JP2009044419A - Sip server, its control method, and ip telephone system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish a connection between a telephone terminal as a calling side and a telephone terminal as an expected arrival side more rapidly and securely when a connection based upon a calling request from the telephone terminal as the calling side is not established in an IP (Internet Protocol) telephone system. <P>SOLUTION: In the IP telephone system, if establishment of a session for a calling request from one terminal (terminal A) ends in failure, the SIP (Session Initiation Protocol) server transmits an INVITE message to both the terminal as the expected arrival side and the terminal as the calling side ([19]Invite, [20]Invite) when the terminmal (B) as the expected arrival side enters a resist state at the calling request, so that a session is established between the terminals (terminal A and terminal B). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a SIP (Session Initiation Protocol) server, a control method thereof, and an IP telephone system, and more particularly, to a SIP server for establishing a session between terminals in response to a call request from a calling terminal, a control method thereof, and an IP telephone. About the system.

  With the recent spread of Internet devices, for example, IP telephone systems that provide telephone services using an IP (Internet Protocol) network are being used. In the IP telephone system, unlike a fixed telephone, a telephone terminal is not always connected to a line (registered in a server). This is because the connection status to the network changes depending on the power on / off state of the telephone terminal, the interruption of communication on the network path, and the like. In such an IP telephone system, various studies have been made regarding establishment of a call.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2001-86193), a terminal that is not connected to the Internet at the time of an incoming call is referred to as a second terminal in a call signal received at a first access point. A technique for connecting a receiving terminal and a second access point and registering a second access point and a first access point when registered in an access point is disclosed.

  Patent Document 2 (Japanese Patent Laid-Open No. 09-321914) notifies that an incoming call has been received by transmitting a voice mail to a telephone terminal on the receiving side when a call cannot be established in the IP telephone system. Technology is disclosed.

  Patent Document 3 (Japanese Patent Laid-Open No. 2005-322974) discloses a technique for storing information to that effect in a dedicated device (uncompleted call information notification device) when a call cannot be established in the IP telephone system. It is disclosed.

Further, in Patent Document 4 (2005-86544), reservation information related to connection is acquired, and when it is determined that the state of the destination communication terminal matches the connection condition based on the acquired reservation information, A technique for executing processing for establishing a connection between a communication terminal and a destination communication terminal is disclosed.
JP 2001-86193 A JP 09-321914 A JP 2005-322974 A JP 2005-86544 A

  As described above, conventionally, in the IP telephone system, a technique for establishing a call more reliably, and a terminal that is scheduled to become a receiving-side telephone terminal when a call cannot be established (hereinafter, appropriately, Various techniques have been disclosed for notifying a “scheduled incoming terminal” and “scheduled incoming telephone terminal”).

  In the IP telephone system, for example, a user of a calling telephone terminal wants to start a call with a receiving telephone terminal earlier and more reliably, for example, disclosed in the cited document 4. Thus, according to the state of the destination communication terminal, specifically, as described in paragraph 0033 of the cited reference 4, etc., when the destination communication terminal moves into the communication range, the connection between the communication terminals is established. It is thought that it is effective to execute the process for the above.

  However, it is difficult to say that a call can be started simply by moving the communication terminal into the communication area, and another study is required. It is because the user of the communication terminal is not always in a state where the communication can be performed simply by moving the communication terminal into the calling area.

  The present invention has been conceived in view of such a situation, and its purpose is faster in the IP telephone system when a connection based on a call request from a calling telephone terminal is not established. Provided is a SIP server, a control method thereof, and an IP telephone system including such a SIP server, which can establish a connection between a calling side telephone terminal and an incoming call side telephone terminal reliably and reliably. That is.

  An SIP server according to an aspect of the present invention includes a registration control unit that controls login of a telephone terminal to an IP network, and a session control unit that controls a communication session formed between at least two telephone terminals in the IP network. The registration control means includes registration information storage means for storing information for identifying each telephone terminal logged in to the IP network, and the session control means receives the second telephone from the first telephone terminal. When the information requesting a call to the terminal is received, and the information specifying the second telephone terminal is not stored in the registration information storage means, the first telephone terminal receives the first Call failure information storage means for storing information indicating that the session establishment based on the call request to the telephone terminal 2 has failed, Judgment as to whether or not information specifying the second telephone terminal that is the telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means And the determination means determine that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal Transmitting means for transmitting a signal for establishing a session between them, and the determining means stores information for specifying the second telephone terminal continuously in the registration information storage means for a predetermined time. The information specifying the second telephone terminal is stored in the registration information storage means, and the transmission means determines that the second power terminal When it is determined that the information specifying the terminal is stored in the registration information storage unit, the information in the information stored in the call failure information storage unit continues for a certain period of time after the determination is made. When it is determined that the information specifying the first telephone terminal which is the call side telephone terminal is not stored in the registration information storage means, or in the information stored in the call failure information storage means When the determination of whether or not the information specifying the first telephone terminal which is the telephone terminal on the side is stored in the registration information storage means is performed a predetermined number of times, and is not stored more than a predetermined number of times When it is determined that the call request is transmitted from the first telephone terminal to the second telephone terminal, the session control means stores the information in the call failure information storage means. The memorized information is deleted when the amount of information stored in the call failure information storage means exceeds a predetermined amount or when a specific time has elapsed since being stored in the call failure information storage means And deleting means for notifying the calling side telephone terminal of the information deleted from the call failure information storage means by the deleting means that the information is deleted.

  A SIP server according to another aspect of the present invention includes a registration control unit that controls login of a telephone terminal to an IP network and a session control that controls a communication session formed between at least two telephone terminals in the IP network. The registration control means includes registration information storage means for storing information for identifying each telephone terminal logged in to the IP network, and the session control means receives the second information from the first telephone terminal. When the information requesting the call to the telephone terminal is received and the information specifying the second telephone terminal is not stored in the registration information storage means, the first telephone terminal A call failure information storage means for storing information indicating that the session establishment based on the call request to the second telephone terminal has failed; Judgment as to whether or not information specifying the second telephone terminal that is the telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means And the determination means determine that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal And transmitting means for transmitting a signal for establishing a session between them.

  Further, in the SIP server of the present invention, the determination means determines the second telephone terminal when the information specifying the second telephone terminal is stored in the registration information storage means for a predetermined time. It is preferable to determine that the specified information is stored in the registration information storage unit.

  In the SIP server of the present invention, the transmission means determines that the transmission means determines that the information specifying the second telephone terminal is stored in the registration information storage means by the determination means. When it is determined that the information specifying the first telephone terminal that is the calling telephone terminal in the information stored in the call failure information storage means is not stored in the registration information storage means, It is preferable that information indicating that a call request is made from the first telephone terminal is transmitted to the telephone terminal.

  In the SIP server of the present invention, the transmission means continues for a certain period of time after the determination means determines that the information specifying the second telephone terminal is stored in the registration information storage means. Then, when it is determined that the information specifying the first telephone terminal is not stored in the registration information storage means, the second telephone terminal has received a call request from the first telephone terminal It is preferable to transmit information to that effect.

  In the SIP server of the present invention, the transmission means determines that the information specifying the second telephone terminal is stored in the registration information storage means by the determination means, and then the first information If the information identifying the telephone terminal is stored in the registration information storage means a predetermined number of times, and if it is determined that the information is not stored more than a predetermined number of times, the second telephone terminal It is preferable to transmit information indicating that a call request has been received from the first telephone terminal.

  Further, in the SIP server of the present invention, the session control means is configured such that the amount of information stored in the call failure information storage means is greater than or equal to a predetermined amount by the information stored in the call failure information storage means. It is preferable to further include an erasing unit for erasing the information and a notification unit for notifying the calling side telephone terminal of the information erased by the erasing unit from the call failure information storage unit that the information is erased. .

  In the SIP server of the present invention, the session control means erases the information stored in the call failure information storage means when a specific time has elapsed since the information was stored in the call failure information storage means. It is preferable that the information processing apparatus further includes an erasing unit that performs erasure, and a notification unit that notifies the calling telephone terminal of the information that is erased by the erasing unit from the call failure information storage unit that the information is erased.

  The SIP server control method according to the present invention includes registration control means for controlling login of a telephone terminal to an IP network, and session control means for controlling a communication session formed between at least two telephone terminals in the IP network. A method for controlling a SIP server comprising: storing information for identifying each telephone terminal logged into the IP network; and requesting a call from the first telephone terminal to the second telephone terminal. Receiving the information; and when receiving information requesting a call from the first telephone terminal to the second telephone terminal, the second telephone terminal that is the telephone terminal on the receiving side of the call request Determining whether or not the telephone terminal is logged in; and if the second telephone terminal which is the telephone terminal on the incoming side of the call request is not logged in A step of storing information indicating that the establishment of a session based on a call request from the first telephone terminal to the second telephone terminal has failed, and the establishment of the session has failed. Determining whether or not the second telephone terminal that is the incoming call side telephone terminal is logged in in the information indicating, and so that the second telephone terminal that is the incoming call side telephone terminal is logged in If it is determined that the first and second telephone terminals are determined, a signal for establishing a session between them is transmitted to the first telephone terminal and the second telephone terminal.

  An IP telephone system according to the present invention includes a first telephone terminal, a second telephone terminal, and an SIP server that can be connected to the first and second telephone terminals via an IP network. The SIP server includes registration control means for controlling login of a telephone terminal to the IP network, and session control means for controlling a communication session formed between at least two telephone terminals in the IP network. The registration control means includes registration information storage means for storing information for identifying each telephone terminal logged into the IP network, and the session control means is configured to transfer information from the first telephone terminal to the second telephone terminal. Information for specifying the second telephone terminal in the registration information storage means when information requesting a call is received Call failure information storage means for storing information indicating that the establishment of a session based on a call request from the first telephone terminal to the second telephone terminal has failed when not stored; Judgment means for judging whether or not information for specifying the second telephone terminal which is a telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means And when the determination means determines that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal, And a transmission means for transmitting a signal for establishing a session between them.

  According to the present invention, the SIP server schedules an incoming call when a connection based on a call request from the first telephone terminal to the second telephone terminal fails and a session cannot be established between the two telephone terminals. A signal for establishing a session between the two telephone terminals is transmitted to both telephone terminals on condition that the second telephone terminal, which is the side telephone terminal, has logged into the network. Note that the fact that the second telephone terminal has logged in is likely to be in a state where the user of the second telephone terminal can make a call, at least as compared with the case where the second telephone terminal simply moves into the calling area. It is considered high.

  Therefore, according to the present invention, in the IP telephone system, when the session between the two telephone terminals based on the request for the call from the first telephone terminal to the second telephone terminal cannot be established, it is faster. In addition, it is possible to reliably make a call between both telephone terminals.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 is a diagram schematically showing the configuration of an IP telephone system according to the present invention. In the IP telephone system, a plurality of telephone terminals 200 and the SIP server 100 are connected via a network 500. In the IP telephone system, VoIP (Voice over Internet Protocol) technology is used.

FIG. 2 is a diagram schematically showing the configuration of the SIP server 100.
Referring to FIG. 2, SIP server 100 includes a communication unit 110 for connecting to network 500. The SIP server 100 also includes a registration information management unit 120, a registration management information storage unit 130, a presence information management unit 140, a presence information storage unit 150, a call connection control unit 160, and a call failure information storage unit 170.

  The registration information management unit 120 manages information related to a telephone terminal in a state in which a call with another telephone terminal can be made via the network 500 in the IP telephone system. Specifically, in the IP telephone system, when each telephone terminal 200 is connected (logged in) to the network 500, the SIP server 100 assigns an IP address to the telephone terminal and registers information about the telephone terminal. Management is performed in the management information storage unit 130. FIG. 4 schematically shows the contents stored in the registration management information storage unit 130.

  Referring to FIG. 4, in registration management information storage unit 130, information (terminal ID 132) for identifying each of telephone terminals 200 logged in to network 500, and an IP address (IP Address 134) and the IP telephone number (IP telephone number 136) assigned to the telephone terminal are stored in association with each other for each telephone terminal.

  In this specification, a state in which the telephone terminal 200 is given an IP address by logging into the network 500 is referred to as a “registration state”. The fact that the telephone terminal 200 stores information in the registration management information storage unit 130 is referred to as “registering with the SIP server 100”.

  In the IP telephone system according to the present embodiment, when each telephone terminal is in the registration state, information for logging out from each telephone terminal is input, or the connection path from each telephone terminal to network 500 is blocked. Then, the registration state of the telephone terminal is released, and thereby the information regarding the telephone terminal is deleted from the registration management information storage unit 130.

  Returning to FIG. 2, the registration information management unit 120 appropriately updates the storage contents in the registration management information storage unit 130 by managing the connection state of each telephone terminal 200 in the IP telephone system.

  In the IP telephone system of the present embodiment, each telephone terminal 200 in the registration state can register the state of the user of each telephone terminal 200 with respect to the SIP server 100. Such information is stored in the presence information storage unit 150. FIG. 5 schematically shows the contents stored in the presence information storage unit 150.

  Referring to FIG. 5, in the presence information storage unit 150, information (terminal ID 152) for specifying each of the telephone terminals 200 logged in to the network 500 is stored, similarly to the terminal ID 132 of the registration management information storage unit 130. Has been. Further, in the presence information storage unit 150, as in the registration management information storage unit 130, the IP address (IP address 154) assigned to each telephone terminal 200 is associated with the terminal ID 152 of each telephone terminal 200. It is remembered. In addition, the presence information storage unit 150 stores information (presence information 156) for specifying the user state of each telephone terminal 200.

  The presence information 156 of each telephone terminal 200 in the presence information storage unit 150 is transmitted from each telephone terminal 200. In other words, in the IP telephone system according to the present embodiment, the user of each telephone terminal 200 transmits information specifying his / her state (for example, “at present”, “out of seat”, etc.) to SIP server 100. can do. Upon receiving such information, the presence information management unit 140 of the SIP server 100 stores the received information as presence information 156 associated with the corresponding terminal ID 152 in the presence information storage unit 150.

  Returning to FIG. 2, the call connection control unit 160 performs session management (starting / continuing / ending a session) when a call is made between two or more telephone terminals 200 on a system using the VoIP technology. . Note that the call connection control unit 160 is in a case where a call request is made from one telephone terminal 200 to another telephone terminal 200 and the call terminal 200 is not in a registration state because the call terminal 200 is not in a registration state. When a session based on the call request cannot be established, information indicating that is stored in the call failure information storage unit 170. FIG. 6 schematically shows the contents stored in the call failure information storage unit 170.

  Referring to FIG. 6, in call failure information storage section 170, caller side telephone terminal 200 transmits a call request to SIP server 100 for a call request that has failed to establish a session as described above. Time (calling failure time 172), information specifying the calling telephone terminal 200 (calling terminal ID 174), and information specifying the incoming call terminal 200 (receiving terminal ID 176) Are stored in association with each other.

FIG. 3 is a diagram schematically showing the configuration of the telephone terminal 200.
Referring to FIG. 3, telephone terminal 200 includes a control unit 210 that controls the operation of telephone terminal 200 as a whole. In addition, the telephone terminal 200 includes an operation unit 216 operated by a user to input information to the telephone terminal 200, a storage unit 217 that stores various data and programs, and the SIP server 100 or It includes a communication unit 218 for transmitting / receiving information to / from another telephone terminal 200, a speaker 215 that outputs voice, and a microphone 214 that inputs voice to the telephone terminal 200. Next, in the IP telephone system of the present embodiment, information transmitted / received when a telephone call between telephone terminals 200 is performed and modes of transmission / reception will be described.

  FIG. 7 shows a timing chart when a call is normally made in the IP telephone system. In the following description, a call between a telephone terminal 200 called “terminal A” and a telephone terminal 200 called “terminal B” will be described as an example of a telephone call between two or more telephone terminals 200.

  Referring to FIG. 7, when an operation for instructing terminal A to make a call for a call with terminal B as the incoming call destination terminal is performed (1) call operation), terminal A performs a SIP server (SIP A message requesting communication start (INVITE message) is transmitted to the server 500) (2) Invite. In response to this, the SIP server transmits an INVITE message to the terminal B that is the incoming call side terminal (3) Invite.

  When the terminal B that has received the INVITE message is operated to respond to an incoming call based on the received INVITE message, the terminal B transmits an OK message to the SIP server (4) OK. In response to this, the SIP server transmits an OK message to terminal A, which is the calling terminal (5] OK).

  The terminal A that has received the OK message transmits an ACK message to the SIP server in order to respond to this (6) ACK. In response to this, the SIP server transmits an ACK message to terminal B (7) ACK.

  Through the transmission and reception of the messages 1] to 7] above, a session is established between the terminal A and the terminal B, and a call can be started.

  Then, when an operation for ending the call is performed at the terminal A (8] end operation), a BYE message is transmitted from the terminal A to the terminal B (9] BYE).

In response to this, the terminal B transmits an OK message (10] OK).
Thereby, the session between the terminal A and the terminal B is completed.

  The transmission / reception of information described with reference to FIG. 7 is an example in which both terminal A and terminal B are in a registration state.

  Next, a case will be described in which terminal B, which is a terminal scheduled to receive a call, is not in a registration state when terminal A transmits a call request message to the SIP server. FIG. 8 is an example of a timing chart in such a case.

  Referring to FIG. 8, when an operation for instructing terminal A to make a call with terminal B as the incoming call destination terminal is performed (11) call operation), from terminal A to the SIP server, An INVITE message is transmitted (12) Invite. In this case, since the terminal B is not in the registration state, the SIP server stores information in the call failure information storage unit 170, assuming that the session establishment based on the call request from the terminal A has failed. Specifically, the time when the terminal A transmitted the INVITE message to the SIP server is stored as the call failure time 172, the information specifying the terminal A is stored as the calling terminal ID 174, and the called terminal ID 176 is stored. As such, information specifying the terminal B is stored.

  Then, the SIP server transmits a message indicating that the establishment of the session with the terminal B has failed to the terminal A (13) Call failure notification.

  In response to this, the terminal A transmits an ACK message to the SIP server (14) ACK.

  Then, the SIP server transmits a BYE message to terminal A (15) BYE). In response to this, the terminal A transmits an OK message to the SIP server (16) OK.

  Then, consider a case where terminal B is in a registration state. That is, terminal B logs in to the network (17) login, and in response, the SIP server assigns an IP address to terminal B and notifies the terminal B of the IP address (18) IP address notification ).

  When the terminal (telephone terminal 200) newly enters the registration state, the SIP server determines whether or not information specifying the terminal is stored in the receiving terminal ID 176 of the call failure information storage unit 170. If it is determined that it is stored, an INVITE message is transmitted to the terminal specified by the receiving terminal ID 176 and the terminal stored in association with the terminal as the calling terminal ID 174 (19). Invite, 20] Invite).

  The terminal A and the terminal B that have received the INVITE message each transmit an OK message to the SIP server (21] OK, 22] OK). Then, in response to receiving the OK message, the SIP server transmits an ACK message to each of terminal A and terminal B (23] ACK, 24] ACK). Thereby, a session is established between the terminal A and the terminal B, and a call can be started.

  When an operation for terminating the call is performed at one terminal (terminal A in FIG. 8 (25) termination operation), a BYE message is sent from the terminal (terminal A) to the terminal of the other party (terminal B). Is transmitted (26) BYE), and in response thereto, an OK message is returned (from terminal B to terminal A). As a result, the session ends and the call ends.

  As described above, in the IP telephone system described with reference to FIG. 8, when the establishment of a session for a call request from a certain terminal fails, An INVITE message is transmitted from the SIP server to both the terminal on the incoming call side and the terminal on the calling side, and a session is established between the terminals. Note that, when a session is established by such a function of the SIP server, the call connection control unit 160 preferably deletes information in the call failure information storage unit 170 that is the basis of the establishment of the session. .

  In addition, the SIP server sends an INVITE message to both the terminal A and the terminal B in response to the fact that the terminal B, which is the terminal on the incoming side when the session establishment fails, logs in and enters the registration state. (19) Invite, 20] Invite), the INVITE message to the terminal A and the terminal B may be transmitted after the registration state of the terminal B continues for a predetermined time (for example, 10 seconds) to become the registration state. Further, when the amount of information stored in the call failure information storage unit 170 becomes a predetermined amount (when information on failure to establish a predetermined number of sessions is stored), the call connection control unit 160 makes a call It is preferable to delete information from the oldest failure time 172.

  In addition, the call connection control unit 160 deletes information stored in the call failure information storage unit 170 that has passed a specific time (for example, 1 hour) from the call failure time 172 (for example, 1 hour). Erasing) is preferable.

  In the present embodiment described above, in the case described with reference to FIG. 8, the terminal B which is the terminal on the receiving side of the terminal A that has output the call request was not in the registration state at the time of the call request. In this case, the SIP server waits (monitors) until the terminal B enters the registration state. When terminal B logged in and entered the registration state, terminal A was also in the registration state. Next, a case where terminal A is no longer in the registration state when terminal B is in the registration state will be described. FIG. 9 shows a timing chart in such a case.

  Referring to FIG. 9, when terminal A performs an operation for instructing a call with terminal B as the incoming call destination terminal (31) call operation), an INVITE message is sent from terminal A to the SIP server. It is transmitted (32) Invite. At this time, if the terminal B is not in the registration state, the SIP server appropriately stores information in the call failure information storage unit 170 and transmits a message notifying the terminal A that the session establishment has failed. (33) Call failure notification).

  In this example, it is assumed here that the registration state of the terminal A is canceled by cutting off the connection path between the terminal A and the network (network 500) or turning off the power of the terminal A.

  In this state, the terminal B logs in to the network (34) login, and in response, the SIP server gives an IP address to the terminal B and notifies the terminal B of the IP address (35) IP address notification ). When the SIP server determines that information specifying the terminal B in the registration state is stored in the receiving terminal ID 176 of the call failure information storage unit 170, the SIP server An INVITE message is sent (36) Invite. Note that since the terminal A, which is the calling terminal ID 174 stored in association with the receiving terminal ID 176, is not in a registration state at this time, the SIP server transmits an INVITE message to the terminal A at this time. Can not do it.

  In response to receiving the INVITE message from the SIP server, the terminal B transmits an OK message to the SIP server (37) OK. In response to this, an ACK message is transmitted from the SIP server to the terminal B (38) ACK.

Thereby, a session is established between the SIP server and the terminal B.
Then, the SIP server has made a call request from the terminal A to the terminal B stored as the receiving terminal ID 176 in the call failure information storage unit 170, but the session establishment based on the call request has failed. (39) Notification of incoming information).

  In response to this, an ACK message is transmitted from the terminal B to the SIP server (40) ACK, and in response, a BYE message is transmitted from the SIP server to the terminal B (41] BYE). In response to reception of the message, the terminal B transmits an OK message to the SIP server (42) OK.

Thereby, the session between the SIP server and the terminal B ends.
In the present embodiment described above, as described with reference to FIG. 9, when a call request for requesting establishment of a session with a terminal on the incoming call side is made from the terminal on the calling side, If the session based on the call request cannot be established and the calling terminal is no longer in the registration state when the terminal on the incoming call side is in the registration state, the SIP server A message notifying that a call request has been made from the calling terminal is transmitted to the terminal on the incoming call side.

  Further, as described with reference to FIG. 8, when the session establishment based on the call request of the caller terminal fails, between the caller terminal A and the SIP server, The session is temporarily ended (15] BYK, 16] OK).

  In order to establish a session between the calling side terminal and the incoming side terminal more quickly and more reliably when the incoming side terminal enters the registration state, the SIP server Even if the establishment of a session based on a call request from the caller terminal fails, the session with the caller terminal is not terminated and the call waiting terminal waits for a registration state. A timing chart for such an example is shown in FIG.

  In the timing chart of FIG. 10, transmission / reception of a message for ending the session between the SIP server and the terminal A even when the session establishment based on the call request of the first caller terminal fails (FIG. 8). 15] BYE, 16] OK) are omitted.

  In the example shown in FIG. 10, in the SIP server, one terminal of the SIP server is occupied by the terminal A unnecessarily until the terminal B enters the registration state. Therefore, in such an example, when the terminal B does not enter the registration state after a predetermined time has elapsed since the INVITE message was first transmitted from the terminal A to the SIP server (12) Invite. As shown in FIG. 8, it is preferable that a signal for terminating the session between the terminal A and the SIP server is transmitted / received.

  In the present embodiment described above, in the IP telephone system, the SIP server waits for the terminal to newly enter a registration state. Then, it is determined whether information specifying the terminal is stored in the receiving terminal ID 176 of the call failure information storage unit 170. Then, if it is determined that it is stored, an INVITE message is transmitted to the terminal specified by the receiving terminal ID 176 and the terminal stored in association with the terminal as the calling terminal ID 174.

  Note that the INVITE message transmitted to the calling terminal at this time is considered as if the SIP server is transmitting a message on behalf of the incoming call terminal, and transmitted to the incoming call terminal. The INVITE message to be sent is considered as if the SIP server is sending a message on behalf of the calling terminal. This is because the purpose is to establish a session between the calling side terminal and the incoming side terminal.

  In this embodiment, the INVITE message (19] Invite, 20] Invite) transmitted by the SIP server in this way is transmitted to the terminal on the incoming call side at the start of a normal session, that is, It is preferable that the message be different from the INVITE message (3 in FIG. 7) when the INVITE message is transmitted to the incoming call destination terminal based on the reception of the INVITE message from the calling terminal.

  Specifically, the INVITE message transmitted on behalf of the proxy may include a code that identifies the proxy. The message transmitted to the callee terminal includes information identifying the caller terminal, and the message transmitted to the caller terminal further includes information identifying the callee terminal Is preferred.

  The INVITE message transmitted on behalf of the proxy preferably includes a code (information) for displaying on the incoming call destination terminal and the calling terminal that the SIP server is transmitting the message on behalf of the proxy.

  In the present embodiment described above, the registration information management unit 120 and the registration management information storage unit 130 constitute registration control means for controlling login of the telephone terminal to the IP network.

  Further, the call connection control unit 160 and the call failure information storage unit 170 constitute session control means for controlling a communication session formed between at least two telephone terminals in the IP network.

  The registration management information storage unit 130 constitutes registration information storage means for storing information for identifying each telephone terminal logged into the IP network.

  The call failure information storage unit 170 receives information requesting a call from the first telephone terminal to the second telephone terminal, and stores the second telephone terminal in the registration information storage means. Call failure information storage for storing information indicating that establishment of a session based on a call request from the first telephone terminal to the second telephone terminal has failed when information for identifying the call is not stored Means are configured.

  Further, the call connection control unit 160 stores in the registration information storage unit information specifying the second telephone terminal that is the incoming call side telephone terminal in the information stored in the call failure information storage unit. If the determination means for determining whether or not the information for specifying the second telephone terminal is stored in the registration information storage means by the determination means, the first telephone Transmission means is configured to transmit a signal for establishing a session between the terminal and the second telephone terminal.

  In this embodiment, an INVITE message is exemplified as a signal for establishing a session.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows typically the structure of the IP telephone system which is one embodiment of this invention. It is a figure which shows typically the structure of the SIP server of FIG. It is a figure which shows typically the structure of the telephone terminal of FIG. It is a figure which shows typically the memory content of the registration management information storage part of FIG. It is a figure which shows typically the memory content of the presence information storage part of FIG. It is a figure which shows typically the memory content of the call failure information storage part of FIG. It is an example of the timing chart about transmission / reception of the message in the IP telephone system of FIG. It is an example of the timing chart about transmission / reception of the message in the IP telephone system of FIG. It is an example of the timing chart about transmission / reception of the message in the IP telephone system of FIG. It is an example of the timing chart about transmission / reception of the message in the IP telephone system of FIG.

Explanation of symbols

  100 SIP server, 110, 218 communication unit, 120 registration information management unit, 130 registration management information storage unit, 132, 152 terminal ID, 134, 154 IP address, 136 IP phone number, 140 presence information management unit, 150 presence information storage Unit, 156 presence information, 160 call connection control unit, 170 call failure information storage unit, 172 call failure time, 174 caller side terminal ID, 176 callee side terminal ID, 200 telephone terminal, 210 control unit, 500 network.

Claims (10)

Registration control means for controlling login of the telephone terminal to the IP network;
Session control means for controlling a communication session formed between at least two telephone terminals in an IP network,
The registration control means includes registration information storage means for storing information for specifying each telephone terminal logged into the IP network,
The session control means includes
When information requesting a call from the first telephone terminal to the second telephone terminal is received, and information for identifying the second telephone terminal is not stored in the registration information storage means Call failure information storage means for storing information indicating that session establishment based on a call request from the first telephone terminal to the second telephone terminal has failed;
It is determined whether or not information for specifying the second telephone terminal that is a telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means. Judgment means,
When it is determined by the determination means that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal Transmitting means for transmitting a signal for establishing a session between,
When the information for specifying the second telephone terminal is stored in the registration information storage means continuously for a predetermined time, the information for specifying the second telephone terminal is stored in the registration information storage means. It is determined that
If the determination means determines that the information specifying the second telephone terminal is stored in the registration information storage means, the transmission means continues for a certain period of time after the determination is made. When it is determined that the information identifying the first telephone terminal that is the calling telephone terminal in the information stored in the call failure information storage means is not stored in the registration information storage means, or A determination was made as to whether or not the information for identifying the first telephone terminal that is the calling telephone terminal in the information stored in the call failure information storage means is stored in the registration information storage means a certain number of times. When it is determined that it has not been stored more than a predetermined number of times, information indicating that there has been a call request from the first telephone terminal to the second telephone terminal,
The session control means includes
The information stored in the call failure information storage means is specified when the amount of information stored in the call failure information storage means exceeds a predetermined amount or after being stored in the call failure information storage means Erasing means for erasing when the time of elapses,
SIP server further comprising notification means for notifying the calling telephone terminal of the information erased by the erasure means from the call failure information storage means that the information is erased. Registration control means for controlling login of the telephone terminal to the IP network;
Session control means for controlling a communication session formed between at least two telephone terminals in an IP network,
The registration control means includes registration information storage means for storing information for specifying each telephone terminal logged into the IP network,
The session control means includes
When information requesting a call from the first telephone terminal to the second telephone terminal is received, and information for identifying the second telephone terminal is not stored in the registration information storage means Call failure information storage means for storing information indicating that session establishment based on a call request from the first telephone terminal to the second telephone terminal has failed;
It is determined whether or not information for specifying the second telephone terminal that is a telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means. Judgment means,
When it is determined by the determination means that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal A transmission means for transmitting a signal for establishing a session between them.   When the information for specifying the second telephone terminal is stored in the registration information storage means continuously for a predetermined time, the information for specifying the second telephone terminal is stored in the registration information storage means. The SIP server according to claim 2, wherein the SIP server determines that it has been stored in the server.   The transmission means is stored in the call failure information storage means when the determination means determines that the information specifying the second telephone terminal is stored in the registration information storage means When it is determined that the information specifying the first telephone terminal that is the calling telephone terminal in the information is not stored in the registration information storage means, the second telephone terminal receives the first telephone terminal. 4. The SIP server according to claim 2, wherein information indicating that a call request has been made is transmitted from the SIP server.   The transmission means continues for a certain period of time after the determination means determines that the information specifying the second telephone terminal has been stored in the registration information storage means, and the first telephone terminal The information indicating that there is a call request from the first telephone terminal is transmitted to the second telephone terminal when it is determined that the information specifying the information is not stored in the registration information storage means. 4. The SIP server according to any one of 4.   The transmission means determines that the information specifying the first telephone terminal is stored in the registration information storage means after the determination means determines that the information specifying the second telephone terminal is stored in the registration information storage means. Whether or not the information is stored in the registration information storage means is executed a certain number of times, and when it is determined that the information is not stored more than a predetermined number of times, it is issued to the second telephone terminal from the first telephone terminal. 5. The SIP server according to claim 4, wherein information indicating that there has been a call request is transmitted. The session control means includes
Erasure means for erasing the information stored in the call failure information storage means when the amount of information stored in the call failure information storage means exceeds a predetermined amount;
7. The information processing device according to claim 2, further comprising notification means for notifying the calling side telephone terminal of the information erased by the erasure means from the call failure information storage means that the information is erased. SIP server described in 1. The session control means includes
Erasure means for erasing information stored in the call failure information storage means when a specific time has elapsed since being stored in the call failure information storage means;
7. The information processing device according to claim 2, further comprising notification means for notifying the calling side telephone terminal of the information erased by the erasure means from the call failure information storage means that the information is erased. SIP server described in 1. A SIP server control method comprising: a registration control unit that controls login of a telephone terminal to an IP network; and a session control unit that controls a communication session formed between at least two telephone terminals in the IP network,
Storing information identifying each telephone terminal logged into the IP network;
Receiving information requesting a call from the first telephone terminal to the second telephone terminal;
Whether the second telephone terminal, which is the telephone terminal on the receiving side of the call request, is logged in when receiving information requesting a call from the first telephone terminal to the second telephone terminal Determining whether or not,
Based on the call request from the first telephone terminal to the second telephone terminal when it is determined that the second telephone terminal that is the telephone terminal on the call receiving side is not logged in Storing information indicating that session establishment has failed;
Determining whether the second telephone terminal, which is the telephone terminal on the incoming call side in the information indicating that the session establishment has failed, is logged in;
When it is determined that the second telephone terminal, which is the telephone terminal on the incoming call side, has logged in, the first telephone terminal and the second telephone terminal are configured to establish a session between them. A method for controlling a SIP server, comprising: transmitting a signal. An IP telephone system comprising a first telephone terminal, a second telephone terminal, and a SIP server connectable to the first and second telephone terminals via an IP network,
The SIP server
Registration control means for controlling login of the telephone terminal to the IP network;
Session control means for controlling a communication session formed between at least two telephone terminals in an IP network,
The registration control means includes registration information storage means for storing information for specifying each telephone terminal logged into the IP network,
The session control means includes
When information requesting a call from the first telephone terminal to the second telephone terminal is received, and information for identifying the second telephone terminal is not stored in the registration information storage means Call failure information storage means for storing information indicating that session establishment based on a call request from the first telephone terminal to the second telephone terminal has failed;
It is determined whether or not information for specifying the second telephone terminal that is a telephone terminal on the incoming call side in the information stored in the call failure information storage means is stored in the registration information storage means. Judgment means,
When it is determined by the determination means that the information specifying the second telephone terminal is stored in the registration information storage means, the first telephone terminal and the second telephone terminal Transmission means for transmitting a signal for establishing a session between them.

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