JP2011091589A - System and device for relieving session - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein, in relation to a session where rewriting of a memory of a session during state transition or the like is frequently performed, the state of an actually-used system may not agree with that of a standby system when the actually-used system is changed over to the standby system due to a fault or the like, a redundant gateway (GW) can not relieve the session. <P>SOLUTION: In this system, when the actually-used system of a GW is changed over to the standby system thereof, session connection information is acquired from the content of state notification from an SIP server, the session connection state of the GW is retrieved from a URI of an inquiry source by the GW including a function of continuing session connection of an SIP and inquiry of the state of the session connection from the GW, and the session connection state with an old actually-used system and information required for session connection are subjected to state notification to a new actually-used system of the GW. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a telephone service session recovery method in an IP network, and more particularly to a system and apparatus for recovering session information in the event of a failure of an apparatus that performs session control and management.

  IP (IP: Internet Protocol) telephone based on VoIP (Voice over Internet Protocol) technology, which can make calls at low cost, due to the low price of large capacity lines and relaxation of regulations in the communication industry, The number of IP phone users is increasing. In addition, the conventional communication network is an independent network vertically integrated for each service such as a telephone network, a mobile network, a leased line network, and a broadcasting network. However, in recent years, a plurality of existing networks are integrated into one. There are moves to reduce operational costs. The network after integration is considered to be configured by an IP network, and it is assumed that a conventional public line telephone network (PSTN: Public Switching Telephony Network) is also shifted to a network configured by IP. It is conceivable that the telephone network is IP.

  SIP (Session Initiation Protocol) has been standardized as a protocol used for real-time services such as VoIP (Voice over IP) and instant messaging on the Internet, and has been established as IETF RFC3261 (Non-patent Document 1). In realizing the service, a SIP server having a SIP proxy function and a SIP registration function on the center side, PSTN STM (Synchronous Transfer Mode) voice signal data and IP voice packet, It is necessary to provide a gateway (GW: Gateway) for connecting the PSTN and the IP network by performing mutual control of the communication and session control with the opposite device using SIP.

  The SIP server or GW accepts connection requests from a plurality of terminals and manages the state of communication (hereinafter referred to as a session) with the partner terminal. Therefore, in realizing the system, it is important to design in consideration of its reliability and availability.

  Generally, a hot standby method and a cold standby method are known as techniques for ensuring the reliability and availability of the system. In hot standby, two systems having the same configuration are prepared, one (active system) is operated, and the other (standby system) is in a standby state while performing the same operation. The standby system always maintains the same state as the active system, and when a failure occurs in the active system, processing is immediately taken over by the standby system. On the other hand, in cold standby, two systems having the same configuration are constructed, one of which is operated as usual, and the other is kept on standby without being operated as standby. In this case, when a failure occurs in a system that performs normal operation, the standby system is started and switched to the same state as that of the normal operation system.

  In cold standby, since a standby system is started and switched after a failure occurs, the entire system stop time is increased when a failure occurs. Since there is no need to operate a standby system in normal times, there is an advantage that the cost can be reduced. On the other hand, hot standby is costly because the standby system is always operated, but it is instantaneously switched when a failure occurs, so that there is an advantage that the entire system downtime is shortened and fault tolerance is increased.

  In the field of electronic exchanges, session relief is realized even if an abnormality occurs in a control system device, an external storage device having an active storage system, a standby system, and an area for storing data that must be shared between the systems, and an external storage There has been disclosed a method of providing a changeover switch for switching the connection system of devices to take information transfer and operation synchronization between the systems (for example, see Patent Document 1).

JP-A-5-244260

IETF (internet Engineering Task Force) RFC3261

  Conventional technologies include a hot standby method and a cold standby method, but each has its own problems. In the hot standby method, session relief is performed by duplicating all hardware such as CPU, memory, disk, and network and operating them simultaneously. As a takeover method in the cold standby method, the entire memory contents of the active system are backed up to an external storage device, and the standby system performs session relief by reloading and restarting it.

  However, in both the hot standby method and the cold standby method, for a session in which the memory is frequently rewritten, such as a session in the state transition, when the active system and the standby system are switched due to a failure or the like, the hot standby system is switched to the standby side. There is a case where the state of the copy of the memory or the backup to the external storage device of the cold standby system does not match the state of the active system, and there is a problem that the session during the state transition cannot be relieved.

  In view of the above, an object of the present invention is to provide a method for relieving a session during state transition even when the active system and the standby system are switched due to a failure or the like of the GW.

  A first communication unit that communicates with a voice communication terminal, a second communication unit that communicates with a call connection device that performs call connection of the voice communication terminal, and a call connection device that performs call connection of the voice communication terminal When a communication request is received from a third communication unit and the first communication unit, a first call connection process for performing a call connection process between the call connection device and the voice communication terminal via the second communication unit A second call connection processing unit for performing a call connection process between the call connection device and the voice communication terminal via a third communication unit, and a spare communication unit. A status inquiry unit that inquires about connection information of a call connection process performed by one call connection processing unit, and a status notification processing unit that processes a connection notification notified from the call connection device, the first call connection When a failure occurs in the processing unit, the second call connection processing unit A connection information request message is transmitted by the state inquiry unit via the third communication unit, and call connection processing is resumed based on connection information of the call connection processing acquired by the state notification processing unit. Provided is a communication device and system.

  According to the present invention, even when the GW is switched between the active system and the standby system due to a failure or the like, connection processing can be continuously performed by relieving the session during the state transition.

Figure showing an example of IP telephone network configuration The figure which shows the block structure of the principal part of a SIP server. The figure which shows the block configuration of the principal part of GW The figure which shows the structure of the connection management table of GW (active system). The figure which shows the structure of the connection management table of GW (standby system). The figure which shows the structure of the subscriber management table of a SIP server The figure which shows the structure of the session management information management table of a SIP server. The figure which shows the structure of the connection management table of a SIP server The figure which shows the example of the operation | movement sequence at the time of session relief provision in the case of operate | moving with a fixed IP address in the active system and standby system of GW The figure which shows the SIP process part flow in a SIP server The figure which shows the status inquiry and status notification processing flow in a SIP server The figure which shows the system switching processing flow of the standby system in GW Description example of SIP message between GW and SIP server (SQ101) Description example of SIP message between GW and SIP server (SQ103 / SQ104) Description example of SIP message between GW and SIP server (SQ106) Description example of SIP message between GW and SIP server (SQ108) The figure which shows the structure of the connection management table of GW (standby system). The figure which shows the structure of the subscriber management table of a SIP server The figure which shows the structure of the session management information management table of a SIP server. The figure which shows the structure of the session management information management table of a SIP server. The figure which shows the structure of the session management information management table of a SIP server. The figure which shows the structure of the session management information management table of a SIP server. The figure which shows the structure of the connection management table of a SIP server The figure which shows the example of the operation | movement sequence at the time of session relief provision in the case of operate | moving with a separate IP address in the active system and standby system of GW The figure which shows the status inquiry and status notification processing flow in a SIP server The figure which shows the system switching processing flow of the standby system in GW Description example of SIP message between GW and SIP server (SQ201) Description example of SIP message between GW and SIP server (SQ203 / SQ204) Description example of SIP message between GW and SIP server (SQ208) Description example of SIP message between GW and SIP server (SQ210) Description example of SIP message between GW and SIP server (SQ206) Diagram showing session control protocol data format

  Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration example showing an IP telephone network when SIP is used as a session control protocol. In the network, a plurality of IP telephone terminals 1 (1-2A, 2B), a SIP server 2, L2SW 3 (3-1, 3) for connecting each IP telephone terminal 1 and the router (R) 4 (4-1 to 3). 2) and an analog telephone terminal used in the PSTN, ISDN terminals (1-1A, 2B), and a GW 5 that performs mutual conversion between PSTM STM voice signal data and IP voice packets.

  The IP telephone terminal 1 (1-2A, 2B) corresponds to a telephone capable of making a voice call on the IP network. The SIP server 2 is a device that plays the role of a conventional telephone exchange on an IP network such as the Internet. (R) 4 (4-1 to 3) and L2SW3 (3-1 and 2) are devices for transferring data on the IP network. The GW 5 is a device used to connect an analog telephone end to the IP network.

  When communication is performed between telephone terminals, registration is first made from the calling terminal 1-1A to the SIP server 2. Next, in order to make a call with the communication partner to the SIP server 2, connection control is performed using a SIP message via the SIP server 2. After the session connection is completed, the calling terminal 1-1 A and the called terminal 1- A call is made between 2B. FIG. 2 is a block diagram showing the main part of the SIP server 2.

  The SIP server 2 mainly includes a SIP processing unit 20, a line IF 21, a control unit 22, a state inquiry processing unit 23, a connection management table 24, a session connection information management table 25, and a subscriber management table 26. The SIP processing unit 20 mainly performs SIP REGISTER processing (F21), connection / disconnection registration processing (F22), SUBSCRIBE reception processing (F23), and NOTIFY transmission processing (F24).

  The line IF 21 is an interface unit with the network, and transmits and receives a call control protocol for communicating with the GW 5 and the IP telephone terminal 1-2A. The state inquiry processing unit 23 searches the URI 710 of the session connection information management table 25 from the state inquiry message received from the device connected to the SIP server 2 using the message source address 2220 as a search key, and the corresponding URI 710 A status notification message is generated from the table information, and the generated status notification message is transmitted to the transmission source of the status inquiry message.

  The connection management table 24 has a session connection management table, and manages connection start time, disconnection time, caller information, and callee information necessary for billing. The session connection information management table 25 manages a series of states of one session from a session connection request to a disconnection request. The subscriber management table 26 manages a telephone number and an address of a device that accommodates the telephone number. The control unit 22 controls the SIP processing unit 20, the line IF 21, the status inquiry processing unit 23, the connection management table 24, the session connection information management table 25, and the subscriber management table 26 in the SIP server 2.

  FIG. 3 is a block diagram showing the main part of the GW 5. The GW 5 is a device for connecting an analog telephone terminal or an ISDN terminal used in the PSTN to an IP network and making a call via the IP network. In addition to the IP telephone connected to the IP network, the other party may be an analog telephone terminal or ISDN terminal connected via the GW.

  The GW 5 mainly includes a line IF (interface) 31, an active system 30A, and a standby system 30S. The active system 30A includes a control unit 32, a SIP processing unit 33, a VoIP processing unit 34, a connection management table 35, a status inquiry unit 36, a status notification processing unit 37, and an IP line IF 38. The SIP processing unit 33 mainly performs registration processing (F31), connection / disconnection processing (F32), SUBSCRIBE transmission processing (F33), and NOTIFY reception processing (F34).

  The VoIP process 34 decodes the RTP packet received from the IP line IF 38 and outputs TDM data to the telephone line IF 31. Also, the TDM data received from the telephone line IF 31 is converted into an RTP packet, and the RTP packet is output to the IP line IF 38. In the telephone line IF31, decoded TDM signals are output from both the active system 30A and the standby system 30S, so the active system is selected and TDM data is output to an external telephone terminal.

  The connection management table 35 has a session connection management table, and manages caller information, callee information, and session information necessary for the session. The state inquiry unit 36 generates a state inquiry message for inquiring the session state from the new active system to the SIP server 2 when a failure occurs.

  The status notification processing unit 37 receives the status notification message returned from the SIP server 2, extracts session information included in the status notification message, and stores the received session information in an empty entry in the connection management table 35. The control unit 32 controls the SIP processing unit 33, the VoIP processing unit 34, the connection management table 35, the status inquiry unit 36, the status notification processing unit 37, and the IP line IF 38. The standby system 30S has the same configuration as the active system 30A.

  FIG. 4 is a diagram showing an example of the data format of the connection management table 35A for managing the state of the connection processing with the SIP server 2 in the connection / disconnection processing (F32A) of the SIP processing unit 33A of the active system 30A of the GW 5. is there.

  The connection management table 35A is a table for managing the state of call connection processing and voice communication performed via the GW 5.

  The connection management table 35A includes a telephone number that is caller information, an address (IP address) of a device that accommodates the caller's telephone number, and a terminal or GW of the corresponding telephone number identifies a session during session processing. Caller information 410 for storing information (Tag information), a telephone number that is information of the called party, an address (IP address) of a device that accommodates the telephone number of the called party, and a corresponding telephone during session processing Numbered terminal or GW is grouped with called party information 420 for storing information (Tag information) for identifying a session, SIP status 430 indicating the state of SIP connection processing, and a series of connection processing for one session. Identification information (Call-ID 440) for distinguishing from other call sessions and a sequence number that increases each time a new request is issued It consists of CSeq450).

  In this embodiment, description will be made using IP and SIP. For example, the entry 480-1 indicates that the user of the caller information 410 and the user of the callee information 420 use the Call-ID: 222222 @ B and CSeq: 5555 ACK to establish the session and The callee information 420 indicates that the user is talking. The entry 480-2 indicates that the user of the caller information 410 makes a call to the user of the callee information 420, and a session is being established using Call-ID: 111111 @ A and CSeq: 1011 INVITE. This indicates that the user 420 is calling.

  FIG. 5 is a diagram illustrating an example of a data format of the connection management table 35S of the standby system 30S of the GW 5. The content of the data format is the same as that of the active system 30A. The entry 580-1 is in a call state, and since the state has been established, information is copied from the active connection management table 35 A to match the information.

  FIG. 6 is a diagram showing a table configuration of the subscriber management table 26 that manages each subscriber information registered in the SIP server 2 in the REGISTER process (F21) of the SIP processing unit 20 of the SIP server 2. The subscriber management table 26 stores correspondence between telephone numbers and IP addresses allocated to users or telephone terminals participating in the call connection service provided by the SIP server 2.

  When the SIP server 2 plays a role as an exchange, it receives the telephone number of the receiving telephone terminal from the calling telephone terminal, and uses the received telephone number as a search key from the subscriber management table 26 for the receiving telephone terminal. Take out the IP address and forward the call connection message.

  The subscriber management table 26 includes a subscriber telephone number 610 and an address (IP address 630) of a device accommodating the subscriber telephone number 610. In this embodiment, an IP address will be described as an example.

  FIG. 8 shows INVITE, connection registration processing and disconnection registration in session control with the GW 5 and IP telephone terminals 1-2A and 1-2B in the connection / disconnection registration processing (F22) of the SIP processing unit 20 of the SIP server 2. It is a figure which shows the table structure of the connection management table 24 managed by the SIP server 2 by each process of a process. It is a table which manages the information regarding the call connection which the SIP server 2 processes.

  The connection management table 24 stores a connection start time 810, a disconnection time 820, a status 830 indicating the state of session connection processing, a caller's telephone number and the address (IP address) of a device accommodating the corresponding telephone number. It includes information 840 and callee information 850 that stores the phone number of the callee and the address (IP address) of the device that accommodates the phone number.

  FIG. 7 shows session connection information management for managing the state of connection processing with the GW 5 and the IP telephone terminals 1-2A and 1-2B in the connection / disconnection registration processing (F23) of the SIP processing unit 20 of the SIP server 2. It is a figure which shows an example of the data format of the table. The session connection information management table 25 manages which sequence processing is currently being performed for each call connection processing session managed by the connection management table 24 described above, and session remedy in the GW 5 described later. Is used.

  The session connection information management table 25 holds a URI 710 (Uniform Resource Identifier) indicating the location of the device accommodating the terminal, terminal information during the session connection for each URI, a telephone number that is terminal information, and a corresponding The address of the device accommodating the telephone number (IP address), the sender information 720 for storing information (Tag information) for identifying the session by the terminal or GW of the corresponding telephone number during the session processing, An incoming call that stores the telephone number that is information, the address (IP address) of the device accommodating the telephone number, and information (Tag information) for identifying the session by the terminal or GW of the telephone number during session processing User information 730, SIP status 740 indicating the state of SIP connection processing, and one set A series of connection processes of a group is grouped to distinguish it from other call sessions (Call-ID 750), a sequence number (CSeq 760) that increases every time a new request is issued, and held terminal information It consists of a DIR 770 indicating whether it is a caller or a callee.

  In this embodiment, description will be made using IP and SIP. For example, the entry 780-1 indicates that the terminal having the telephone number 045-111-2222 accommodated in the URI: 20.0.0.1 is calling from the terminal having the telephone number 03-5000-1111 to make a call. Show. The SIP Call-ID and CSeq used for the call at this time indicate that Call-ID: 222222 @ B and CSeq: 5555 ACK are used, respectively.

  FIG. 32 is a diagram illustrating an example of a data format of a session control protocol communicated between the GW 5 and the SIP server 2. The data shown in FIGS. 13 to 16 is stored in the data area 2230.

  The data format of the session control protocol includes a transmission destination address 2210 that indicates the address of the transmission destination device, a transmission source address 2220 that indicates the address of the transmission source device, and a data area 2230 that stores information on the session control protocol to be transmitted. The destination address 2210, the source address 2220, and an FCS 2240 (Frame Check Sequence) for detecting an error in data in the data area 2230.

  For example, when the INVITE session control protocol (SQ101 in FIG. 9) is transmitted from the GW 5 to the SIP server 2, the address of the SIP server 2 is stored in the transmission destination address 2210, and the address of the GW 5 is stored in the transmission source address 2220. The data area 2230 stores the message of SQ101 in FIG. The FCS 2240 stores a calculation value calculated by a generator polynomial from information of the transmission destination address 2210, the transmission source address 2220, and the data area 2230.

  Next, how the call connection process is performed in the system of FIG. 1 and how the call connection process that was interrupted in the event of a failure is relieved will be described.

  Specifically, the IP addresses of the telephone terminal 1-1A and the telephone terminal 1-1B connected to the GW 5 are used as the working IP addresses of the GW 5, and the old working system 30A is used even when the standby system is changed to the working system. The operation when the IP address that has been used is used in the new active system 30S will be described.

  FIG. 9 shows an example of an operation sequence at the time of providing session relief in this system. The status inquiry signal for inquiring the status from the new active system 30S in the event of a failure will be described below using SIP SUBSCRIBE as an example. The status notification signal from the SIP server will be described below using SIP NOTIFY as an example. SUBSCRIBE and NOTIFY are examples, and can be realized by performing status inquiry and status notification for other messages.

  FIG. 10 is an example of a flowchart showing an operation flow of the SIP processing unit of the SIP server 2 when providing session relief in the present system. FIG. 11 is an example of a flowchart showing an operation flow of status inquiry and status notification processing when providing session relief in the present system. FIG. 12 is an example of a flowchart showing an operation flow of the new active system 30S when the standby system of the GW 5 at the time of providing session relief in this system is switched to the active system. 13 to 16 are message information of SIP signals communicated between the GW 5 and the SIP server 2. Hereinafter, the operation of the session relief method will be described with reference to FIGS.

  First, when the power of the GW 5, the IP telephone terminal 1-2A, and the IP telephone terminal 1-2B is turned on, a REGISTER request is sent to the SIP server 2 in advance in order to make a call, and the subscriber management table 26 The telephone number 610 and the IP address 630 are registered.

  The telephone number of the called terminal 1-2B is dialed from the calling terminal 1-1A (SQ100). GW5 generates a SIP INVITE request (M131) from the dialed telephone number (M131-1), calling terminal information (M131-2), and GW5 IP address (M131-3) to generate a SIP server 2 (SQ101). The SIP server 2 waits until a SIP message is received and receives a session processing-related SIP message (F101). When the received SIP message is an INVITE request, the SIP server 2 determines that the received SIP message is an INVITE request (F102). The subscriber management table 26 is searched using “0350002222”, which is the value of the recipient information (M131-1) of the INVITE request (M131), as search key information, and the table of the entry 650-n in which “0350002222” is registered. The IP address “IP4 = 11.0.0.2” of the called party is extracted from the inside (F103).

  Further, the SIP server 2 obtains the information on the calling terminal and the called terminal in the connection management table 24 from the information included in the searched IP address of the called party and the INVETE request (M131) from FIG. 8 (a) to FIG. 8 (b). (F104). Specifically, the telephone number “0451111111” (M131-2) in the FROM information of the INVITE request (M131) and the IP address “20.0.0.1” (M131-3) are stored in the connection management table 24 of the SIP server 2. Stored in the sender information 840.

  Further, the telephone number “0350002222” (M131-1) of the TO information of the INVITE request (M131) and the destination IP address “11.0.0.2” (F103) extracted from the subscriber management table 26 are SIP. Stored in the callee information 850 of the connection management table 24 of the server 2. Further, the reception status 830 is set to wait for INVITE reception 180 RINGING.

  Next, the SIP server 2 updates the calling terminal information, the called terminal information and the SIP message information in the session connection information management table 25 from FIG. 7A to FIG. 7B (F105). The session connection information management table 25 stores information using the inquiry source IP address as terminal information in order to search the URI 710 using the inquiry source IP address as search key information at the time of status inquiry.

  Therefore, in one session connection, two pieces of information are managed: entry 780-3 as terminal information of the calling terminal and entry 780-4 as terminal information of the called terminal. Note that the number of entries can be reduced to one by using the terminal information 720 and the connection destination information 730 as the search locations using the inquiry source IP address as search key information.

  The specific method of updating the session connection information management table 25 includes the telephone number “0451111111” (M131-2) of the FROM information of the INVITE request (M131) and the IP address “20.0.0.1” (M131- 3) and the tag information “tag = qqqqqq” (M131-4) are stored in the terminal information 720 of the session connection information management table 25 of the SIP server 2 and the call is stored in the DIR 770 indicating the session connection direction. .

  Further, the telephone number “0350002222” (M131-1) of the TO information of the INVITE request (M131) and the destination IP address “11.0.0.2” (F103) extracted from the subscriber management table 26 are SIP. Stored in the connection destination information 730 of the session connection information management table 25 of the server 2. Call-ID information “111111 @ A” (M131-5) and CSeq information “1011 INVITE” (M131-6) of the INVITE request (M131) are stored in Call-ID 750 and CSeq information 760 of the session connection information management table 25, respectively. sign up. The reception status 740 is registered in the entry 780-3 as INVITE reception 180 RINGING waiting.

  Further, when the registration contents of the terminal information 720 and the connection destination information 730 are exchanged, the entry 780-4 is additionally registered with the contents in which the DIR 770 indicating the session connection direction is changed from an outgoing call to an incoming call. The URI 710 stores the IP address “11.0.0.2” stored in the subscriber management table 26 using the telephone number of the terminal information 720 as search key information. As a result of the above processing, the contents of the entries 780-3 and 780-4 in the session connection information management table 25 are updated from the state shown in FIG. 7A to the state shown in FIG. 7B.

  Next, the SIP server 2 transmits an INVITE request to the called terminal 1-2B using the destination IP address (F106, SQ102). When receiving the INVITE request (SQ102), the called terminal 1-2B returns 180 RINGING to the SIP server 2 (SQ103). The SIP server 2 performs the same process as when an INVITE request (SQ101) is received from the received SIP message.

  At this time, the SIP server 2 does not perform the process of F103 because the received SIP message related to session processing is not INVITE. In addition, since the tag information “tag = 456abc” (M132-1) is added to the TO information of the SIP message from the terminal on the incoming call side in the SIP message of 180 RINGING, the SIP server 2 has a session connection information management table. By updating the tag information of the connection destination information 730 of the entry 780-3 of 25 and the tag information of the terminal information 720 of the entry 780-4 and the SIP status, the session connection information management table 25 is updated as shown in FIG. ) To FIG. 7 (c).

  Similarly, the status of the connection management table 24 is updated, and the connection management table 24 is changed from FIG. 8B to FIG. 8C.

  Next, GW system switching due to a failure or the like will be described. First, the working connection management table 35A of the GW 5 before system switching will be described. The active connection management table 35A of the GW 5 generates a table from the SIP message with the SIP server 2 and the subscriber information previously held in the GW 5. In this embodiment, entry 480-1 and entry 480-2 are registered.

  On the other hand, only the entry 580-1 is registered in the standby connection management table 35S of the GW 5. Since the standby system 30S of the GW 5 does not normally operate, the standby system 30S does not process the SIP message, but the entry 580-1 is a state in which a call is in progress between the calling terminal and the called terminal. Yes, since the state is established, the session information is copied from the connection management table 35A of the active system 30A to make the information consistent. Since the session state is not established in the active system 30A, the entry 580-2 does not copy the state from the active system 30A because the state changes in a short period even if copied from the active system 30A. 580-2 is an empty entry.

  When the active system and the standby system of the GW 5 are switched while the connection management table 35S of the standby system 30S is in the state shown in FIG. 5A, the states of the active system connection management table 35A and the standby system connection management table 35S match. In order to save the session, the state of the standby connection management table 35S needs to be the same as that of the active connection management table 35A (FIG. 5B). Hereinafter, the system switching operation of the GW 5 will be described by taking as an example a case where a failure has occurred when a 180 RINGING SIP message is received from the SIP server 2.

  First, when a failure occurs in the active system 30A of the GW 5, the active system 30A of the GW 5 notifies the standby system 30S of a failure and gives an instruction to switch the active system (SQ105). In the standby system 30S of GW5, when the active system switching instruction is issued from the active system (F121), the active system 30A of GW5 is changed to the standby system, and the standby system 30S is changed to the active system by changing the device state. Switch. In the following description, the standby system before switching that becomes the new active system is described as a new active system 30S, and the active system before switching that becomes the new standby system is described as the old active system 30A.

When the system is switched, the IP address when communicating with the SIP server 2 in the active system 30A is taken over to the new active system 30S, and the old active system 30A has an IP address other than the IP address communicating with the SIP server 2 (F122).
The new active system 30S of the GW 5 inquires of the SIP server 2 about the state when the old active system 30A communicated with the SIP server 2 (F123). The status inquiry is performed by the status inquiry unit 36S of the GW 5, and for example, a status inquiry message is generated by inserting “status request” information (M133-1) indicating the status query in the event information in the SIP SUBSCRIBE message format. (M133), the SUBSCRIBE transmission process F33S transmits a status inquiry message to the SIP server 2 (F123, SQ106). The SIP server 2 returns 200 OK after receiving SUBSCRIBE (SQ107).

  In the SIP server 2, the SUBSCRIBE reception process F23 monitors whether or not the status inquiry message is received from another device (F111). When the status inquiry message is received, the status inquiry processing unit 23 sends the contents of the status inquiry message to the SIP server 2. Notice. The state inquiry processing unit 23 searches the URI 710 of the session connection information management table 25 using the inquiry source IP address as search key information (F112). As a result of the search, if there is no terminal information in the session connection (F113), the inquiry source apparatus is notified that there is no terminal information in the session connection (F115). When there is terminal information during session connection (F113), a state notification of the session connection state is performed.

  The state notification processing is performed by the state inquiry processing unit 23. For example, the “status request” information (M135-1) indicating the state notification for the state inquiry is inserted into the event information in the NOTIFY message format, and the SIP header (M135) is inserted. -2) is generated. Information during session connection is stored in the SIP body (M135-3). In the state inquiry processing unit 23, information during session connection is generated from information registered in the session connection information management table 25.

  For example, in the case of the entry 780-3 in FIG. 7C of the session connection information management table 25, the session connection direction is confirmed from the Dir 770, the terminal information 720 is the calling terminal, and the connection destination information 730 is the incoming call. Confirm that it is a terminal. The content of the status notification includes SIP status 740, caller information, callee information, and Call-ID 750 and CSeq 760 information which are SIP information. First, from the information of “180 RINGING 200 OK waiting” stored in the SIP status 740, the information of “111111 @ A” stored in the Call-ID 750, and the information of “1011 INVITE” stored in the CSeq 660, The sip_status information is generated (M135-4).

  From information, which is caller information, is generated from the telephone number and IP address stored in the terminal information 720 determined to be the calling terminal from Dir 770 and Tag information (M135-5). In the To information as the callee information, To information is generated from the telephone number and IP address stored in the connection destination information 730 determined as the called terminal from the Dir 770 and the Tag information (M135-6).

  The generated SIP_status information (M135-4), From information (M135-5), and To information (M135-6) are used as SIP body (M135-3) information, and the SIP server 2 generates a SIP header (for status notification). M135-2) and the SIP body (M135-3) are sent as one NOTIFY message from the NOTIFY transmission process F24 to the GW 5 as the inquiry source (F114, SQ108). For example, when there are a plurality of terminals connected to the session, the NOTIFY message can be transmitted as many messages as the number of terminals, or information of a plurality of terminals can be included in one NOTIFY message.

  The new active system 30S of GW 5 stands by until there is a status notification from the SIP server (F124). When the NOTIFY reception process F34S receives the status notification message, it returns 200 OK to the SIP server 2 (SQ109). The new active system 30S of the GW 5 delivers the content of the status notification message (M135) to the status notification processing unit 37S, and the status notification processing unit 37S uses the received status notification content (M135) information in FIG. The entry 580-2 which is an empty entry in a) is updated to FIG.

  Specifically, the sender's telephone number, IP address, and Tag information are stored in the sender information 510 from the From information (M135-5) of the status notification message (M135). From the To information (M135-6) of the status notification message (M135), the receiver's telephone number, IP address, and tag information are stored in the receiver information 520.

  Further, by storing the SIP status 530 and SIP information Call-ID 540 and CSeq 550 information from the sip_status information (M135-4) of the status notification message (M135), session information is stored in the empty entry 580-2. Then, the state of FIG. 5A of the connection management table 35S is changed to the state of FIG. 5B of the connection management table 35S, and the state is matched with the connection management table 35A of the former active system 30A (F125).

  The GW 5 compares the operation state in the apparatus from the information in FIG. 5B of the connection management table 35S, and operates normally when the system is not switched, such as whether the sound source can be normally transmitted to the subscriber. It is confirmed whether the content to be executed has been executed (F126). When there is a difference in the operating state (F127), the state in the apparatus is changed to a state that should be originally operated when the system switching has not been executed (F128).

  For example, in the case of the entry 580-2 in FIG. 5B in the connection management table 35S, the SIP status is 180 RINGING, so when receiving 180 RINGING, the GW 5 sends an RBT (ringing sound) to the calling terminal 1-1A. Although it is necessary to send out, RBT (ringing tone) is compared with the status of whether the RBT (ringing tone) is being sent to the calling terminal 1-1A in the new active system 30S. I do.

  By performing the above operation, the GW 5 matches the states of the connection management table 35A and the connection management table 35S, and rescues the session that is connected to the session after the system switchover. After matching the states, the processing up to the disconnection processing of the operation sequences SQ111 to SQ121, which is the same operation as in the normal state, is performed.

  In the second embodiment, unlike the first embodiment, an operation when the standby system is changed to the active system when the IP addresses used in the active system 30A and the standby system 30S are changed will be described.

  FIG. 17 is a diagram illustrating an example of a data format of the connection management table 35S of the standby system 30S of the GW 5. The content of the data format is the same as that of the active system 30A. The entry 1480-1 is in a call state, and since the state has been established, information is copied from the active connection management table 35A to match the information.

  FIG. 18 is a diagram showing a table configuration of the subscriber management table 26 that manages each subscriber information registered in the SIP server 2 in the REGISTER process (F21) of the SIP processing unit 20 of the SIP server 2. In the subscriber management table 26, the subscriber telephone number 1510, the address of the device accommodating the subscriber telephone number 1510 (IP address A1520, IP address B1530), and a plurality of addresses are registered (IP address) A valid IP address 1540 indicating a valid address for A and IP address B).

  The combination of IP address A and IP address B is registered in the device as device information in advance during device operation. A valid IP address is selected from IP address A 1520 and IP address B 1530 by a REGISTER request, and the selected result is the valid IP. Register at address 1540. When receiving INVITE, the valid IP address 1540 is referred to and the valid IP address is used.

  19 to 22 show session connection for managing the state of connection processing with the GW 5 and the IP telephone terminals 1-2A and 1-2B in the connection / disconnection registration processing (F23) of the SIP processing unit 20 of the SIP server 2. It is a figure which shows an example of the data format of the middle information management table. The session connection information management table 25 holds information of the URI 1610 indicating the location of the device accommodating the terminal.

  A plurality of URIs can be registered. For example, two IP addresses of the active system 30A and the standby system 30S are registered. In this registration information, a combination of the IP address of the active system 30A and the IP address of the standby system 30S is registered in the subscriber management table 26. The session connection information management table 25 holds in advance terminal information during session connection in units of URIs, a telephone number that is terminal information, an address (IP address) of a device that accommodates the telephone number, and session processing. The caller information 1620 for storing information (Tag information) for identifying the session by the terminal or GW of the corresponding telephone number, the telephone number that is the connection destination information, and the device accommodating the corresponding telephone number Address (IP address), recipient information 1630 for storing information (Tag information) for identifying a session by the terminal or GW of the corresponding telephone number during session processing, and SIP status 1640 indicating the state of SIP connection processing, Identification information (Call−) for grouping a series of connection processes of one session and distinguishing them from other call sessions D1650) and the terminal information held with the sequence number (CSeq1660) that increases every issuance of new requests consists DIR1670 indicating whether the caller or callee. In this embodiment, description will be made using IP and SIP.

  For example, the entry 1680-1 is issued from the terminal having the telephone number 045-111-2222 accommodated in the URIs: 20.0.0.1 and 20.0.0.10. To the terminal having the telephone number 03-5000-1111. It shows that you are calling and talking. The SIP Call-ID and CSeq used for the call at this time indicate that Call-ID: 222222 @ B and CSeq: 5555 ACK are used, respectively.

  FIG. 23 shows INVITE, connection registration processing and disconnection registration in the session control with the GW 5 and the IP telephone terminals 1-2A and 1-2B in the connection / disconnection registration processing (F22) of the SIP processing unit 20 of the SIP server 2. It is a figure which shows the table structure of the connection management table 24 managed by the SIP server 2 by each process of a process. The connection management table 24 stores a connection start time 1710, a disconnection time 1720, a status 1730 indicating the state of session connection processing, a caller's telephone number and an address (IP address) of a device accommodating the corresponding telephone number. It includes information 1740 and recipient information 1750 that stores the telephone number of the recipient and the address (IP address) of the device that accommodates the relevant telephone number. Next, an operation when the active system is switched to the standby system will be described.

  Specifically, the IP addresses of the telephone terminals 1-1A and 1-1B connected to the GW 5 are the IP addresses 20.0.0.1 of the active system 30A of the GW 5 and the IP addresses 20.0.0.1 of the standby system 30S. The operation when the standby system changes to the active system when the IP address used by the active system changes at 0.10 will be described.

  FIG. 24 shows an example of an operation sequence at the time of providing session relief in this system in this embodiment. From FIG. 9 of the first embodiment, REGISTER (SQ206) and 200 OK (SQ208) indicating failure notification are added. The status inquiry signal for inquiring the status from the new active system 30S in the event of a failure will be described below using SIP SUBSCRIBE as an example. The status notification signal from the SIP server will be described below using SIP NOTIFY as an example. SUBSCRIBE and NOTIFY are examples, and can be realized by performing status inquiry and status notification for other messages.

  FIG. 25 is an example of a flowchart showing an operation flow of status inquiry and status notification processing at the time of providing session relief in the present system. FIG. 26 is an example of a flowchart showing an operation flow of the new active system 30S when the standby system of the GW 5 at the time of providing session relief in this system is switched to the active system. 27 to 31 are message information of SIP signals communicated between the GW 5 and the SIP server 2. Hereinafter, the operation of the session relief method will be described with reference to FIGS. 1 to 4, FIG. 10, and FIGS. 14 to 32.

First, when the power of the GW 5, the IP telephone terminal 1-2A, and the IP telephone terminal 1-2B is turned on, a REGISTER request is sent to the SIP server 2 in advance in order to make a call, and the subscriber management table 26 The valid IP address is registered in the valid IP address 1540 among the IP addresses of the telephone number 1510, the active system 30A and the standby system 30S.
(SIP processing part)
The telephone number of the called terminal 1-2B is dialed from the calling terminal 1-1A (SQ200). The GW 5 generates a SIP INVITE request (M231) from the dialed telephone number (M231-1), calling terminal information (M231-2), and the GW5 IP address (M231-3) to generate a SIP server. 2 (SQ201).

  The SIP server 2 waits until a SIP message is received and receives a session processing-related SIP message (F101). When the received SIP message is an INVITE request, the SIP server 2 determines that the received SIP message is an INVITE request (F102). The subscriber management table 26 is searched using “0350002222” that is the value of the recipient information (M231-1) of the INVITE request (M231) as search key information, and the table of the entry 1550-n in which “0350002222” is registered. The valid IP address 1540 is referred to, and the IP address information on the called party side of “IP4 = 11.0.0.2” of the valid IP address A is extracted from a plurality of IP addresses (F103).

  Further, the SIP server 2 obtains the information of the calling terminal and the called terminal in the connection management table 24 from the information included in the searched IP address of the called party and the INVETE request (M231) from FIG. 23 (a) to FIG. 23 (b). (F104). Specifically, the telephone number “0451111111” (M231-2) of the FROM information of the INVITE request (M231) and the IP address “20.0.0.1” (M231-3) are stored in the connection management table 24 of the SIP server 2. Stored in the sender information 1740.

  Further, the telephone number “0350002222” (M231-1) of the TO information of the INVITE request (M131) and the destination IP address “11.0.0.2” (F103) extracted from the subscriber management table 26 are SIP. Stored in the callee information 1750 of the connection management table 24 of the server 2. Further, the reception status 1730 is set to wait for INVITE reception 180 RINGING.

  Next, the SIP server 2 updates the calling terminal information, the called terminal information, and the SIP message information in the session connection information management table 25 from FIG. 19 to FIG. 20 (F105). The session connection information management table 25 stores information using the IP address of the inquiry source as terminal information in order to search the URI 1610 using the IP address of the inquiry source as search key information at the time of status inquiry.

  Therefore, in one session connection, two pieces of information are managed: information of entry 1680-3 as terminal information of the calling terminal and information of entry 1680-4 as terminal information of the called terminal. It is possible to reduce the number of entries to one by using the terminal information 1620 and the connection destination information 1630 as the search locations using the inquiry source IP address as search key information.

  A specific method for updating the session connection information management table 25 is as follows: the telephone number “0451111111” (M231-2) of the FROM information of the INVITE request (M231) and the IP address “20.0.0.1” (M231- 3) and the tag information “tag = qqqqqq” (M231-4) are stored in the terminal information 1620 of the session connection information management table 25 of the SIP server 2 and the call is stored in the DIR 1670 indicating the session connection direction. .

  Further, the telephone number “0350002222” (M231-1) of the TO information of the INVITE request (M231) and the destination IP address “11.0.0.2” (F103) extracted from the subscriber management table 26 are converted into SIP. Stored in the connection destination information 1630 of the session connection information management table 25 of the server 2. The Call-ID information “111111 @ A” (M231-5) and the CSeq information “1011 INVITE” (M231-6) of the INVITE request (M231) are stored in the Call-ID 1650 and the CSeq information 1660 of the session connection information management table 25, respectively. sign up.

  The reception status 1640 is registered in the entry 1680-3 as INVITE reception 180 RINGING waiting. Further, when the registration contents of the terminal information 1620 and the connection destination information 1630 are exchanged, the entry 1680-4 is additionally registered with the contents in which the DIR 1670 indicating the session connection direction is changed from an outgoing call to an incoming call. The URI 1610 stores the IP address A 1520 and the IP address B 1530 stored in the subscriber management table 26 using the telephone number of the terminal information 1620 as search key information.

  As a result of the above processing, the contents of the entries 1680-3 and 1680-4 in the session connection information management table 25 are updated from the state of FIG. 19 to the state of FIG. Next, the SIP server 2 transmits an INVITE request to the called terminal 1-2B using the destination IP address (F106, SQ202).

  When receiving the INVITE request (SQ202), the called terminal 1-2B returns 180 RINGING to the SIP server 2 (SQ203). The SIP server 2 performs the same process as when an INVITE request (SQ201) is received from the received SIP message. At this time, the SIP server 2 does not perform the process of F103 because the received SIP message related to session processing is not INVITE.

  Also, in the 180 RINGING SIP message, the tag information “tag = 456abc” (M232-1) is added to the TO information of the SIP message from the terminal on the called side, so that the SIP server 2 has a session connection information management table. By updating the tag information of the connection destination information 1630 of the 25 entry 1680-3, the tag information of the terminal information 1620 of the entry 1680-4, and the SIP status, the session connection information management table 25 is changed from FIG. Change to 21. Similarly, the status of the connection management table 24 is updated, and the connection management table 24 is changed from FIG. 23B to FIG. 23C.

  Next, switching between the active system and the standby system of the GW due to a failure or the like will be described. First, the working connection management table 35A of the GW 5 before system switching will be described. The active connection management table 35A of the GW 5 generates a table from the SIP message with the SIP server 2 and the subscriber information previously held in the GW 5. In this embodiment, entry 480-1 and entry 480-2 are registered.

  On the other hand, only the entry 1480-1 is registered in the standby connection management table 35S of GW5. Since the standby system 30S of the GW 5 does not normally operate, the standby system 30S does not process the SIP message, but the entry 1480-1 is a state in which a call is in progress between the calling terminal and the called terminal. Yes, since the state is established, the session information is copied from the connection management table 35A of the active system 30A to make the information consistent. At this time, the telephone terminal 1-1A accommodated in the GW 5 has different IP addresses between the active IP address 20.0.0.0.1 and the standby IP address 20.0.0.10. Then, the IP address is rewritten to the IP address 20.0.0.10. Used in the standby system, and the IP address of the sender information 1410 of the entry 1480-1 is registered.

  Since the session state is not established in the active system 30A, the entry 1480-2 does not copy the state from the active system because the state changes in a short period even if copied from the active system 30A. -2 is an empty entry. When the active system and the standby system of the GW 5 are switched while the connection management table 35S of the standby system 30S is in the state of FIG. 17A, the states of the active system connection management table 35A and the standby system connection management table 35S match. In order to save the session, the state of the standby connection management table 35S needs to be the same as that of the active connection management table 35A (FIG. 17B).

  Hereinafter, the system switching operation of the GW 5 will be described by taking as an example a case where a failure has occurred when a 180 RINGING SIP message is received from the SIP server 2.

  First, when a failure occurs in the active system 30A of the GW 5, the active system 30A of the GW 5 issues a failure notification and a system switching instruction to the standby system 30S (SQ205). In the standby system 30S of the GW 5, when the active system switching instruction is issued from the active system (F220), the active system 30A of the GW 5 is changed to the standby system, and the standby system 30S is changed to the active system by changing the device state. Are switched (F221).

  In the following description, the standby system before switching that becomes the new active system is described as a new active system 30S, and the active system before switching that becomes the new standby system is described as the old active system 30A. In order to notify the SIP server 2 that the new working system 30S of the GW 5 has changed the IP address of the GW 5 from 20.0.0.0.1 to 20.0.0.10. A REGISTER message is generated and transmitted to the SIP server 2 (SQ206, F222).

  When the SIP server 2 receives the REGISTER request (F200), it returns 200 OK (SQ207) and uses the telephone number “0451111111” (M236-1) of the To information described in the REGISTER request as search key information. The telephone number 1510 in the subscriber management table 26 is searched, and the entry information of the corresponding telephone number is updated from FIG. 18 (a) to FIG. 18 (b).

  For example, in the case of the calling terminal 1-1A, since the entry 1550-1 is applicable, the IP address “20.0.0.10” (M236-2) of the To information described in the REGISTER request is registered in advance. Compared to the IP address A1520 and the IP address B1530, the IP address B of the matched IP address “20.0.0.10” is updated to the IP address 1540 as the valid IP address (F205).

  The processing of the REGISTER request is executed for all the subscribers accommodated in the GW 5, and the state of the subscriber management table 26 is changed from the state shown in FIG. 18 (a) to the state shown in FIG. 18 (b).

  Further, in the SIP server 2, since the IP address of the GW 5 is changed from 20.0.0.0.1 to 20.0.0.10.10, the caller information 1740 and the callee information 1750 in the connection management table 24, and the session connection In order to update the entry information of the IP address 20.0.0.0.1 already registered in the terminal information 1620 and the connection destination information 1630 of the medium information management table 25 to the IP address 20.0.0.10. The management table 24 is changed from FIG. 23C to FIG. 23D, and the session connection information management table 25 is changed from FIG. 21 to FIG. 22 (F210).

  The new active system 30S of the GW 5 inquires of the SIP server 2 about the state when the old active system 30A communicated with the SIP server 2 (F223). The status inquiry is performed by the status inquiry unit 36S of the GW 5, for example, by generating “status request” information (M233-1) indicating the status query in the event information in the format of the SUBSCRIBE message and generating a status inquiry message ( M233), the SUBSCRIBE transmission process F33S transmits a status inquiry message to the SIP server 2 (F223, SQ208). The SIP server 2 returns 200 OK after receiving SUBSCRIBE (SQ209).

  In the SIP server 2, the SUBSCRIBE reception processing F23 monitors whether or not the status inquiry message is received from another device (F211). When the status inquiry message is received, the status inquiry processing unit 23 sends the content of the status inquiry message. Notice.

  The state inquiry processing unit 23 searches the URI 1610 in the session connection information management table 25 using the IP address of the inquiry source as search key information (F212). As a result of the search, if there is no terminal information in the session connection (F213), the inquiry source apparatus is notified that there is no terminal information in the session connection (F215). When there is terminal information during session connection (F213), a session connection state is notified.

  The state notification processing is performed by the state inquiry processing unit 23. For example, the “status request” information (235-1) indicating the state notification for the state inquiry is inserted into the event information in the NOTIFY message format, and the SIP header (M235). -2) is generated. Information during session connection is stored in the SIP body (M235-3). In the state inquiry processing unit 23, information during session connection is generated from information registered in the session connection information management table 25.

  For example, in the case of entry 1680-3 of FIG. 22 in the session connection information management table 25, the direction of session connection is confirmed from Dir 1670, terminal information 1620 is the calling terminal, and connection destination information 1630 is the called terminal. Make sure. The content of the status notification includes SIP status 1640, caller information, callee information, and Call-ID 1650 and CSeq 1660 information which are SIP information. First, from the information of “180 RINGING 200 OK waiting” stored in the SIP status 1640, the information of “111111 @ A” stored in the Call-ID 1650, and the information of “1011 INVITE” stored in the CSeq 1660, The sip_status information is generated (M235-4).

  From information, which is caller information, is generated from the telephone number and IP address stored in the terminal information 1620 determined to be the calling terminal from the Dir 1670 and Tag information (M235-5). In the To information as the callee information, the To information is generated from the telephone number and IP address stored in the connection destination information 1630 determined as the called terminal from the Dir 1670 and the Tag information (M235-6). The generated SIP_status information (M235-4), From information (M235-5), and To information (M235-6) are used as SIP body (M235-3) information, and the SIP server 2 generates a SIP header for status notification ( M235-2) and the SIP body (M235-3) are used as one NOTIFY message, and the status notification message is transmitted from the NOTIFY transmission process F24 to the GW 5 as the inquiry source (F214, SQ210).

  For example, when there are a plurality of terminals connected to the session, the NOTIFY message can be transmitted as many messages as the number of terminals, or information of a plurality of terminals can be included in one NOTIFY message.

  The new active system 30S of the GW 5 stands by until there is a status notification from the SIP server (F224). When the NOTIFY reception process F34S receives the status notification message, it returns 200 OK to the SIP server 2 (SQ211). The new active system 30S of the GW 5 delivers the content of the status notification message (M235) to the status notification processing unit 37S, and the status notification processing unit 37S uses the received status notification content (M235) information in FIG. 17 of the connection management table 35S. The entry 1480-2 which is an empty entry in a) is updated to FIG.

  Specifically, the sender's telephone number, IP address, and Tag information are stored in the sender information 1410 from the From information (M235-5) of the status notification message (M235). From the To information (M235-6) of the status notification message (M235), the callee information 1420 stores the telephone number, IP address, and Tag information of the callee. Furthermore, by storing the SIP status 1430 and SIP information Call-ID 1440 and CSeq 1450 information from the sip_status information (M235-4) of the status notification message (M235), session information is stored in the empty entry 1480-2. Then, the state of FIG. 17A of the connection management table 35S is changed to the state of FIG. 17B of the connection management table 35S, and the state is matched with the connection management table 35A of the former active system 30A (F225).

  The GW 5 compares the operation state in the apparatus from the information in FIG. 17B of the connection management table 35S, and operates originally when the system is not switched, such as whether the sound source can be normally transmitted to the subscriber. It is confirmed whether the content to be executed has been executed (F226). If there is a difference in the operating state (F227), the state in the apparatus is changed to a state that should be originally operated when system switching has not been executed (F228).

  For example, in the case of entry 1480-2 in FIG. 17B of the connection management table 35S, since the SIP status is 180 RINGING, the GW 5 sends an RBT (ringing sound) to the calling terminal 1-1A when receiving 180 RINGING. Although it is necessary to send out, RBT (ringing tone) is compared with the status of whether the RBT (ringing tone) is being sent to the calling terminal 1-1A in the new active system 30S. I do. By performing the above operation, the GW 5 matches the states of the connection management table 35A and the connection management table 35S, and rescues the session that is connected to the session after the system switchover. After matching the states, the processing up to the disconnection processing of the operation sequences SQ212 to SQ223, which is the same operation as in the normal state, is performed.

  1: Telephone terminal 2: SIP server 3: L2SW 4: Router 5: GW

Claims (24)

A first communication unit that communicates with the voice communication terminal;
A second communication unit that communicates with a call connection device that performs call connection of the voice communication terminal;
A third communication unit that communicates with a call connection device that performs call connection of the voice communication terminal;
When a communication request is received from the first communication unit, a first call connection processing unit that performs a call connection process between the call connection device and the voice communication terminal via the second communication unit;
A second call connection processing unit for performing a call connection process between the call connection device and the voice communication terminal via the spare third communication unit;
A state inquiry unit for inquiring of the connection information of the call connection processing performed by the first call connection processing unit to the call connection device when a failure occurs;
A status notification processing unit for processing a connection notification notified from the call connection device;
When a failure occurs in the first call connection processing unit, the second call connection processing unit transmits a connection information request message by the state inquiry unit via the third communication unit, and the state notification A communication device that resumes call connection processing based on connection information of call connection processing acquired by a processing unit. A first communication unit that communicates with the voice communication terminal;
A second communication unit that communicates with a call connection device that performs call connection of the voice communication terminal;
A third communication unit that communicates with a call connection device that performs call connection of the voice communication terminal;
When a communication request is received from the first communication unit, a first call connection processing unit that performs a call connection process between the call connection device and the voice communication terminal via the second communication unit;
A second call connection processing unit for performing a call connection process between the call connection device and the voice communication terminal via the spare third communication unit;
A state inquiry unit for inquiring of the connection information of the call connection processing performed by the first call connection processing unit to the call connection device when a failure occurs;
A status notification processing unit for processing a connection notification notified from the call connection device;
When a failure occurs in the first call connection processing unit, the second call connection processing unit transmits a registration request to the call connection device via the third communication unit, and the state inquiry unit A communication apparatus that transmits a connection information request message and resumes the call connection process based on the connection information of the call connection process acquired by the state notification processing unit. The communication device according to claim 1,
When the call connection processing is resumed by the second call connection processing unit, an address used in the second communication unit before the failure occurs is set in the third communication unit. Communication device. The communication device according to claim 2,
When the call connection processing is resumed by the second call connection processing unit, an address different from the address used in the second communication unit before the failure occurs is set in the third communication unit. A communication device. The communication device according to claim 1, wherein:
A connection management table storing connection information in a call connection process by the first call connection processing unit or a call in which a call connection is established;
A communication apparatus that updates the connection management table every time a call connection state changes. The communication device according to claim 5,
In a case where connection information of a call established by call connection processing is stored in the connection management table, the communication apparatus is characterized in that connection information of a call established by the call connection processing is also stored in a spare connection management table. The communication device according to claim 6, wherein
The communication apparatus includes the caller information, the callee information, the call connection status, and the identification information of the call connection. The communication device according to claim 7,
The communication apparatus, wherein the second call connection processing unit performs call connection processing using the spare connection management table when a failure occurs in the first call connection processing unit. The communication device according to claim 1, wherein
The notified connection information of the call connection process includes caller information, callee information, call connection status, and call connection identification information used in the call connection process before the failure occurred. Communication device. The communication device according to claim 9, wherein
The status notification processing unit stores connection information of the received call connection processing in the spare connection management table,
The second call connection processing unit resumes the interrupted call connection processing by using the stored connection information of the call connection processing. The communication device according to claim 1, wherein:
The inquiry is transmitted by a SIP SUBSCRIBE message. The communication device according to claim 11,
The communication information is received by a SIP NOTIFY message. The communication device according to claim 7,
The call connection identification information is CALL-ID and Cseq. The communication device according to claim 2,
The communication apparatus, wherein the registration request is a SIP REGISTER message. A call connection device that performs call connection processing between voice communication terminals,
A communication unit communicating with the voice communication terminal;
A call connection processing unit for performing a call connection process between the voice communication terminals;
A call connection state management table for managing connection information of call connection processing between the voice communication terminals;
A state inquiry processing unit for receiving and processing a connection information request message stored in the call connection state management table;
The call connection state management table stores connection information of the call connection process each time connection information of the call connection process performed by the call connection processing unit via the communication unit is updated.
The state inquiry processing unit, when receiving the stored call connection connection information request message, notifies the request source apparatus of the stored call connection connection information. The call connection device according to claim 15,
The state inquiry processing unit searches the call connection state management table using a transmission source address of the received request message as a search key, and extracts connection information notified to the request source device. . The call connection device according to claim 16, wherein
The state inquiry processing unit searches the state management table during call connection and, when connection information requested by the request source device is not found, notifies the request source device to that effect . The call connection device according to any one of claims 15 to 16, comprising:
The call connection device stored in the call connection status table includes caller information, callee information, call connection status, and call connection identification information. The call connection device according to claim 15 to 18, comprising:
The call connection apparatus, wherein the request message is a SIP SUBSCRIBE message. The call connection device according to claim 15 to 19, comprising:
The call connection device, wherein the notification to the request source device is a SIP NOTIFY message. In a call connection system comprising a communication device that relays call connection processing of voice communication terminals and a call connection device that performs call connection processing between voice communication terminals,
The communication device
A first communication unit that communicates with a voice communication terminal, a second communication unit that communicates with a call connection device that performs call connection of the voice communication terminal, and a call connection device that performs call connection of the voice communication terminal When a communication request is received from a third communication unit and the first communication unit, a first call connection process for performing a call connection process between the call connection device and the voice communication terminal via the second communication unit A second call connection processing unit that performs a call connection process between the call connection device and the voice communication terminal via the spare third communication unit, and the call connection device when the failure occurs. A state inquiry unit that inquires about connection information of call connection processing performed by one call connection processing unit, and a state notification processing unit that processes connection notification notified from the call connection device,
When a failure occurs in the first call connection processing unit, the second call connection processing unit transmits a connection information request message by the state inquiry unit via the third communication unit, and the state notification Resume the call connection process based on the connection information of the call connection process acquired by the processing unit,
The call connection device includes:
A communication unit that communicates with the voice communication terminal; a call connection processing unit that performs a call connection process between the voice communication terminals; and a call connection state management table that manages connection information of the call connection process between the voice communication terminals; A status inquiry processing unit for receiving and processing a connection information request message stored in the call connection status management table,
The call connection status management table stores connection information of the call connection process each time connection information of the call connection process performed by the call connection processing unit via the communication unit is updated. Receives the stored call connection connection information request message and notifies the request source apparatus of the stored call connection connection information. The call connection system according to claim 21, wherein
The state inquiry processing unit of the call connection device searches the call connection state management table using a transmission source address of the received request message as a search key, and extracts connection information notified to the request source device. Call connection system. The call connection system according to claim 22, wherein
The connection information includes caller information, callee information, call connection status, and call connection identification information. The call connection system according to claim 23, wherein
The request message transmitted by the communication device is a SIP SUBSCRIBE message,
The notification transmitted by the call connection device is a SIP NOTIFY message.

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