JP2011228854A - Relay apparatus, communication system and communication monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay apparatus, a communication system, and a communication monitoring system to avoid an unexpected disconnection session in a suspension state.SOLUTION: A termination signal transmission part 303 of an SIP server 30 transmits a session termination signal indicating a session termination to a relay apparatus 20 when receiving an instruction of termination of a session established with respect to a mobile station 10. The relay apparatus 20 monitors the data transmission and reception status with the mobile station 10 by a non-communication monitoring part 204 and has a function to request the SIP server 30 to disconnect the session established in the mobile station 10 based on the data transmission and reception status. When the relay apparatus 20 receives the session termination signal by a termination signal reception part 206, a process termination part 205 controls the non-communication monitoring part 204 to prohibit requesting a session termination.

Description

  The present invention relates to a relay device, a communication system, and a communication monitoring method for relaying data transmitted and received through a communication session established between communication devices.

  Conventionally, as a communication system that establishes a communication session between communication devices using SIP (Session Initiated Protocol) and transmits / receives media data such as voice through the established session, for example, one described in Patent Document 1 is disclosed. is there. This communication system includes a SIP server that manages a session, a media server that stores media data, and a mobile station, and a wireless base station, etc., and the wireless base station functions as a relay device between each device. Relaying data to be sent and received. Here, the data transmitted / received between the respective devices uses a control signal transmitted / received using SIP to control a session and RTP (Real-Time Transport Protocol) / RTCP (RTP Control Protocol). Media data to be sent and received.

JP 2009-140090 A

  By the way, a communication method with a small communication capacity such as satellite communication via a communication satellite may be used for communication between a relay device such as a radio base station and a mobile device. In this case, in order to reduce the data capacity, the relay device removes data such as a header portion from the IP (Internet Protocol) packet of media data transmitted using RTP / RTCP, and data such as voice data. Only the part is transferred to the mobile device. In addition, SDP (Session Description Protocol) information including data transfer destination information and the like is notified in advance from the SIP server to the relay device, and the relay device transfers data such as voice based on the SDP information. ing. In order to remove the header portion of the media data transmitted using RTP / RTCP by the relay device, the termination point on the RTP / RTCP mobile device side becomes a relay device, and the termination point on the SIP mobile device side is the mobile device. It has become. As described above, when the termination point of SIP and RTP / RTCP (end point on the mobile device side) is different, the relay device that is the termination point of RTP / RTCP is connected to the mobile device based on the SDP information notified from the SIP server. Media data is relayed to and from the media server.

  Here, using the above communication system having different termination points of SIP and RTP / RTCP, for example, in a state in which the mobile device and the telephone set A are performing call communication via the relay apparatus, the telephone set B sets the relay apparatus. The mobile device is connected to the mobile device via the mobile phone, and call communication between the mobile device and the telephone B is started (so-called call waiting). At this time, the telephone set A is put on hold with a session established with the mobile device. Thereafter, when the call with the telephone set B is terminated, the mobile station requests the SIP server to end the session with the telephone set B, and further requests to resume communication with the telephone set A to communicate with the telephone set A. Call communication is resumed. However, the mobile device may not immediately request to resume communication with the telephone A. The case where the restart of communication is not requested includes, for example, the case where the user of the mobile device does not operate the communication restart button of the mobile device.

  At this time, since the telephone set A is in a hold state, communication using RTP / RTCP is not performed at all in the session between the mobile device and the telephone set A. Here, when the non-communication state in which data such as voice is not transmitted / received between the mobile device and the relay device is continued for a predetermined time or longer, the relay device is abnormal in the state where the non-communication state continues for the predetermined time or longer. Therefore, RTP non-communication monitoring is performed in which a request for disconnecting a session established in the mobile device is made to the SIP server. For this reason, when the mobile device does not immediately request resumption of communication with the telephone A in the hold state, the session between the mobile device and the telephone A in the hold state is disconnected by the RTP non-communication monitoring of the relay device. That is, there is a problem that the telephone set A and the mobile station are disconnected unexpectedly even though the telephone set A desires to resume communication with the mobile unit and waits in a suspended state.

  Therefore, an object of the present invention is to provide a relay device, a communication system, and a communication monitoring method that can prevent a session such as a hold state from being unexpectedly disconnected.

  The present invention specifies a data transmission destination based on data transmission destination information received from a session management apparatus that manages a communication session established between communication apparatuses, and relays data transmitted and received through the session. A non-communication monitoring, which is a relay device, monitors a data transmission / reception state with the communication device, and requests the session management device to disconnect a session established in the communication device based on the data transmission / reception state Means for receiving a session end signal indicating the end of the session established for the communication device, and when the session end signal is received by the end signal receiving means, It is determined whether another session is established for the communication device that has been terminated, and the communication device If the session has been established, characterized in that it comprises a processing stopping means for controlling to prohibit a request for disconnection of said other sessions by the non-communication monitoring means.

  In addition, the present invention specifies a data transmission destination information based on data transmission destination information received from a session management apparatus that manages a communication session established between communication apparatuses, and relays data transmitted and received through the session A communication monitoring method in the relay device that performs the monitoring of data transmission / reception status with the communication device, and sends a session disconnection request established to the communication device to the session management device based on the data transmission / reception status The session end signal is received by the no-communication monitoring step, the end signal receiving step for receiving a session end signal indicating the end of the session established for the communication device, and the end signal receiving step. When another session is established for the communication device for which the session is terminated A process stop step for controlling to prohibit the disconnection request of the other session by the no-communication monitoring step when the other session is established in the communication device; It is characterized by providing.

  The relay device according to the present invention monitors the data transmission / reception state with the communication device by the no-communication monitoring means, and sends a session disconnection request established to the communication device to the session management device based on the data transmission / reception state. Has the function to perform. Therefore, when the relay device receives a session end signal indicating the end of the session established with respect to the communication device by the end signal receiving means, the processing stop means sends another process to the communication device whose session is ended. It is determined whether or not a session has been established, and when another session is established in the communication apparatus, control is performed so as to prohibit a disconnection request for another session by the non-communication monitoring unit. Thereby, for example, even if communication through other sessions among a plurality of sessions established in the communication device is in a no-communication state, a process for requesting the communication device to disconnect the established session is performed. Since it is prohibited by the processing stop means, it is possible to prevent other sessions from being unexpectedly disconnected. Specifically, even if the communication device and the communication partner through another session are on hold, and the request to resume communication with the communication device on hold is delayed, the other session is expected. It is possible to prevent cutting without being performed.

  Note that the end signal receiving means of the relay device preferably receives the session end signal from the session management device. Since the session management device manages the session and grasps the establishment and disconnection of the session, the session end signal can be easily acquired from the session management device.

  The present invention also provides a session management device that manages a communication session established between communication devices, and a data transmission destination information received from the session management device to identify a data transmission destination and through the session A relay device that relays data to be transmitted and received, wherein the session management device receives the instruction to end the established session for the communication device, and An end signal transmission unit configured to transmit a session end signal indicating the end of a session to the relay device, wherein the relay device monitors a data transmission / reception state with the communication device, and based on the data transmission / reception state, Non-communication monitoring means for requesting the session management device to disconnect the session established in the communication device, and the termination An end signal receiving means for receiving the session end signal transmitted from the signal transmitting means, and when the session end signal is received by the end signal receiving means, the communication apparatus for which the session is ended A session is established, and when the other session is established in the communication device, control is performed to prohibit the disconnection request of the other session by the non-communication monitoring means. And a processing stop means.

  The present invention also provides a session management device that manages a communication session established between communication devices, and a data transmission destination information received from the session management device to identify a data transmission destination and through the session A communication monitoring method in a communication system including a relay device that relays data to be transmitted and received, wherein the session management device instructs the communication device to end the established session. When received, an end signal transmission step of transmitting a session end signal indicating the end of the session to the relay device, and the relay device monitors a data transmission / reception state with the communication device, and enters a data transmission / reception state. No communication for requesting the session management apparatus to disconnect the session established based on the communication apparatus A completion signal receiving step in which the relay device receives the session end signal transmitted in the end signal transmission step; and the relay device receives the session end signal in the end signal reception step. Determining whether or not another session is established for the communication device for which the session has been terminated, and in the case where the other session is established for the communication device, the no-communication monitoring step And a process stop step for controlling so as to prohibit the disconnection request of the other session.

  In the communication system according to the present invention, when the end signal transmission unit of the session management apparatus receives an instruction to end the established session with respect to the communication apparatus, the session end signal is transmitted to the relay apparatus. . The relay device has a function of monitoring the data transmission / reception state with the communication device by a non-communication monitoring unit, and making a session disconnection request to the session management device established in the communication device based on the data transmission / reception state. Have. Therefore, when the relay device receives the session end signal transmitted from the end signal transmitting unit by the end signal receiving unit, the processing stop unit determines whether another session has been established for the communication device whose session has been ended. If another session is established in the communication device, control is performed so as to prohibit the disconnection request of the other session by the non-communication monitoring means. Thereby, for example, even if communication through other sessions among a plurality of sessions established in the communication device is in a no-communication state, a process for requesting the communication device to disconnect the established session is performed. Since it is prohibited by the processing stop means, it is possible to prevent other sessions from being unexpectedly disconnected. Specifically, even if the communication device and the communication partner through another session are on hold, and the request to resume communication with the communication device on hold is delayed, the other session is expected. It is possible to prevent cutting without being performed.

  According to the present invention, it is possible to prevent a session in a suspended state or the like from being disconnected unexpectedly.

It is a figure which shows the whole structure of a communication system. It is a hardware block diagram of a relay apparatus. It is a figure which shows the flow of the data between each node.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a communication system to which a relay device, a communication system, and a communication monitoring method according to the present invention are applied will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(Overall configuration of communication system 1)
The overall configuration of the communication system 1 according to the embodiment will be described. FIG. 1 is a diagram illustrating an overall configuration of a communication system. The communication system 1 shown in FIG. 1 performs communication using SIP, and a mobile device 10 (communication device) and a mobile device 40 (SIP UA (SIP User Agent)) by a SIP server 30 (session management device): A communication session between the mobile device 10 and the mobile device 50 (SIP UA: communication device) is established, and data can be transmitted and received between the mobile devices through the established session. Yes. Further, the communication system 1 includes a relay device 20 that relays data transmitted and received between the SIP server 30 and the mobile devices 40 and 50 and the mobile device 10 through a session. The mobile device 10 can establish a plurality of sessions at the same time, and can perform a call waiting operation for performing call communication by switching these sessions.

  Note that a communication network is established between the mobile device 10 and the relay device 20 by satellite communication via a communication satellite (not shown), and between the relay device 20 and the SIP server 30 and the mobile devices 40 and 50 is wired or the like. Assume that an IP packet communication network is constructed. In addition, voice communication is performed between the mobile device 10 and the mobile device 40 and between the mobile device 10 and the mobile device 50, and voice data including data related to voice is transmitted between the mobile devices. Shall be sent and received.

  The SIP server 30 includes a call control unit 301 that controls establishment or disconnection of a session, and SDP information transmission that transmits to the relay device 20 SDP information (data transmission destination information) that is used when the relay device 20 transfers data. When the session established with the unit 302 and the mobile device 10 is terminated, a termination signal transmission unit 303 (end signal transmission unit) transmits a session termination signal indicating that the session is terminated to the relay device 20. And.

  For example, when establishing a communication session between the mobile device 10 and the mobile device 40, the call control unit 301 transmits a control signal for controlling the session to the mobile device 40 using SIP, and further uses SIP. To the mobile device 10 via the relay device 20. Further, when establishing a session, the call control unit 301 generates SDP information in which the address information of both mobile devices with which the session is established is associated with information for identifying the session. The call control unit 301 transmits the generated SDP information to the mobile devices 10 and 40 using SIP together with the control signal. The address information included in the SDP information is address information used for transmitting / receiving voice data transmitted / received by telephone communication. The SDP information further includes codec (CODEC) information of audio data, for example.

  By transmitting and receiving the session control signal, a communication session is established between the mobile device 10 and the mobile device 40, and the mobile device 10 and the mobile device 40 can transmit and receive audio data through the established session. it can. As will be described in detail later, audio data is transmitted / received between the mobile device 40 and the relay device 20 using RTP / RTCP. Only data (hereinafter referred to as audio body data) is transmitted and received.

  Further, the call control unit 301 outputs the generated SDP information to the SDP information transmission unit 302.

  Further, when the session ends, that is, when there is a session end request (for example, “BYE (session end request)” signal, etc.) from the mobile device 10 or the like, the call control unit 301 identifies the session to be ended. The session end signal including the identification information is generated, and the generated session end signal is output to the end signal transmission unit 303. Note that when establishing a session, the call control unit 301 grasps a terminal device of data transmitted / received using SIP or RTP / RTCP. For this reason, the call control unit 301 uses the address information of the device (in this case, the relay device 20 (described later in detail)) that terminates RTP / RTCP for the session for which the termination request has been made, as the session information. This is added to the end signal and output to the end signal transmitting unit 303.

  When receiving the SDP information from the call control unit 301, the SDP information transmission unit 302 transmits the received SDP information to the relay device 20 using SIP.

  When receiving the session end signal from the call control unit 301, the end signal transmission unit 303 sends the end signal to the relay device 20 based on the address information of the transmission destination (here, the address information of the relay device 20) added to the session end signal. To send a session end signal.

  The relay device 20 includes an SDP information receiving unit 202 that receives the SDP information transmitted from the SDP information transmitting unit 302 of the SIP server 30, and a session information management unit 203 that stores the SDP information received by the SDP information receiving unit 202. Transfer of data transmitted / received between the mobile device 10 and the SIP server 30 and data transmitted / received between the mobile device 10 and the mobile devices 40 and 50 based on information stored in the session information management unit 203 And a data transfer unit 201 that performs the transfer.

  Further, the relay device 20 includes a non-communication monitoring unit 204 (non-communication monitoring means) that performs processing such as monitoring whether or not data such as voice is being transmitted / received to / from the mobile device 10, and the SIP server 30. The end signal receiving unit 206 (end signal receiving means) that receives the session end signal transmitted from the end signal transmitting unit 303, and the non-communication monitoring unit 204 when the end signal receiving unit 206 receives the session end signal. And a process stop unit 205 (process stop unit) that prohibits the process according to the above. Note that the relay device 20 can be configured by, for example, a wireless control device or a network device.

  When the SDP information receiving unit 202 receives the SDP information from the SDP information transmitting unit 302 of the SIP server 30, the SDP information receiving unit 202 outputs the received SDP information to the session information management unit 203.

  The session information management unit 203 receives the SDP information from the SDP information receiving unit 202 and stores the received SDP information. Note that the session information management unit 203 stores session identification information, address information of both mobile stations in which the session is established, and codec information of audio data transmitted and received through the session in association with each other. ing. When the session information management unit 203 receives a session end signal from the end signal receiving unit 206, which will be described in detail later, the information corresponding to the session identification information included in the session end signal from the stored information ( Session identification information, mobile device address information, codec information, etc.).

  The data transfer unit 201 transfers control signals and SDP information that are transmitted and received using SIP between the SIP server 30 and the mobile device 10 in order to establish a session.

  Here, satellite communication with a small communication capacity is used between the mobile device 10 and the relay device 20. For this reason, the data transfer unit 201 removes data such as the header portion from the IP packet of the voice data addressed to the mobile device 10 transmitted from the mobile devices 40 and 50 through RTP / RTCP, and converts the voice data into a data portion related to the voice. Convert to audio body data that is only. The data transfer unit 201 transfers the converted audio main body data based on the information stored in the session information management unit 203 (here, the address information of the mobile device 10). The data transfer unit 201 refers to the information stored in the session information management unit 203 when the audio data is received, so that the audio data is based on the information on the transmission source of the audio data, the session identification information, and the like. Can be known.

  In addition, the mobile device 10 transmits voice body data, which is only a data portion related to voice, to the relay device 20 when performing call communication with another mobile device. For this reason, when the data transfer unit 201 receives the voice main body data transmitted from the mobile device 10, the information stored in the session information management unit 203 (the address information of the mobile devices 40 and 50 that are transmission destinations and the transmission source). The received voice body data is converted into voice data that is an IP packet based on address information of a certain mobile device 10. The data transfer unit 201 transfers the converted audio data to the mobile device 40 or the mobile device 50 through RTP / RTCP. Note that the data transfer unit 201 refers to the information stored in the session information management unit 203 at the stage when the audio main body data is received from the mobile device 10, so that the data transfer unit 201 is based on the information on the session in which the audio main body data is transmitted Thus, it is possible to grasp information (such as a transmission source and a transmission destination address) for generating voice data that is an IP packet.

  The no-communication monitoring unit 204 monitors the transmission / reception state of the voice main body data between the mobile device 10 and the data transfer unit 201, and is in a non-communication state where the voice main body data is not transmitted / received based on the transmission / reception state of the voice main body data. Is continued for a predetermined time (for example, 10 seconds). The determination of the non-communication state can be performed by monitoring whether or not the data transfer unit 201 is performing data transfer processing.

  In addition, when a plurality of sessions via the relay device 20 are simultaneously established for the mobile device 10, even if the no-communication state in one session is continued for a predetermined time or longer, the other session is in the communication state. If there is, the no-communication monitoring unit 204 determines that the mobile device 10 and the data transfer unit 201 are in a communication state. That is, when a plurality of communication sessions via the relay device 20 are simultaneously established for the mobile device 10, the no-communication monitoring unit 204 is in a no-communication state. When it is continued for a predetermined time or more, it is determined that there is no communication between the mobile device 10 and the data transfer unit 201 for a predetermined time or more.

  In addition, if the state of no communication between the mobile device 10 and the data transfer unit 201 continues for a predetermined time or more, it is considered that a problem has occurred, which is an abnormal state. Therefore, if the no-communication monitoring unit 204 determines that the no-communication state has continued for a predetermined time or more, the disconnection request for all sessions established for the mobile device 10 in the no-communication state is received. To the SIP server 30.

  When the end signal receiving unit 206 receives the session end signal transmitted from the end signal transmitting unit 303 of the SIP server 30, the end signal receiving unit 206 outputs the received session end signal to the processing stop unit 205 and the session information management unit 203.

  When receiving the session end signal from the end signal receiving unit 206, the processing stop unit 205 performs control to prohibit the no-communication monitoring unit 204 from requesting disconnection of the session. The control for prohibiting a session disconnection request is to stop the process of monitoring the communication state of the voice body data between the mobile device 10 and the data transfer unit 201 or to monitor the communication state of the voice body data. For example, a session disconnection request may be prohibited. In this embodiment, it is assumed that monitoring of the no-communication state performed by the no-communication monitoring unit 204 is stopped.

  Specifically, first, the processing stop unit 205 is based on the session identification information included in the session end signal and the information stored in the session information management unit 203, and the mobile device (in this case, the mobile device) Identify machine 10). Then, based on the information stored in the session information management unit 203, the processing stop unit 205 determines whether or not a session other than the session ended for the identified mobile device 10 has been established. Judging.

  When another session is established for the mobile device 10, the processing stop unit 205 monitors the no-communication monitoring unit 204 to monitor the no-communication state between the specified mobile device 10 and the data transfer unit 201. Control to stop. On the other hand, when there is no other session with the mobile device 10, the processing stop unit 205 controls the non-communication monitoring unit 204 because the non-communication monitoring unit 204 does not perform the process of monitoring the non-communication state. Not performed.

  As described above, since the data transfer unit 201 of the relay device 20 removes the header portion of the voice data transmitted using RTP / RTCP, the termination point on the mobile device 10 side of RTP / RTCP is the relay device 20. Thus, the terminal point on the SIP mobile device 10 side is the mobile device 10.

  Here, the hardware configuration of the relay device 20 will be described. FIG. 2 is a hardware configuration diagram of the relay device 20. As shown in FIG. 2, the relay device 20 physically includes a CPU 251, a RAM 252 and a ROM 253 that are main storage devices, an auxiliary storage device 254 such as a hard disk, a communication interface 255 that is a data transmission / reception device such as a network card, and the like. It is configured as a computer system including. Each function of the relay device 20 described above performs communication by operating a communication interface 255 under the control of the CPU 251 by reading predetermined computer software on hardware such as the CPU 251 and the RAM 252 shown in FIG. At the same time, it is realized by reading and writing data in the RAM 252 and the auxiliary storage device 254. Similarly to the relay device 20, the SIP server 30 is also configured as a computer system including a CPU, RAM, ROM, auxiliary storage device, communication interface, and the like. By operating these, each of the SIP servers 30 described above is operated. Function is realized.

(Process of resuming call communication for mobile devices in hold status)
Next, from the state in which the mobile device 10 and the mobile device 40 are performing call communication via the relay device 20, the call communication of the mobile device 40 is put on hold and the call communication between the mobile device 10 and the mobile device 50 is performed. Will be described. After the call communication between the mobile device 10 and the mobile device 50 is terminated, the call communication between the mobile device 10 and the mobile device 40 is resumed. FIG. 3 is a diagram illustrating a data flow between nodes when a call waiting operation is performed. FIG. 3 shows data flowing between the nodes after the state in which the mobile device 10 and the mobile device 40 are performing call communication.

  When a session for call communication between the mobile device 10 and the mobile device 40 is established by the SIP server 30 (step S101), the relay device 20 transmits and receives data transmitted and received between the mobile device 10 and the mobile device 40. Relay is performed (step S102). As described above, the relay device 20 converts the voice data transmitted from the mobile device 40 through RTP / RTCP into voice body data, and the converted voice body data is received from the SIP server 30 in advance as SDP information. To the mobile device 10 through satellite communication. Further, the relay device 20 converts the voice main body data transmitted from the mobile device 10 through satellite communication into IP packet voice data based on the SDP information, and transfers it to the mobile device 40.

  “INVITE: SDP (session establishment request)” in which the mobile device 50 requests establishment of communication (session establishment) with the mobile device 10 while the mobile device 10 and the mobile device 40 are performing communication. A signal is transmitted to the SIP server 30 (step S103). The “INVITE: SDP (session establishment request)” signal transmitted by the mobile device 50 includes address information of the transmission source of the signal, that is, address information of the mobile device 50 (address information for voice data transmission / reception). It is. The SIP server 30 stores the address information of the mobile device 50 included in the received “INVITE: SDP (session establishment request)” signal. In the signal transmitted by the mobile device 50, “SDP” is indicated. This indicates that the “INVITE” signal includes SDP information (hereinafter, SDP in the transmitted / received signal). The same shall apply to the notation).

  When the SIP server 30 receives the “INVITE: SDP (session establishment request)” signal from the mobile device 50, the SIP server 30 transmits an “INVITE: SDP (session establishment request)” signal requesting the mobile device 10 to establish call communication. (Step S104).

  When receiving the “INVITE: SDP (session establishment request)” signal from the SIP server 30, the mobile device 10 displays, for example, on the display screen of the mobile device 10 to prompt connection with the mobile device 50. When the user of the mobile device 10 performs a connection operation with the mobile device 50, the mobile device 10 requests the mobile device 40 that is currently performing call communication to hold the call communication, and a “reINVITE: SDP (hold request)” signal. Is transmitted to the SIP server 30 (step S105). The “reINVITE: SDP (normal end response)” signal transmitted by the mobile device 10 includes address information (address information for transmitting / receiving voice main body data) of the mobile device 10 that is the transmission source of the signal. . The SIP server 30 stores the address information of the mobile device 10 included in the received “reINVITE: SDP (normal end response)” signal.

  When the SIP server 30 receives the “reINVITE: SDP (holding request)” signal from the mobile device 10, the SIP server 30 changes the session state established between the mobile device 10 and the mobile device 40 to an inactive state (call communication is performed). “ReINVITE: SDP (holding request)” signal for changing to the mobile device 40 (step S106). As a result, the mobile device 40 is put on hold (step S107). Specifically, the mobile device 40 is notified of SDP (media information) for connecting to a server (not shown) on the network that stores the hold sound from the SIP server 30, and the connection destination is determined within the same session. As a result of the change, the hold sound is output from the speaker of the mobile device 40. Note that the mobile device 40 itself may output the hold sound from the speaker without connecting to a server on the network that stores the hold sound. After entering the hold state, the mobile device 40 transmits a “200: SDP (hold response)” signal indicating the hold state to the SIP server 30 (step S108).

  When receiving the “200: SDP (holding response)” signal from the mobile device 10, the SIP server 30 transmits the received “200: SDP (holding response)” signal to the mobile device 10 (step S109). When the mobile device 10 receives a “200: SDP (holding response)” signal from the SIP server 30, the mobile device 40 enters a holding state, and a process for establishing a session between the mobile device 10 and the mobile device 50 is performed. A “200: SDP (normal termination response: OK)” signal indicating normal termination is transmitted to the SIP server 30 (step S110).

  When the SIP server 30 receives the “200: SDP (normal end response: OK)” signal from the mobile device 10, the SIP server 30 transmits the received “200: SDP (normal end response: OK)” signal to the mobile device 50 (step S 30). S111). Further, the SIP server 30 identifies the identification information of the session to be established between the mobile device 10 and the mobile device 50, and stored address information of the mobile device 50 and the mobile device 10 (address information for voice data transmission / reception). ) Is transmitted to the relay device 20 (step S112). When receiving the SDP information from the SIP server 30, the relay device 20 transmits a response signal indicating that the SDP information has been received to the SIP server 30 (step S113).

  Thereby, the session information management unit 203 of the relay device 20 associates the address information of the mobile device 10 and the address information of the mobile device 50 with the identification information of the session established between the mobile device 10 and the mobile device 50. Can be remembered.

  Then, a call communication session is established between the mobile device 10 and the mobile device 50 (step S114), and the relay device 20 relays data transmitted and received between the mobile device 10 and the mobile device 50 ( Step S115).

  As described above, from the state in which the mobile device 10 and the mobile device 40 are performing call communication, the mobile device 40 is put on hold, and call communication between the mobile device 10 and the mobile device 50 becomes possible.

  In addition, when the user of the mobile device 10 performs a call communication end operation with the mobile device 50 in a state in which the call communication is performed between the mobile device 10 and the mobile device 50, the mobile device 10 A “BYE (session end request)” signal indicating the end is transmitted to the SIP server 30 (step S116). When the SIP server 30 receives a “BYE (session end request)” signal from the mobile device 10, it transmits this “BYE (session end request)” signal to the mobile device 50 (step S 117) and terminates the SIP server 30. The signal transmission unit 303 transmits a session end signal indicating the end of the call communication with the mobile device 10 to the relay device 20 (step S118: end signal transmission step).

  When the end signal receiving unit 206 of the relay device 20 receives the session end signal transmitted from the SIP server 30, the processing stop unit 205 of the relay device 20 sends another session to the mobile device 10 whose session is to be ended. Determine whether it is established. Here, it is determined that a session with the mobile device 40 is established as another session. Since the session between the mobile device 40 and the mobile device 10 is established, the processing stop unit 205 of the relay device 20 is in a non-communication state between the mobile device 10 and the relay device 20 that is performed by the non-communication monitoring unit 204. (Step S119: no communication monitoring step, end signal receiving step, processing stop step). After stopping the monitoring of the no-communication state, the relay device 20 transmits a response signal indicating that the stopping of the monitoring of the no-communication state has been completed to the SIP server 30 (step S120).

  Further, when receiving the “BYE (session end request)” signal from the SIP server 30, the mobile device 50 performs a session disconnection process with the mobile device 10 (step S 121), indicating that the disconnection processing has ended normally. A “200 (normal end response: OK)” signal is transmitted to the SIP server 30 (step S122). When receiving the “200 (normal end response: OK)” signal from the mobile device 50, the SIP server 30 transmits the “200 (normal end response: OK)” signal to the mobile device 10 (step S123).

  Thereby, the call communication between the mobile device 10 and the mobile device 50 ends. Note that the mobile device 40 is kept on hold, and is waiting for a request instruction to resume call communication from the mobile device 10. Here, since the processing stop unit 205 of the relay apparatus 20 stops the non-communication state monitoring process by the non-communication monitoring unit 204 in step S119, the mobile device 10 requests the mobile device 40 to resume call communication. Even if it is delayed, it is possible to prevent the session between the mobile device 10 and the mobile device 40 in the hold state from being unexpectedly disconnected by the control of the no-communication monitoring unit 204.

  When the call communication between the mobile device 10 and the mobile device 50 is completed, the mobile device 10 displays, for example, on the display screen of the mobile device 10 to prompt the user to resume the connection of the call communication with the mobile device 40. When the user of the mobile device 10 performs an operation for resuming the call communication with the mobile device 40, the mobile device 10 “reINVITE: SDP (session change request)” for resuming the call communication with the mobile device 40. A signal is transmitted to the SIP server 30 (step S124). The “reINVITE: SDP (session change request)” signal transmitted by the mobile device 10 includes address information (address information for transmitting / receiving voice main body data) of the mobile device 10 that is the transmission source of the signal. . The SIP server 30 stores the address information of the mobile device 10 included in the received “reINVITE: SDP (session change request)” signal.

  When the SIP server 30 receives the “reINVITE: SDP (session change request)” signal from the mobile device 10, the SIP server 30 transmits a “reINVITE: SDP (session change request)” signal for resuming the call communication to the mobile device 40 ( Step S125). When the mobile device 40 receives the “reINVITE: SDP (session change request)” signal, the mobile device 40 releases the hold state in the call communication with the mobile device 10 (step S126), and the process for resuming the call communication is completed. “200: SDP (normal end response: OK)” signal is transmitted to the SIP server 30 (step S127). This “200: SDP (normal end response: OK)” signal transmitted by the mobile device 40 includes address information (address information for voice data transmission / reception) of the mobile device 40 that is the transmission source of the signal. Yes. The SIP server 30 stores the address information of the mobile device 40 included in the received “200: SDP (normal end response: OK)” signal.

  When the SIP server 30 receives the “200: SDP (normal end response: OK)” signal from the mobile device 40, it indicates that the call communication resumption process between the mobile device 10 and the mobile device 40 has ended normally. A “200 (normal end response: OK)” signal is transmitted to the mobile device 10 (step S128). Further, the SIP server 30 identifies the identification information of the session to be resumed between the mobile device 10 and the mobile device 40, and the stored address information of the mobile device 10 and the mobile device 40 (address for transmitting / receiving voice main body data). Information) is transmitted to the relay device 20 (step S129). When receiving the SDP information from the SIP server 30, the relay device 20 transmits a response signal indicating that the SDP information has been received to the SIP server 30 (step S130).

  Thereby, the session information management unit 203 of the relay device 20 associates the address information of the mobile device 10 and the address information of the mobile device 40 with the identification information of the session to be resumed between the mobile device 10 and the mobile device 40. Can be remembered. The data transfer unit 201 of the relay device 20 can transfer data based on the information stored in the session information management unit 203.

  Then, a session for call communication between the mobile device 10 and the mobile device 40 is established (step S131), and call communication between the mobile device 10 and the mobile device 40 is resumed. When the call communication between the mobile device 10 and the mobile device 40 is resumed, the audio body data is transmitted and received between the mobile device 10 and the relay device 20. The no-communication monitoring unit 204 terminates the no-communication monitoring when the voice main body data is transmitted / received between the mobile device 10 and the relay device 20, and is transmitted / received between the mobile device 10 and the relay device 20. Monitors the transmission / reception status of audio data.

(Operation and effect of the embodiment)
Then, the effect | action and effect of the communication system 1 concerning this embodiment are demonstrated. According to the communication system 1 of the present embodiment, when the end signal transmission unit 303 of the SIP server 30 receives an instruction to end the established session to the mobile device 10, the session end signal indicating the end of the session is relayed. Transmit to device 20. The relay device 20 monitors the transmission / reception state of data with the mobile device 10 by the no-communication monitoring unit 204, and requests the SIP server 30 to disconnect the session established in the mobile device 10 based on the data transmission / reception state. Has the function to perform. Further, since the relay device 20 is an RTP / RTCP termination point and not a SIP termination point, and does not check the content of the SIP control signal, the relay device 20 does not confirm the content of the SIP control signal. I do not know the state of. For this reason, in the conventional communication system, the no-communication monitoring unit 204 does not transmit / receive data between the mobile device 10 and the mobile device 40 because the mobile device 40 is on hold. However, the mobile device 10 is requested to disconnect the established session.

  Therefore, when the relay device 20 receives the session end signal transmitted from the end signal transmission unit 303 by the end signal reception unit 206, the processing stop unit 205 causes the mobile device 10 whose session is terminated to receive another session. It is determined whether or not the session is established, and when another session is established in the mobile device 10, the non-communication monitoring unit 204 performs control so as to prohibit the disconnection request of the other session. Thereby, for example, even if communication through other sessions among a plurality of sessions established in the mobile device 10 is in a no-communication state, a process for requesting the mobile device 10 to disconnect the established session Since this is prohibited by the processing stop unit 205, it is possible to prevent other sessions from being disconnected unexpectedly. Specifically, the communication partner (mobile device 40) through another session with the mobile device 10 is in a hold state, and a request for restarting communication with the communication partner (mobile device 40) in which the mobile device 10 is on hold is delayed. Even in such a case, it is possible to prevent other sessions from being disconnected unexpectedly.

  In this way, even if the devices that terminate SIP and RTP are different, a call waiting service for call communication can be provided reliably.

  Further, since the SIP server 30 manages the session and grasps the establishment and disconnection of the session, the end signal receiving unit 206 of the relay device 20 easily acquires the session end signal from the SIP server 30. be able to.

  The present invention is not limited to the above embodiments. For example, the mobile device 10 and the relay device 20 are connected by satellite communication, but wireless communication that performs communication other than IP packets, ISDN (Integrated Services Digital Network), or the like may be used.

  In the present embodiment, the case where a communication session is established by SIP has been described. However, the present invention is not limited to this, and other protocols may be used. Also, communication devices other than the mobile devices 10, 40, 50 can be used.

  Further, in this embodiment, the end timing of the stop of the no-communication monitoring performed in step S119 of FIG. 3 is set when the voice main body data is transmitted / received between the mobile device 10 and the relay device 20. The end timing of the stop of non-communication monitoring is not limited to this. For example, in the no-communication monitoring by the no-communication monitoring unit 204, the session disconnection request is made when the no-communication state continues for a predetermined time or longer (for example, 10 seconds). A predetermined time (for example, 10 seconds) may be extended, and a session disconnection request may be made when, for example, a no-communication state continues for 1 minute or 3 minutes. As a result, even if the mobile device 10 is delayed in the request for resuming the call communication to the mobile device 40, the time until the session between the mobile device 10 and the mobile device 40 is disconnected is extended. Call communication can be performed by performing an operation of resuming call communication within the extended time.

  DESCRIPTION OF SYMBOLS 1 ... Communication system 10, 40, 50 ... Mobile station, 20 ... Relay apparatus, 30 ... SIP server, 204 ... No communication monitoring part, 205 ... Process stop part, 303 ... End signal transmission part.

Claims (5)

A relay device that identifies a data transmission destination based on data transmission destination information received from a session management device that manages a communication session established between communication devices and relays data transmitted and received through the session. And
A non-communication monitoring means for monitoring a data transmission / reception state with the communication device, and performing a session disconnection request to the session management device based on the data transmission / reception state;
End signal receiving means for receiving a session end signal indicating the end of the session established for the communication device;
When the session termination signal is received by the termination signal receiving means, it is determined whether another session is established for the communication device for which the session has been terminated, and the communication device receives the other session Processing stop means for controlling to prohibit the disconnection request of the other session by the non-communication monitoring means when a session is established;
A relay device comprising:   The relay apparatus according to claim 1, wherein the end signal receiving unit receives the session end signal from the session management apparatus. A session management device that manages a communication session established between communication devices, and a relay of data transmitted and received through the session by specifying a data transmission destination based on data transmission destination information received from the session management device A communication system including a relay device that performs
The session management device, when receiving an instruction to end the established session for the communication device, includes a termination signal transmission unit that transmits a session termination signal indicating the termination of the session to the relay device,
The relay device is
A non-communication monitoring means for monitoring a data transmission / reception state with the communication device, and performing a session disconnection request to the session management device based on the data transmission / reception state;
An end signal receiving means for receiving the session end signal transmitted from the end signal transmitting means;
When the session termination signal is received by the termination signal receiving means, it is determined whether another session is established for the communication device for which the session has been terminated, and the communication device receives the other session Processing stop means for controlling to prohibit the disconnection request of the other session by the non-communication monitoring means when a session is established;
A communication system comprising: Communication in a relay device that identifies a data transmission destination and relays data transmitted and received through the session based on data transmission destination information received from a session management device that manages a communication session established between communication devices A monitoring method,
A non-communication monitoring step of monitoring a data transmission / reception state with the communication device, and performing a session disconnection request to the session management device established in the communication device based on the data transmission / reception state;
An end signal receiving step of receiving a session end signal indicating the end of the session established for the communication device;
When the session end signal is received by the end signal receiving step, it is determined whether another session is established for the communication device for which the session has been ended, and the communication device receives the other A process stop step for controlling to prohibit the disconnection request of the other session by the no-communication monitoring step when a session is established;
A communication monitoring method comprising: A session management device that manages a communication session established between communication devices, and a relay of data transmitted and received through the session by specifying a data transmission destination based on data transmission destination information received from the session management device A communication monitoring method in a communication system configured to include a relay device,
When the session management device receives an instruction to end the session established for the communication device, an end signal transmission step of transmitting a session end signal indicating the end of the session to the relay device;
The non-communication monitoring step in which the relay device monitors the transmission / reception state of data with the communication device, and requests the session management device to disconnect the session established with the communication device based on the data transmission / reception state When,
An end signal receiving step in which the relay device receives the session end signal transmitted in the end signal transmission step;
When the relay device receives the session end signal in the end signal receiving step, the relay device determines whether another session is established for the communication device in which the session is ended, and the communication A process stop step for controlling to prohibit the disconnection request of the other session by the no-communication monitoring step when the other session is established in the device;
A communication monitoring method comprising:

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