching fixed IMS network: a transmission process that adds SDP parameters to an INVITE request to the IP phone terminal under investigation and sends the INVITE request to the receiving fixed IMS network; a reception process that receives a response message from the receiving fixed IMS network; and a determination process that determines the usage status of the telephone number of the IP phone terminal under investigation based on the response message, wherein the SDP parameters are set to IPv4 for the network protocol, audio only for the media type, RTP / AVP only for the media transport protocol, and G.711 μ-law and G.722 for the audio codecs; and the determination process determines that the telephone number of the IP phone terminal under investigation exists if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here; and if the response message is code 404 Not Found, After sending the aforementioned INVITE request, as a response US Code 404 Not Found Response message The elapsed time until reception is To determine whether the incoming call is rejected by a private network connected to the aforementioned fixed IMS network, and the response from the private network is long because it is the source of a code 404 Not Found error, or whether the IP phone terminal actually exists but is set to outgoing-only mode, and the response from the IP phone terminal is long because it is the source of a code 404 Not Found error, If the predetermined standard time is exceeded, it is determined that the telephone number of the IP phone terminal linked to the aforementioned telephone number under investigation actually exists, and the elapsed time is The aforementioned A telephone number investigation program is provided, characterized in that, if the predetermined standard time is not exceeded, it performs a process to determine whether the telephone number of the IP phone terminal under investigation is either missing or existing.

[0015] In addition to the above configuration, the investigation program includes a voice conversion processing unit. The determination process creates a telephone number list excluding the telephone number of the terminal determined to be the telephone number of the IP telephone terminal from the investigation targets based on the telephone number of the investigation target for which it is determined that the IP telephone terminal linked to the telephone number of the investigation target is either missing or existent. Based on the telephone number list, the transmission process, the reception process, and the determination process are executed to determine the usage status of the telephone number of the IP telephone terminal of the investigation target. After receiving the response of "404 Not Found", voice guidance is received, and the voice conversion processing unit extracts a voice file and creates text data based on the voice file. Based on the text data, it is preferable to determine whether the IP telephone terminal of the investigation target is either missing or existent.

[0016] Further, according to the present invention, there is provided a telephone number information providing system having the above-described telephone number investigation device and a user terminal. When the telephone number investigation device receives a request for providing telephone number investigation information about the IP telephone terminal from the user terminal, the system includes a network interface unit that transmits, via the IP network, the usage status of the telephone number of the IP telephone terminal determined by the telephone number investigation determination unit to the user terminal that made the request for providing telephone number investigation information.

Effects of the Invention

[0017] According to the present invention, in one aspect, when the response message from the receiving side is "404 Not Found", it becomes possible to efficiently determine whether the usage status of the telephone number of the investigation target is existent or missing.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram showing a network connection form of a telephone number investigation device according to an embodiment of the present invention. [Figure 2]This is a diagram for explaining the basic sequence of operations when a landline phone exists as an incoming device and is not in use between the originating fixed IMS network and the terminating fixed IMS network. [Figure 3] This is a diagram for explaining the basic sequence of operations when a landline phone exists as an incoming device and is in use between the originating fixed IMS network and the terminating fixed IMS network. [Figure 4] This is a diagram for explaining the basic sequence of operations when the incoming device has a missing number between the originating fixed IMS network and the terminating fixed IMS network. [Figure 5] This is a diagram for explaining the basic sequence of operations when the incoming device is in a transferred state between the originating fixed IMS network and the terminating fixed IMS network. [Figure 6] This is a block diagram showing the configuration of the phone number investigation device in FIG. 1. [Figure 7] This is a diagram for explaining Pattern 1 of the operation sequence when a landline phone exists as the IP phone terminal to be investigated and is not in use. [Figure 8] This is a diagram for explaining Pattern 2 of the operation sequence when a landline phone exists as the IP phone terminal to be investigated and is not in use. [Figure 9] [[ID=二十一]]This is a diagram for explaining Pattern 3 of the operation sequence when a landline phone exists as the IP phone terminal to be investigated and is not in use. [Figure 10] This is a diagram for explaining the operation sequence when a landline phone exists as the IP phone terminal to be investigated and is in use. [Figure 11] This is a diagram for explaining receiving a 404 error when there is no specific user associated with the phone number and the phone number is not registered in the SIP server (missing number). [Figure 12] This is a diagram for explaining receiving a 404 error when the private network (PBX) housed in the terminating fixed IMS network rejects the incoming call and uses the response from the private network as the generation source (existing). [Figure 13]This diagram illustrates how a 404 error can be received when an IP phone terminal is configured for outgoing calls only and the response is generated from the IP phone terminal (which is a real-world scenario). [Figure 14] This is a flowchart of this embodiment, which is executed when the response message from the receiving fixed IMS network is code 404 Not Found. [Figure 15] This diagram illustrates the sequence of actions when the response message from the receiving fixed IMS network is code 404 Not Found. [Figure 16] This diagram illustrates the operation sequence when the IP phone terminal being investigated has a missing number (IPv4, G.711 μ-law only). [Figure 17] This diagram illustrates the sequence of operations when the IP phone terminal under investigation is relocated. [Figure 18] This diagram shows a summary of the methods for investigating the usage status of telephone numbers on IP phone terminals. [Figure 19] This is a system configuration diagram of a telephone number information provision system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0019] Hereinafter, embodiments relating to a telephone number investigation device, a telephone number investigation method, a telephone number investigation program, and a telephone number information provision system configured based on the present invention will be described with reference to the attached drawings.

[0020] The following shows a specific configuration of the telephone number investigation device according to the present invention. The telephone number search device according to the present invention is a telephone number search device connected to a plurality of IP telephone terminals connected to a receiving fixed IMS network via a sending fixed IMS network, and comprises a message exchange control unit that adds SDP parameters to an INVITE request to the IP telephone terminal to be searched and sends the INVITE request to the receiving fixed IMS network and receives a response message from the receiving fixed IMS network, and a telephone number search determination unit that determines the usage status of the telephone number of the IP telephone terminal to be searched according to the response message, wherein the SDP parameters are described as network protocol being IPv4, media type being audio only, media transport protocol being RTP / AVP only, and voice codecs including G.711μ-law and G.722, and the telephone number search determination unit determines that the telephone number of the IP telephone terminal to be searched exists if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, and if the response message is code 404 Not Found, then the code 404 Not The configuration includes a setting that determines if the time elapsed until a Found response is received exceeds a predetermined standard time, that the telephone number of the IP phone terminal associated with the telephone number under investigation is real, and if the elapsed time does not exceed the predetermined standard time, that the telephone number of the IP phone terminal under investigation is either missing or real. Other configurations are arbitrarily set and are not limited to the configurations shown below.

[0021] (Network connection configuration) Figure 1 is a schematic diagram showing the network connection configuration of a telephone number investigation device 10 according to an embodiment, as an example of a specific configuration of the telephone number investigation device according to the present invention.

[0022] In this embodiment, the telephone number investigation device 10 is connected to a plurality of fixed telephone terminals (specifically, IP telephone terminals 50a, 50b, 50c) that are the target of investigation and are connected to the incoming fixed IMS network 30 (specifically, for example, an IP telephone network (VoIP: Voice over Internet Protocol)) via the outgoing fixed IMS network 20 (specifically, for example, an NGN network). In the description of this embodiment, when it is not necessary to distinguish between each of the IP telephone terminals 50a, 50b, 50c, etc. for each network (in other words, each contracting carrier), they will simply be referred to as "IP telephone terminal 50".

[0023] The originating fixed IMS network 20 is equipped with a SIP server 20a, and the operation of the originating fixed IMS network 20 is managed and controlled by the SIP server 20a. The receiving fixed IMS network 30 is equipped with SIP servers 30a, 30b, and 30c, and the operation of the receiving fixed IMS network 30 is managed and controlled by the SIP servers 30a, 30b, and 30c.

[0024] The receiving fixed IMS network 30 is constructed for each telecommunications carrier (in the example shown in Figure 1, carriers A, B, and C), and IP phone terminals 50a, 50b, and 50c are connected to each network (in other words, each contracted carrier) via SIP servers 30a, 30b, and 30c managed and operated by each carrier.

[0025] The receiving fixed IMS network 30 supports the IP (Internet Protocol) v4 network protocol (in other words, Internet Protocol, IP version) for SDP (Session Description Protocol) parameters, supports audio as the media type, supports RTP / AVP as the media transport protocol, and supports the G.711 μ-law audio codec.

[0026] Assuming a landline phone with a 0ABJ-type telephone number, we will consider an IP phone terminal 50 connected to the receiving network, which is the receiving fixed IMS network 30.

[0027] In the configuration shown in Figure 1, the outgoing device, the telephone number lookup device 10, dials (makes a call) the telephone numbers of the IP telephone terminals 50a, 50b, and 50c connected to the incoming fixed IMS network 30 as the telephone numbers of the incoming telephone terminals. This results in routing being performed in the following order: SIP server 20a in the outgoing fixed IMS network 20, outgoing IBCF (Inter-connection Border Control Function) 21, incoming IBCF 31, SIP servers 30a, 30b, and 30c, and finally the incoming IP telephone terminals 50a, 50b, and 50c.

[0028] At this time, a UNI connection is guaranteed between the telephone number lookup device 10 and the outgoing fixed IMS network 20, and inter-carrier interconnection between the outgoing fixed IMS network 20 and the receiving fixed IMS network 30 is guaranteed via IMS interconnection interfaces (specifically, the outgoing IBCF21 and the receiving IBCF31), and a specific SIP message (details to be described later) transmitted from the telephone number lookup device 10 in accordance with the SIP signaling scheme reaches the receiving fixed IMS network 30.

[0029] In the example shown in Figure 1, the II-NNI (Network-Network Interface), which is a common interface for interconnection between IMS operators via IP-IP connections, is defined in TTC standard JJ-90.30 (TTC: Telecommunication Technology Committee).

[0030] Incidentally, according to SIP, in order to perform real-time communication, it is necessary for terminals to negotiate the encoding method of packets containing media information and the address of the packet's destination. The description language required for this negotiation is called SDP (Session Description Protocol), which is defined in the TTC standard RFC4566.

[0031] To establish a SIP session, the sender first sends a request containing media information in a SIP message, and the receiver replies with a response selecting an available media from that request, thereby sharing the media information to be used for communication between the sender and receiver.

[0032] Sending a SIP message containing media information to initiate a session is called an offer, and responding with available media information is called an answer. This offer / answer model is defined in the TTC standard RFC3264. Furthermore, the SDP media negotiation procedure in IMS is specified in the TTC standard JJ-90.26.

[0033] In the example shown in Figure 1, the telephone number investigation device 10 sends an INVITE method SDP offer (referred to as an "INVITE request") to the IP telephone terminal 50 to be investigated via the outgoing fixed IMS network 20 (including SIP server 20a) and the incoming fixed IMS network 30 (including SIP servers 30a, 30b, and 30c), adding (in other words, describing) predetermined SDP parameters (referred to as "determination SDP parameters") to the SDP parameters before sending.

[0034] The SDP parameters used for determination, which are added to the SDP parameters when sending an INVITE request, are the network protocol (in other words, the Internet Protocol, IP version), media type, media transport protocol, and audio codec.

[0035] In response to an INVITE request, the receiving IP phone terminal 50 compares the SDP parameters included in the INVITE request with the SDP parameters it has available, and sends back a response message with a predetermined code in the SIP session, depending on the result of the comparison (i.e., whether the SDP parameters match or not).

[0036] The telephone number investigation device 10 then determines, based on the response of the received predetermined code, whether the receiving IP phone terminal 50 is present or absent (and consequently, whether the telephone number of the IP phone terminal 50 is present or missing).

[0037] (Basic sequence) Figures 2 to 5 illustrate the basic sequence of operations between the originating fixed IMS network 20 and the receiving fixed IMS network 30 when the IP telephone terminal 50, acting as the receiving device, is a fixed telephone, using the INVITE method in IMS interconnection. Note that the basic sequence of operations between the originating device (specifically, the telephone number lookup device 10) and the IP telephone terminal 50, which is a fixed telephone, is not limited to what is shown in Figures 2 to 5, but may follow, for example, the specifications in TTC standards JJ-90.30, JJ-90.26, and TR-1088.

[0038] Communication between the originating device and the receiving device takes place via the originating fixed IMS network 20, the originating IBCF 21, the receiving IBCF 31, and the receiving fixed IMS network 30. Figures 2 to 5 show the basic sequence of operations between the originating device and the receiving device (specifically, the IP telephone terminal 50), focusing on the content of communication between the originating fixed IMS network 20 (in particular, SIP server 20a) and the receiving fixed IMS network 30 (in particular, SIP servers 30a, 30b, 30c).

[0039] (If it actually exists) Figure 2 illustrates the basic sequence of operations in an IMS interconnection using the INVITE method, when a fixed telephone (specifically, an IP phone terminal 50) exists as the receiving device, is not busy, and the calling device disconnects the communication.

[0040] The originating device sends an INVITE request to the receiving device via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the receiving device's service provider (F1).

[0041] In response, the receiving fixed IMS network 30 sends back a code 100 Trying response (F2) to the sending fixed IMS network 20, indicating that the request has been received in the SIP session, and a ringtone is sent, along with a code 180 indicating that the ringtone is sounding in the SIP session. A ringing response is returned (F3). At this time, the receiving device rings.

[0042] Next, a Provisional Response Acknowledgement (PRACK) request, which is a provisional response confirmation in a SIP session, is sent from the originating fixed IMS network 20 to the receiving fixed IMS network 30 (F4).

[0043] In response, the receiving fixed IMS network 30 sends a code 200 OK response (F5) back to the sending fixed IMS network 20, indicating that the request (specifically, a PRACK (Provisional Response Acknowledgement) request) in the SIP session was successfully processed.

[0044] Next, the receiving fixed IMS network 30 sends a code 200 OK response (F6) back to the sending fixed IMS network 20, indicating that the request (specifically, the INVITE request) in the SIP session was successfully processed.

[0045] In response, the originating fixed IMS network 20 sends an ACK (Acknowledgment) response to the receiving fixed IMS network 30, indicating acknowledgment in the SIP session (F7), and a session is established between the originating device and the receiving device, and communication begins.

[0046] While communication is taking place between the sending device and the receiving device, if necessary, an UPDATE request is sent from the sending fixed IMS network 20 to the receiving fixed IMS network 30 to request an update of data / information in the SIP session (F8). In response, the receiving fixed IMS network 30 sends back a code 200 OK response to the sending fixed IMS network 20, indicating that the request (specifically, the UPDATE request) in the SIP session has been successfully processed (F9).

[0047] Subsequently, (in the example shown in Figure 2, when the originating device disconnects the communication) a BYE request is sent from the originating fixed IMS network 20 to the receiving fixed IMS network 30 to indicate the termination of the SIP session (F10). In response, (in the example shown in Figure 2) a code 200 OK response is sent back from the receiving fixed IMS network 20 to the originating fixed IMS network 20 to indicate that the request (specifically, the BYE request) in the SIP session was successfully processed (F11). As a result, the session between the originating device and the receiving device is terminated, that is, communication between the originating device and the receiving device is disconnected.

[0048] (If the conversation is ongoing) Figure 3 illustrates the basic sequence of operations when a fixed telephone (specifically, an IP phone terminal 50) exists and is busy as the receiving device, in the INVITE method of IMS interconnection between the originating fixed IMS network 20 and the receiving fixed IMS network 30. This basic sequence is specified in the TTC standard TR-1088.

[0049] The originating device sends an INVITE request to the receiving device via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the receiving device's service provider (F1).

[0050] In response, the receiving fixed IMS network 30 sends back a code 100 Trying response (F2) indicating that it has received the request in the SIP session, and a code 486 Busy Here response (F3) indicating that the media resource requested by the sender in the SIP session is currently busy and the session cannot be started.

[0051] In response, the originating fixed IMS network 20 sends an ACK (Acknowledgment) response to the receiving fixed IMS network 30, indicating acknowledgment in the SIP session (F4). This terminates the session related to the INVITE request from the originating device.

[0052] (In the case of missing numbers (including those that actually exist)) Figure 4 illustrates the basic sequence of operations when the receiving device (in other words, the telephone number) is missing (in reality, this also includes cases where the number actually exists; this will be explained in detail later) when the INVITE method is used in an IMS interconnection between the originating fixed IMS network 20 and the receiving fixed IMS network 30. This basic sequence is specified in the TTC standard TR-1088.

[0053] The originating device sends an INVITE request to the receiving device via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the receiving device's service provider (F1).

[0054] In response, the receiving fixed IMS network 30 sends back a code 100 Trying response (F2) indicating that it has received the request in the SIP session, and a code 404 Not Found response (F3) indicating that the media resource requested by the sender in the SIP session could not be found.

[0055] In response, the originating fixed IMS network 20 sends an ACK (Acknowledgment) response to the receiving fixed IMS network 30, indicating acknowledgment in the SIP session (F4). This terminates the session related to the INVITE request from the originating device.

[0056] (In case of relocation) Figure 5 illustrates the basic sequence of operations when a fixed telephone (specifically, an IP phone terminal 50) is transferred between the originating fixed IMS network 20 and the receiving fixed IMS network 30 using the INVITE method in an IMS interconnection. This basic sequence is specified in the TTC standard TR-1088.

[0057] The originating device sends an INVITE request to the receiving device via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the receiving device's service provider (F1).

[0058] In response, the receiving fixed IMS network 30 sends back a code 100 Trying response (F2) indicating that the request has been received in the SIP session, and a code 183 Session Progress response (F3) indicating the progress of the call in the SIP session.

[0059] Furthermore, a relocation guidance message informing the recipient that the telephone number of the receiving device has changed, along with the new telephone number (in other words, a relocation guidance message informing the recipient that the receiving device has moved, along with the new telephone number), is transmitted from the receiving fixed IMS network 30 to the sending fixed IMS network 20 as RTP (Real-time Transport Protocol). The duration of the relocation guidance message is, for example, about 60 to 80 seconds.

[0060] After the transfer guidance is complete, the receiving fixed IMS network 30 sends a code 410 Gone response (F4) to the sending fixed IMS network 20, indicating that the media resource requested by the sender in the SIP session previously existed but no longer does.

[0061] In response, the originating fixed IMS network 20 sends an ACK (Acknowledgment) response to the receiving fixed IMS network 30, indicating acknowledgment in the SIP session (F5). This terminates the session related to the INVITE request from the originating device.

[0062] (Telephone number lookup device) Figure 6 is a block diagram showing the configuration of the telephone number lookup device 10 according to the embodiment.

[0063] The telephone number investigation device 10 according to this embodiment is connected to a plurality of IP telephone terminals 50 connected to the incoming fixed IMS network 30 via the outgoing fixed IMS network 20. The device sends an INVITE request to the IP telephone terminal 50 to be investigated (directed towards the IP telephone terminal 50) by adding SDP parameters to the INVITE request, and receives a response message from the incoming fixed IMS network 30. The device then determines the telephone number usage status of the IP telephone terminal 50 to be investigated based on the response message.

[0064] The telephone number lookup device 10 includes a network interface unit 11, a message exchange control unit 12, a telephone number lookup and determination unit 13, a telephone number history generation unit 14, a telephone number history database (DB) 15, and a voice conversion unit 16.

[0065] The network interface unit 11 serves as the communication interface for the telephone number lookup device 10 to perform communication compliant with the SIP protocol.

[0066] The message exchange control unit 12 sends an INVITE request containing determination SDP parameters to the IP phone terminal 50 under investigation, and also receives a message (for example, a response of a predetermined code in a SIP session) from the receiving fixed IMS network 30 (in particular, SIP servers 30a, 30b, 30c).

[0067] The telephone number investigation and determination unit 13 determines whether the IP phone terminal 50 to be investigated on the receiving end actually exists, in response to a message received via the message exchange control unit 12 (for example, a response of a predetermined code in a SIP session), and ultimately determines the validity of the telephone number of the IP phone terminal 50 to be investigated (in other words, the usage status of the telephone number).

[0068] The telephone number history generation unit 14 constructs a telephone number history database 15 by assigning a timestamp indicating the date and time of determination to each of the determination results from the telephone number investigation and determination unit 13 and recording them chronologically on a recording medium.

[0069] The data structure (in other words, the data items included) of the telephone number history database 15 is not limited to a specific structure or items, but the telephone number history information stored in the telephone number history database 15 may include, for example, a combination of the "telephone number" being investigated, the "error code" returned from the receiving fixed IMS network 30, the "investigation date" (i.e., timestamp), the "determination result of existence / missing / transferred," and "other layer information" related to the layer returned from the receiving fixed IMS network 30, for each investigation (in other words, each time an INVITE request is sent).

[0070] The telephone number history information stored in the telephone number history database 15 may also include, in addition to the data items described above, the type of IP phone terminal 50 being investigated, the "new subscriber number" which is the destination or contact telephone number identified during the investigation, the "company name / individual name" of the telephone number owner, "attribute information" such as address and age, "map link information," and "credit information" for evaluating creditworthiness.

[0071] Then, for example, when the telephone number investigation device 10 investigates the usage status of the telephone number "03-XXXX-XXXX", the investigation information is sequentially recorded in the telephone number history database 15 for each determination made by the telephone number investigation and determination unit 13, and stored as telephone number history information.

[0072] The telephone number history database 15 may be implemented on a large-capacity recording medium such as semiconductor memory, hard disk, or optical memory such as a DVD (Digital Versatile Disc).

[0073] The voice conversion unit 16 will be explained later.

[0074] The telephone number lookup device 10 is configured to include a microprocessor with a built-in memory (not shown) on which a predetermined program (including the telephone number lookup program according to the embodiment) is recorded, or a microprocessor with an externally attached memory (not shown) on which a predetermined program is recorded, and an LSI (Large Scale Integration) that performs peripheral control, including communication control.

[0075] Then, the microprocessor sequentially reads and executes a predetermined program (including the telephone number search program according to this embodiment) recorded in memory (not shown), thereby configuring the network interface unit 11, message exchange control unit 12, telephone number search determination unit 13, and telephone number history generation unit 14, and realizing the predetermined functions of the telephone number search device 10.

[0076] (How to find a phone number) As an example of a specific configuration of the telephone number investigation method according to the present invention, the telephone number investigation method according to the embodiment is a method for investigating the telephone number usage status of a plurality of IP telephone terminals 50 connected to a receiving fixed IMS network 30 using a computer (specifically, a telephone number investigation device 10) connected via a sending fixed IMS network 20, and includes the steps of: sending an INVITE request to the IP telephone terminal 50 (directed towards the IP telephone terminal 50) with SDP parameters attached to the INVITE request to the IP telephone terminal 50 to be investigated; receiving a response message from the receiving fixed IMS network 30; and determining the telephone number usage status of the IP telephone terminal 50 to be investigated according to the response message, wherein the SDP parameters are set to IPv4 for the network protocol, audio only for the media type, RTP / AVP only for the media transport protocol, and G.711 μ-law and G.722 for the audio codecs.

[0077] The telephone number investigation method described below can be carried out, for example, by running a telephone number investigation program on a computer (specifically, a telephone number investigation device 10) and executing the corresponding steps according to the investigation program.

[0078] As SDP parameters, the network protocol (in other words, the Internet Protocol, IP version) among the SDP parameters for determination is described using IPv4, and the other SDP parameters for determination are described as follows. The following description of the SDP parameters for determination is referred to as "SDP for IPv4". ○Media type: audio only ○Media transport protocol: RTP / AVP only ○Audio codecs: G.711 μ-law and G.722

[0079] (Existence Determination / Part 1) Figure 7 illustrates Pattern 1 of the operation sequence when IPv4 is described as the network protocol in the SDP parameters and the above IPv4 SDP is described as the determination SDP parameters, and when a fixed-line telephone exists as the IP telephone terminal 50 under investigation but is not currently on call.

[0080] The message exchange control unit 12 of the telephone number investigation device 10 sends an INVITE request to the IP telephone terminal 50 to be investigated via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the IP telephone terminal 50's subscriber. (F1) At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request.

[0081] In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20, indicating that the request has been received in the SIP session (F2). At the same time, a ringtone is sent, and a code 180 Ringing response (F3) is sent back, indicating that the phone is ringing in the SIP session. At this time, the incoming IP phone terminal 50 to be investigated rings.

[0082] In this case, the telephone number investigation and determination unit 13 of the telephone number investigation device 10 determines that a landline phone actually exists as the IP phone terminal 50 to be investigated on the receiving end and that it is not busy (i.e., the telephone number of the IP phone terminal 50 to be investigated actually exists).

[0083] Next, the message exchange control unit 12 of the telephone number lookup device 10 sends a CANCEL request, which is an instruction to terminate the SIP session, to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F4).

[0084] The message exchange control unit 12 of the telephone number investigation device 10, upon receiving a code 180 Ringing response, immediately (or more precisely, almost simultaneously with the receipt of the code 180 Ringing response) sends a CANCEL request to stop the ringing of the incoming IP phone terminal 50 being investigated. As a result, the ringing of the incoming IP phone terminal 50 being investigated is either not present or stops after a very short time.

[0085] In response to a CANCEL request from the originating device (specifically, the telephone number lookup device 10), the receiving fixed IMS network 30 sends a code 200 OK response (F5) to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the originating fixed IMS network 20, indicating that the request (specifically, the CANCEL request) was processed successfully in the SIP session. At the same time, a code 487 Request Terminated response (F6) is sent back, indicating that the SIP session has ended.

[0086] In response, the message exchange control unit 12 of the telephone number lookup device 10 sends an ACK (Acknowledgment) response, indicating acknowledgment in the SIP session, to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F7). This terminates the session between the telephone number lookup device 10 and the IP phone terminal 50 being looked up on the receiving end, meaning that communication between the telephone number lookup device 10 and the IP phone terminal 50 being looked up is disconnected. If the status of the IP phone terminal 50 being looked up changes due to the operation sequence shown in Figure 7, the information in the telephone number history database 15 is updated.

[0087] (Existence Determination / Part 2) In the basic sequence of operations between the originating fixed IMS network 20 and the receiving fixed IMS network 30 using the INVITE method in IMS interconnection, if a fixed telephone exists as the receiving device and is not busy, the normal sequence of operations is that a code 100 Trying response is returned in response to the INVITE request from the originating device, followed by a code 180 Ringing response.

[0088] However, according to the inventors' verification, depending on the IP phone terminal 50's service provider, there are irregular cases where, in response to an INVITE request from the calling device, if a landline phone actually exists as the receiving device and is not busy, a code 100 Trying response is followed by a code 183 Session Progress response or a code 200 OK response.

[0089] Therefore, even if the telephone number investigation unit 13 of the telephone number investigation device 10 receives a code 183 Session Progress response or a code 200 OK response without receiving a code 180 Ringing response (F3 in Figure 7), it determines that a landline phone actually exists and is not busy as the IP phone terminal 50 being investigated on the receiving end (i.e., the telephone number of the IP phone terminal 50 being investigated actually exists). In this way, the status of the IP phone terminal 50 being investigated is determined by the operation sequence shown in Figure 7, and if there is a change in that status, the information in the telephone number history database 15 is updated.

[0090] Figure 8 illustrates Pattern 2 of the operation sequence when IPv4 is described as the network protocol in the SDP parameters and the above IPv4 SDP is described as the determination SDP parameters, and when a fixed-line telephone exists as the IP telephone terminal 50 under investigation but is not currently on call.

[0091] The message exchange control unit 12 of the telephone number investigation device 10 sends an INVITE request to the IP telephone terminal 50 to be investigated via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the IP telephone terminal 50's subscriber. (F1) At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request.

[0092] In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (F2), indicating that the request has been received in the SIP session, and also sends a code 183 Session Progress response (F3), indicating the progress of the call in the SIP session.

[0093] Next, the incoming fixed IMS network 30 sends a code 183 Session Progress response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (specifically, the message exchange control unit 12) (F4), indicating the progress of the call in the SIP session, and also sends a code 200 OK response (F5) indicating that the request (specifically, the INVITE request) has been successfully processed in the SIP session. At this point, communication is established between the telephone number lookup device 10 and the IP phone terminal 50.

[0094] In this case, the telephone number investigation and determination unit 13 of the telephone number investigation device 10 determines that a landline phone actually exists as the IP phone terminal 50 to be investigated on the receiving end and that it is not busy (i.e., the telephone number of the IP phone terminal 50 to be investigated actually exists).

[0095] Next, the message exchange control unit 12 of the telephone number lookup device 10 sends an ACK (Acknowledgment) response indicating acknowledgment in the SIP session to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F6), and also sends a BYE request indicating termination of the SIP session (F7).

[0096] The message exchange control unit 12 of the telephone number investigation device 10, upon receiving a code 200 OK response (without receiving a code 180 Ringing response), sends a BYE request to disconnect communication with the receiving device under investigation (i.e., the IP phone terminal 50 under investigation). In other words, by sending a BYE request and promptly disconnecting communication upon receiving a code 200 OK response, the time spent communicating with the receiving IP phone terminal 50 under investigation can be shortened.

[0097] In response to a BYE request from the originating device (specifically, the telephone number lookup device 10), the receiving fixed IMS network 30 sends a code 200 OK response (F8) to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the originating fixed IMS network 20, indicating that the request (specifically, the BYE request) was successfully processed in the SIP session. This terminates the session between the telephone number lookup device 10 and the IP phone terminal 50, meaning that communication between the telephone number lookup device 10 and the IP phone terminal 50 is disconnected.

[0098] (Existence Determination / Part 3) Figure 9 illustrates Pattern 3 of the operation sequence when IPv4 is described as the network protocol in the SDP parameters and the above IPv4 SDP is described as the determination SDP parameters, and the IP phone terminal 50 under investigation is a real landline phone that is not currently in use.

[0099] The message exchange control unit 12 of the telephone number investigation device 10 sends an INVITE request to the IP telephone terminal 50 to be investigated via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the IP telephone terminal 50's subscriber. (F1) At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request.

[0100] In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (specifically, the message exchange control unit 12) indicating that the request has been received in the SIP session (F2), and also sends a code 200 OK response (F3) indicating that the request (specifically, the INVITE request) has been successfully processed in the SIP session. At this time, communication is established between the telephone number lookup device 10 and the IP phone terminal 50.

[0101] In this case, the telephone number investigation and determination unit 13 of the telephone number investigation device 10 determines that a landline phone actually exists as the IP phone terminal 50 to be investigated on the receiving end and that it is not busy (i.e., the telephone number of the IP phone terminal 50 to be investigated actually exists).

[0102] Next, the message exchange control unit 12 of the telephone number lookup device 10 sends an ACK (Acknowledgment) response indicating acknowledgment in the SIP session to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F4), and also sends a BYE request indicating termination of the SIP session (F5).

[0103] The message exchange control unit 12 of the telephone number investigation device 10, upon receiving a code 200 OK response (without receiving a code 180 Ringing response), sends a BYE request to disconnect communication with the receiving device under investigation (i.e., the IP phone terminal 50 under investigation). In other words, by sending a BYE request and promptly disconnecting communication upon receiving a code 200 OK response, the time spent communicating with the receiving IP phone terminal 50 under investigation can be shortened.

[0104] In response to a BYE request from the originating device (specifically, the telephone number lookup device 10), the receiving fixed IMS network 30 sends a code 200 OK response (F6) to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the originating fixed IMS network 20, indicating that the request (specifically, the BYE request) was successfully processed in the SIP session. This terminates the session between the telephone number lookup device 10 and the IP phone terminal 50, meaning that communication between the telephone number lookup device 10 and the IP phone terminal 50 is disconnected.

[0105] (In the case of determining existence / in conversation) Figure 10 illustrates the operation sequence when IPv4 is specified as the network protocol in the SDP parameters and the above IPv4 SDP is specified as the determination SDP parameters, and when a fixed-line telephone exists as the IP telephone terminal 50 to be investigated and is busy.

[0106] The message exchange control unit 12 of the telephone number investigation device 10 sends an INVITE request to the IP telephone terminal 50 to be investigated via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the IP telephone terminal 50's subscriber. (F1) At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request.

[0107] In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (F2), indicating that the request has been received in the SIP session, and also sends a code 486 Busy Here response (F3), indicating that the media resource requested by the caller in the SIP session is currently busy and the session cannot be started.

[0108] In this case, the telephone number investigation and determination unit 13 of the telephone number investigation device 10 determines that a landline phone actually exists as the IP phone terminal 50 to be investigated on the receiving end and that it is busy (i.e., the telephone number of the IP phone terminal 50 to be investigated actually exists).

[0109] Next, the message exchange control unit 12 of the telephone number lookup device 10 sends an ACK (Acknowledgment) response, indicating acknowledgment in the SIP session, to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F4). This terminates the session related to the INVITE request from the telephone number lookup device 10.

[0110] (Existence, existence or missing number determination) Figures 7 to 10 above illustrate the operation sequence when the telephone number of the IP phone terminal 50 is determined to be real. In addition, in the prior art, as shown in Figure 4, an INVITE request is sent to the receiving fixed IMS network 30 with SDP parameters attached to the INVITE request to the IP phone terminal 50 under investigation. If the response message returned from the receiving fixed IMS network 30 is code 404 Not Found, it is determined to be a missing number. However, after investigating many telephone numbers, it was found that there are cases where the telephone number is real even if the response message is code 404 Not Found, and that there is a discrepancy between the actual status and the status determined based on the response message. The inventors of this invention have diligently investigated the cause of this problem and have found that there are multiple patterns, as shown below, where the source of the code 404 Not Found (404 error) is different. For example, as shown in Figure 11, if the telephone number is not registered on the SIP server, there is no specific user associated with the telephone number under investigation, the source of the 404 error is the receiving fixed IMS network, and the telephone number under investigation is missing. Furthermore, even if the telephone number under investigation does exist, if it is a sub-number of a representative, as shown in Figure 12, the incoming call will be rejected by the private network (PBX) connected to the receiving fixed IMS network 30, and the response from the private network (PBX) will be the source of the 404 error. In addition, as shown in Figure 13, if the IP phone terminal 50 exists but is set to be an outgoing-only user (HGW / OGW), the response from the IP phone terminal 50 will be the source of the 404 error.

[0111] If the determination of whether a number is real or missing is made solely based on the 404 Not Found code, many real phone numbers will be included in the list of missing numbers, compromising the reliability of the phone number investigation. To address this, one possible approach is to analyze the voice guidance after receiving the 404 Not Found response when the answering message is 404 Not Found, create text data from the audio file based on the voice guidance, and then use this text data to finally determine whether the IP phone terminal under investigation is real or missing. However, performing the above voice guidance analysis for every phone number that receives a 404 Not Found response would be extremely time-consuming and inefficient.

[0112] Therefore, the inventors of the present invention conducted a detailed study on the case where an INVITE request is sent to the IP phone terminal 50 under investigation with SDP parameters attached, and the response message returned from the IMS network 30 is code 404 Not Found. As a result, they found that when an INVITE request is sent to the IMS network 30 and the response message returned from the IMS network 30 is code 404 Not Found, the elapsed time until receiving the code 404 Not Found response tends to differ depending on whether the telephone number is real or missing, that is, depending on the difference in the source of the 404 error described above. More specifically, if the telephone number under investigation is real, the telephone number is real if the elapsed time T1 from the timing T0 when the INVITE request is sent until receiving the code 404 Not Found exceeds a predetermined time (e.g., 0.7 seconds). Furthermore, it was found that if the elapsed time T1 does not exceed the predetermined time, there is a mix of existing and missing numbers, and it is difficult to determine whether a number is existing or missing based solely on the reception time T1 mentioned above.

[0113] Based on the facts described above, in this embodiment, if the received response message is code 404 Not Found, and the elapsed time T1 until the receipt of the code 404 Not Found response exceeds a predetermined reference time (e.g., 0.7 seconds), it is determined that the telephone number of the IP phone terminal associated with the telephone number under investigation actually exists. If the elapsed time T1 does not exceed the predetermined reference time, it is determined that the telephone number of the IP phone terminal under investigation is either missing or actually exists.

[0114] Figure 14 shows a flowchart that includes a determination procedure to be performed when, based on the facts described above, an INVITE request is sent to the receiving fixed IMS network 30 with SDP parameters attached to the INVITE request for the IP phone terminal 50 under investigation, and the response message returned from the receiving fixed IMS network 30 is code 404 Not Found (404 error received). Figure 15 is a diagram that explains the operation sequence for determining whether the IP phone terminal 50 under investigation (in other words, the telephone number) is real or missing, when IPv4 is described as the network protocol as the SDP parameter and the above IPv4 SDP is described as the determination SDP parameter.

[0115] The following describes, with reference to Figures 14 and 15, the telephone number lookup device 10, the telephone number lookup method, program, and information provision device for when the response message configured according to the present invention is code 404 Not Found.

[0116] (Sending an invitation) In this embodiment, the outgoing device, the telephone number lookup device 10, has a list of telephone numbers to be looked up. The message exchange control unit 12 of the telephone number lookup device 10 sends an INVITE request (F1) to the IP telephone terminals 50a, 50b, 50c, etc. to be looked up via the outgoing fixed IMS network 20 and the incoming fixed IMS network 30, such as the fixed telephone network of the service provider of the IP telephone terminals 50 to be looked up, via the outgoing fixed IMS network 20. At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request. The timing at which such an INVITE request is sent is the reference time T0, which is the basis for the elapsed time T1 described later.

[0117] (404 error received) In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (F2), indicating that the request has been received in the SIP session, and also sends a code 404 Not Found response (F3), indicating that the media resource requested by the caller in the SIP session could not be found. When such a code indicating 404 Not Found (404 error) is received, the elapsed time T1 since the receipt of the 404 error (step S2) is stored in an appropriate memory in the telephone number lookup device 10. As described above, an INVITE request to the IP phone terminal 50 under investigation is sent to the receiving fixed IMS network 30 with SDP parameters attached (step S1). If the response message returned from the receiving fixed IMS network 30 is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, it is determined that the telephone number of the IP phone terminal 50 under investigation actually exists (the flowchart in Figure 14 omits the details of this determination procedure).

[0118] (404 reception time determination) Next, the process proceeds to step S3, where it is determined whether the 404 error reception time, i.e., the elapsed time T1, is less than a predetermined reference time (e.g., 0.7 seconds). If the elapsed time T1 is equal to or greater than the reference time, the result is "No" and the process proceeds to step S4. If the elapsed time T1 is less than the reference time, the result is "Yes" and the process proceeds to step S5.

[0119] (Determination of existence) Based on prior verification, if the elapsed time T1 is equal to or greater than the reference time, it can be determined that the phone number is real. Therefore, in step S4, the phone number is determined to be "real," and the data related to the usage history of the phone number under investigation in the phone number history database 15 is updated.

[0120] (Missing number or existence determination) Furthermore, if the elapsed time T1 is less than the reference time, there is a possibility that the number is either real or missing. Therefore, in step S5, it is determined that the telephone number of the IP phone terminal under investigation is either missing or real.

[0121] According to the embodiment described above, when a 404 Not Found response indicating that the media resource requested by the caller cannot be found is received in a SIP session, it becomes possible to distinguish between telephone numbers that can be determined to exist and telephone numbers that are either missing or existing, based on the elapsed time T1 since the receipt of the 404 error (step S2). Therefore, by storing such information in an appropriate storage device in the telephone number lookup device 10, it becomes possible to exclude telephone numbers that have been determined to exist from the telephone number list used in the subsequent usage status determination, thereby eliminating the need for unnecessary investigations.

[0122] (Creating a list of phone numbers) As described above, after receiving a 404 error, it is determined whether the number is real, missing, or real. In step S6, a list of telephone numbers is created by excluding the telephone numbers of IP phone terminals that were determined to be real from the list of telephone numbers to be investigated, based on the telephone numbers to be investigated that were determined to be either missing or real. This list of telephone numbers is a list of telephone numbers from which a 404 error was received, excluding the numbers that were determined to be real in step S4 described above.

[0123] (Assessment of usage status) As shown in Figure 6, the telephone number lookup device 10 of this embodiment includes a voice conversion unit 16. After the 404 error described above is received, if any voice guidance is transmitted, the voice conversion unit 16 records (in other words, packet captures) the voice guidance and stores it as voice data. The voice conversion unit 16 also includes a voice recognition unit (not shown) that converts the stored voice data into text (i.e., speech to text) and stores the converted text data in memory or a storage device (neither of which is shown). The text data can then be analyzed by the telephone number lookup determination unit 13.

[0124] In step S7, based on the telephone number list, the message exchange control unit 12 and the telephone number investigation and determination unit 13 are executed to extract an audio file from the voice guidance after receiving the code 404 Not Found response, create text data based on the audio file, and determine based on the text data whether the IP telephone terminal under investigation is missing or actually exists.

[0125] The determination of usage status in step S7 of this embodiment will be explained in more detail. Once the above-described telephone number list has been created, the voice guidance call control server (not shown) installed in the voice conversion unit 16 of the telephone number search device 10 retrieves the telephone numbers to be searched that are registered in the telephone number list. Next, following the above-described operation sequence, an INVITE request is sent to the IP telephone terminal 50 to be searched. Then, a code 100 Trying response indicating that the request has been received in the SIP session is returned from the incoming fixed IMS network 30 via the outgoing fixed IMS network 20 to the telephone number search device 10 (specifically, the message exchange control unit 12), and a code 404 Not Found response indicating that the media resource requested by the caller could not be found in the SIP session is also returned.

[0126] After receiving the aforementioned Code 404 Not Found response, voice guidance is broadcast from the receiving fixed IMS network 30. The voice conversion unit 16 is equipped with a voice guidance call control server that, as described above, records (in other words, packets captures) the voice guidance and stores it as voice data, and saves the recorded and stored voice data to memory or a storage device. It also includes a voice recognition unit (not shown) that converts the voice data stored in the voice guidance call control server to text (i.e., speech to text) and saves the converted text data to memory or a storage device (neither of which is shown).

[0127] Then, the text data is analyzed by the telephone number investigation and determination unit 13 to determine whether the IP telephone terminal 50 under investigation is missing or actually exists.

[0128] The analysis of the text data described above is determined, for example, based on the name of the contract carrier, the name of the contracting company, and typical words contained in the response message. For example, the determination is made as follows:

[0129] The voice guidance message when the phone number being investigated is missing is, for example, as follows: "The phone number you have dialed is currently not in service. Please check the number and try again." By analyzing this type of text data, it is possible to determine if the phone number being investigated is missing or unavailable.

[0130] Furthermore, even if a 404 Not Found response is received for the phone number under investigation, if the phone number is real, a busy tone will be transmitted afterward. In this case, the voice conversion unit 16 does not recognize the busy tone as speech, and no text is generated based on the packet-captured speech data. Therefore, it is possible to determine that the phone number under investigation "exists" based on the fact that no text is generated.

[0131] As a result, step S7 for determining the usage status is completed, and it is determined whether the telephone number under investigation is either "existent" or "missing," and the data related to the usage history of the telephone number under investigation in the telephone number history database 15 is updated.

[0132] According to the embodiment described above, even if a telephone number receives a code 404 Not Found response, if the elapsed time T1 exceeds the reference time, it is determined to exist in step S4. Then, the usage status is determined based on the list of excluded telephone numbers, and it is efficiently determined whether the telephone number under investigation that received a code 404 Not Found response is missing or exists.

[0133] The telephone number investigation device 10 stores a program for executing the flowchart described with reference to Figure 14, and the telephone number investigation method described above is performed by executing the program.

[0134] Figure 16 illustrates the operation sequence when, as an SDP parameter, IPv4 is specified for the network protocol (in other words, the Internet Protocol, IP version) among the SDP parameters for determination, and only G.711 μ-law is specified for the voice codec among the IPv4 SDP (i.e., G.722 is not included), and the IP telephone terminal 50 under investigation (in other words, the telephone number) is missing. The basic sequence on which this operation sequence is based is specified in the TTC standard TR-1088.

[0135] In this case, in response to the INVITE request (F1) from the telephone number lookup device 10 (specifically, the message exchange control unit 12), the incoming fixed IMS network 30 sends back a code 100 Trying response (F2) to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20, indicating that the request has been received in the SIP session, and also sends back a code 183 Session Progress response (F3) indicating the progress of the call in the SIP session.

[0136] Next, the telephone number lookup device 10 (specifically, the message exchange control unit 12) sends a PRACK (Provisional Response Acknowledgement) request, which is a provisional response confirmation in the SIP session, to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F4). In response, the receiving fixed IMS network 30 sends back a code 200 OK response to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the originating fixed IMS network 20, indicating that the request (specifically, the PRACK request) in the SIP session was processed successfully (F5).

[0137] This response is the same as pattern 2 of the operation sequence when a landline phone actually exists as the IP phone terminal 50 being investigated on the receiving end and is not busy, in that it receives a code 200 OK response without receiving a code 180 Ringing response (see Figure 8).

[0138] Therefore, even though the IP phone terminal 50 being investigated (in other words, the phone number) is actually missing, the phone number investigation and determination unit 13 of the phone number investigation device 10 mistakenly determines that a landline phone actually exists as the IP phone terminal 50 being investigated on the receiving end (and the message exchange control unit 12 sends a BYE request).

[0139] Therefore, when offering IPv4 as the network protocol among the SDP parameters used for determination, G.722 should be specified in addition to G.711 μ-law for the audio codec among the other SDP parameters used for determination (i.e., G.711 μ-law and G.722 should be offered simultaneously).

[0140] As a result, as shown in Figure 12, in response to an INVITE request (F1) from the telephone number lookup device 10 (specifically, the message exchange control unit 12), the incoming fixed IMS network 30 sends a code 100 Trying response (F2) to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20, indicating that the request has been received in the SIP session, and also sends a code 404 Not Found response (F3) indicating that the media resource requested by the caller in the SIP session could not be found. This makes it possible to correctly determine that the incoming IP phone terminal 50 (in other words, the telephone number) to be looked up is missing using the flowchart shown in Figure 14 above.

[0141] (Transfer determination) Figure 17 illustrates the operation sequence when IPv4 is specified as the network protocol in the SDP parameters, and the above IPv4 SDP is specified for the determination SDP parameters, and the IP phone terminal 50 under investigation is relocated.

[0142] The message exchange control unit 12 of the telephone number investigation device 10 sends an INVITE request to the IP telephone terminal 50 to be investigated via the originating fixed IMS network 20 and the receiving fixed IMS network 30, such as the fixed telephone network of the IP telephone terminal 50's subscriber. (F1) At this time, the above IPv4 SDP is described as the determination SDP parameter (note that the network protocol is IPv4) included in the INVITE request.

[0143] In response, the incoming fixed IMS network 30 sends a code 100 Trying response (specifically, the message exchange control unit 12) via the outgoing fixed IMS network 20 to the telephone number lookup device 10 (F2), indicating that the request has been received in the SIP session, and also sends a code 183 Session Progress response (F3), indicating the progress of the call in the SIP session.

[0144] Furthermore, a relocation guidance message informing the recipient that the telephone number of the receiving device has changed, along with the new telephone number (in other words, a relocation guidance message informing the recipient that the receiving device has moved, along with the new telephone number), is transmitted from the receiving fixed IMS network 30 to the telephone number lookup device 10 (specifically, the message exchange control unit 12) via the sending fixed IMS network 20, as a Real-time Transport Protocol (RTP) message. The duration of the relocation guidance message is, for example, about 60 to 80 seconds.

[0145] After the transfer guidance is completed, a code 410 Gone response is sent from the incoming fixed IMS network 30 to the outgoing fixed IMS network 20 and then to the telephone number lookup device 10 (specifically, the message exchange control unit 12), indicating that the media resource requested by the caller in the SIP session previously existed but no longer does (F4).

[0146] In this case, the telephone number investigation and determination unit 13 of the telephone number investigation device 10 determines that the IP phone terminal 50 being investigated on the receiving end has moved (i.e., the telephone number of the IP phone terminal 50 being investigated is missing).

[0147] The telephone number investigation device 10 may, when a guidance message is received, record (in other words, packet capture) the guidance message using the voice conversion unit 16 described above and store it as voice data. If a code 410 Gone response is returned following the guidance message, the device may also save the recorded and stored voice data as voice data including the destination telephone number of the IP phone terminal 50 being investigated on the receiving end to memory or a storage device (neither of which are shown).

[0148] The telephone number investigation device 10 may further convert the voice data stored as voice data including the new telephone number of the IP phone terminal 50 being investigated on the receiving end into text, and save the converted text data as text data including the new telephone number of the IP phone terminal 50 being investigated on the receiving end into memory or a storage device (neither of which are shown in the figures).

[0149] In other words, the telephone number investigation device 10 may use relocation guidance, specifically using the voice conversion unit 16, to convert the voice data transmitted as relocation guidance into text data, thereby obtaining the telephone number information of the new address of the IP phone terminal 50 being investigated on the receiving end.

[0150] Next, the message exchange control unit 12 of the telephone number lookup device 10 sends an ACK (Acknowledgment) response, indicating acknowledgment in the SIP session, to the receiving fixed IMS network 30 via the originating fixed IMS network 20 (F5). This terminates the session related to the INVITE request from the telephone number lookup device 10.

[0151] Figure 18 shows a summary of the method for investigating the usage status (specifically, existence (available, busy), missing, and transfer) of the telephone number of the IP phone terminal 50 (specifically, for example, a 0ABJ type landline telephone number) based on the operation sequence described above.

[0152] Regarding the usage status of fixed-line telephone numbers of type 0ABJ for IP phone terminals 50 connected to telecommunications carriers, by specifying IPv4 for the network protocol (in other words, Internet Protocol, IP version) among the SDP parameters, and by making an SDP offer (i.e., an INVITE request) using IPv4 SDP for other SDP parameters, it is possible to accurately determine whether the number is active (free, busy), active or unavailable, or transferred. Furthermore, by implementing the telephone number investigation method based on the flowchart explained using Figure 14 above, it becomes possible to determine whether a telephone number that has been determined to be active or unavailable is actually active or unavailable.

[0153] As an example of a specific configuration of the telephone number investigation program according to the present invention, the telephone number investigation program according to an embodiment is as shown in the flowchart explained with reference to Figure 14, and is a program implemented in a telephone number investigation device 10 (see Figures 1 and 6) that is connected to a plurality of IP telephone terminals 50 connected to a receiving fixed IMS network 30 via a sending fixed IMS network 20.

[0154] The telephone number investigation program according to this embodiment causes a computer (specifically, a telephone number investigation device 10) connected to a plurality of IP telephone terminals 50 connected to a receiving fixed IMS network 30 via a sending fixed IMS network 20 to send an INVITE request to the receiving fixed IMS network 30 with SDP parameters attached to the INVITE request to the IP telephone terminal 50 to be investigated; to receive a response message from the receiving fixed IMS network 30; and to determine the telephone number usage status of the IP telephone terminal 50 to be investigated according to the response message.

[0155] Furthermore, the telephone number search program according to the embodiment is configured such that the SDP parameters are set to IPv4 for the network protocol, audio only for the media type, RTP / AVP only for the media transport protocol, and G.711 μ-law and G.722 for the audio codecs (i.e., SDP for IPv4).

[0156] (Telephone number information provision system) Figure 19 is a system configuration diagram of a telephone number information provision system 100 according to an embodiment, which is an example of a specific configuration of the telephone number information provision system according to the present invention.

[0157] The telephone number information provision system 100 according to this embodiment includes one or more user terminals 90 and a telephone number lookup server (specifically, a telephone number lookup device 10) which is connected to the user terminals 90 via an IP network 80 and also to a network not shown (for example, a caller fixed IMS network 20).

[0158] The telephone number information provision system 100 according to this embodiment includes a telephone number research server (specifically, a telephone number research device 10) and a user terminal 90. When the telephone number research server (specifically, the telephone number research device 10) receives a request for telephone number research information provision for an IP telephone terminal 50 from the user terminal 90, it includes a network interface unit 11 that transmits the telephone number usage status of the IP telephone terminal 50, as determined by the telephone number research determination unit 13, to the user terminal 90 that made the request via the IP network 80 (see Figure 6).

[0159] When the telephone number research server (specifically, the telephone number research device 10) receives a request for telephone number research information regarding the telephone number to be researched from a user terminal 90 via the IP network 80, it refers to a recording medium (specifically, the telephone number history database 15) which stores telephone number history information recorded chronologically with a timestamp indicating the date and time of determination attached to each determination result of the telephone number usage status, and transmits the telephone number history information to the user terminal 90 that made the request for telephone number research information via the IP network 80.

[0160] The recording medium containing telephone number history information (specifically, the telephone number history database 15) may be distributed independently to users who require it. The recording medium containing telephone number history information (telephone number history database 15) is, for example, a recording medium that records whether or not the telephone number being investigated actually exists, generated by a telephone number investigation device 10 connected to the telecommunications carrier network via a dedicated line, and may be used for searching in the recipient's system.

[0161] The recording medium storing telephone number history information (specifically, the telephone number history database 15) is a collection of results determining the validity of the telephone number usage status of the receiving telephone terminal (specifically, a landline telephone as an IP telephone terminal 50). For example, each determination result is assigned a timestamp indicating the date and time of determination, and is recorded in chronological order.

[0162] The distribution of recording media containing telephone number history information (specifically, the telephone number history database 15) is not limited to distribution in the form of a database recorded on a DVD or hard disk, but also includes distribution using communication lines.

[0163] According to the telephone number investigation device 10 of this embodiment, it is possible to accurately determine whether the telephone number of the IP phone terminal 50 is in use (valid (existing)) or not in use (invalid (missing number)).

[0164] According to the telephone number survey program of the embodiment, the telephone number survey device 10 sequentially reads and executes the program recorded in memory (not shown), thereby enabling accurate surveying of telephone number usage in the receiving fixed IMS network 30 by utilizing an IMS interconnection interface or the like for inter-carrier interconnection.

[0165] According to the telephone number information provision system 100 of this embodiment, it is possible to provide users who need the information on whether a telephone number is in use (valid (existing)) or not in use (invalid (missing number)), as determined by the telephone number investigation device 10. Furthermore, by distributing the recording medium containing the telephone number history information (specifically, the telephone number history database 15) to users who need the information, it becomes possible to utilize it on the user side, and to provide useful information, for example, in credit assessment.

[0166] Although embodiments of the present invention have been described above, the specific configurations of the present invention are not limited to the embodiments described above. The present invention also includes forms in which modifications and changes are made to the above embodiments without departing from the spirit of the invention. [Explanation of symbols]

[0167] 10: Telephone number lookup device 11: Network Interface Section 12: Message Exchange Control Unit 13: Telephone Number Investigation and Judgment Department 14: Telephone number history generation unit 15: Telephone Number History Database 16: Voice Conversion Unit 20: Originating fixed IMS network 20a: SIP server 21: Sender IBCF 30: Destination fixed IMS network 30a: SIP server 30b: SIP server 30c: SIP Server 31: Incoming IBCF 50, 50a, 50b, 50c: IP phone terminals 90: User terminal 100: Information Provision System

Claims

1. A telephone number lookup device connected to a plurality of IP telephone terminals connected to a receiving fixed IMS network including a SIP server via a sending fixed IMS network including a SIP server, A message exchange control unit that adds SDP parameters to the INVITE request to the IP phone terminal under investigation, transmits the INVITE request to the receiving fixed IMS network, and receives a response message from the receiving fixed IMS network, The system includes a telephone number investigation and determination unit that determines the usage status of the telephone number of the IP phone terminal under investigation in response to the aforementioned response message, The SDP parameters are described as follows: the network protocol is IPv4, the media type is audio only, the media transport protocol is RTP / AVP only, and the audio codecs include G.711μ-law and G.

722. The aforementioned telephone number investigation and determination unit, If the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, it is determined that the telephone number of the IP phone terminal being investigated actually exists. If the response message is code 404 Not Found, the telephone number investigation device determines that the telephone number of the IP telephone terminal associated with the telephone number under investigation exists if the elapsed time from sending the INVITE request to receiving the response message of code 404 Not Found exceeds a predetermined reference time for determining whether the elapsed time is long because the incoming call was rejected by a private network connected to the receiving fixed IMS network and the response from the private network is the source of the code 404 Not Found error, or because the IP telephone terminal exists but is set to outgoing-only and the response from the IP telephone terminal is the source of the code 404 Not Found error.

2. In addition to the above configuration, it is equipped with a voice conversion unit, For the IP phone terminals associated with the aforementioned telephone numbers under investigation that are determined to be either missing or existing, a list of telephone numbers is created by excluding the telephone numbers of the IP phone terminals that are determined to be existing from the list of telephone numbers under investigation. A telephone number investigation device according to claim 1, wherein, based on the telephone number list, the message exchange control unit and the telephone number investigation and determination unit are executed to determine the usage status of the telephone number of the IP telephone terminal to be investigated, an audio file is extracted from the voice guidance after receiving the code 404 Not Found response, text data is created based on the audio file, and based on the text data, it is determined that the IP telephone terminal to be investigated is either missing or in existence.

3. A method for investigating telephone numbers, which involves investigating the usage status of telephone numbers of IP telephone terminals to be investigated, using a device connected via a dispatching fixed IMS network including a SIP server to a plurality of IP telephone terminals connected to a receiving fixed IMS network including a SIP server, A transmission step of adding SDP parameters to the INVITE request to the IP phone terminal under investigation and sending the INVITE request to the receiving fixed IMS network, A receiving step of receiving a response message from the aforementioned fixed IMS network, The process includes a determination step of determining the usage status of the telephone number of the IP phone terminal under investigation in response to the aforementioned response message, The SDP parameters are set as follows: network protocol is IPv4, media type is audio only, media transport protocol is RTP / AVP only, and audio codecs are G.711 μ-law and G.

722. In the determination step, if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here, it is determined that the telephone number of the IP phone terminal being investigated actually exists. A method for investigating a telephone number, characterized in that, if the response message is code 404 Not Found, the elapsed time from sending the INVITE request to receiving the response message of code 404 Not Found exceeds a predetermined reference time for determining whether the elapsed time is long because the incoming call was rejected by a private network connected to the receiving fixed IMS network and the response from the private network is the source of the code 404 Not Found error, or whether the IP phone terminal exists but is set to outgoing-only and the response from the IP phone terminal is the source of the code 404 Not Found error, then it is determined that the telephone number of the IP phone terminal associated with the telephone number under investigation exists; if the elapsed time does not exceed the predetermined reference time, then it is determined that the telephone number of the IP phone terminal under investigation is either missing or exists. A device for looking up call numbers is provided.

4. The method for investigating the aforementioned telephone number includes, in addition to the above configuration, a voice conversion step. The aforementioned determination step creates a list of telephone numbers by excluding the telephone numbers of the IP phone terminals determined to be the telephone numbers of the IP phone terminals associated with the telephone numbers under investigation, based on the telephone numbers under investigation that are determined to be either missing or existing. A method for investigating a telephone number according to claim 3, comprising: performing the transmission step, the reception step, and the determination step based on the telephone number list to determine the usage status of the telephone number of the IP telephone terminal to be investigated; performing a voice conversion step from the voice guidance after receiving the code 404 Not Found response to extract a voice file and create text data based on the voice file; and determining, based on the text data, whether the IP telephone terminal to be investigated is missing or in existence.

5. A computer connected via a sending-side fixed IMS network including a SIP server to a plurality of IP telephone terminals connected to a receiving-side fixed IMS network including a SIP server, A transmission process that adds SDP parameters to the INVITE request to the IP phone terminal under investigation and causes the INVITE request to be sent to the receiving fixed IMS network, A receiving process that receives a response message from the aforementioned fixed IMS network, The system performs at least a determination process that determines the usage status of the telephone number of the IP phone terminal under investigation in response to the aforementioned response message, The SDP parameters are set as follows: Network protocol is IPv4, media type is audio only, media transport protocol is RTP / AVP only, and audio codecs are G.711 μ-law and G.

722. The determination process determines that the telephone number of the IP phone terminal under investigation exists if the response message is code 180 Ringing, code 183 Session Progress, code 200 OK, or code 486 Busy Here. A telephone number investigation program characterized in that, if the response message is code 404 Not Found, the elapsed time from sending the INVITE request to receiving the response message code 404 Not Found exceeds a predetermined reference time for determining whether the elapsed time is long because the incoming call was rejected by a private network connected to the receiving fixed IMS network and the response from the private network is the source of the code 404 Not Found error, or whether the IP phone terminal exists but is set to outgoing-only and the response from the IP phone terminal is the source of the code 404 Not Found error, then it is determined that the telephone number of the IP phone terminal associated with the telephone number under investigation exists. If the elapsed time does not exceed the predetermined reference time, the program performs a process to determine whether the telephone number of the IP phone terminal under investigation is missing or exists.

6. The aforementioned survey program includes, in addition to the above configuration, a speech conversion processing unit. The aforementioned determination process is: For each of the IP phone terminals associated with the aforementioned telephone numbers under investigation that are determined to be either missing or existing, a list of telephone numbers is created by excluding the telephone numbers of terminals determined to be IP phone terminals from the investigation. A telephone number investigation program according to claim 5, comprising: executing the transmission process and reception process and the determination process based on the telephone number list to determine the usage status of the telephone number of the IP telephone terminal to be investigated; extracting an audio file from the voice guidance after receiving the code 404 Not Found response using the voice conversion processing unit, creating text data based on the audio file, and determining based on the text data whether the IP telephone terminal to be investigated is missing or in existence.

7. A telephone number lookup device according to claim 1, Having a user terminal, The telephone number investigation device, upon receiving a request for telephone number investigation information regarding the IP telephone terminal from the user terminal, includes a network interface unit that transmits the telephone number usage status of the IP telephone terminal, as determined by the telephone number investigation determination unit, to the user terminal that made the request via the IP network. A telephone number information provision system characterized by the following features.

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