JP2013219707A - Call control system and redundancy method of information for use in call control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a call control system capable of performing system changeover processing in a short time, when failure occurs in an active system call control server and call control processing is performed while switching to a spare system call control server, and to provide a redundancy method of information for use in call control.SOLUTION: In active system call control server 61 and a spare system call control server 62, event management table information 6111b, 6212b registering partial processing (events) constituting call processing in the order of generation are held, respectively. Upon occurrence of an event, synchronous processing of the event management table information 6111b, 6212b is performed based on the type of the event, and synchronous processing of call processing data 6111a, 6211a is performed, as required. The time required for system switching is shortened by performing the event in both servers.

Description

  The present invention relates to a call control system for controlling session establishment by call control and a method for redundancy of information used for call control.

  Conventionally, SIP (Session Initiation Protocol), which is a communication control protocol, has been developed as a technique for controlling session establishment by call control. This SIP makes it possible to perform media communication such as voice information and video information between user terminals using the IP network while maintaining the high quality, reliability, and stability that the fixed telephone network has. To do.

  Call control by SIP is executed between a subscriber terminal used by an end user and an SIP server that relays communication between the subscriber terminals and between a plurality of SIP servers connected via an IP network.

  In order to establish communication by this call control with high reliability, there is a technology that uses a call control system in which an ACT (active) call control server and an SBY (standby) call control server are made redundant.

  In this redundant call control system, the ACT (active) call control server transfers and stores data related to session establishment to the SBY (standby) call control server at a predetermined timing while performing normal operation processing. Perform synchronization processing.

  By executing the synchronization process in this manner, a switching time (necessary data) when a failure occurs in the ACT (active) call control server and the call control process is switched to the SBY (standby) call control server. Transfer time) can be shortened.

Yusuke Ogata, Daisuke Hara, Kazumasa Matsuo, Yoshiki Emura: A method for reducing call switching server switching time, 2010 IEICE General Conference Proceedings, B-6-15 (Mar. 2010).

  However, even when the synchronization process as described above is executed, at the time of system switching, (i) a process of transferring untransferred data from the ACT (active) system call control server to the SBY (standby) system call control server; (Ii) In the SBY (standby) system call control server (new ACT (active) system call control server), the program is started and stored by creating an instance of the call control application in the heap area. A process for expanding the data and starting execution of the program is required.

  While the processes (i) and (ii) are being executed, the service is still interrupted. Therefore, a technique for further reducing the system switching time by reducing the service interruption time has been desired.

  Therefore, in the present invention, in a call control system in which an ACT (active) call control server and an SBY (standby) call control server are made redundant, a failure occurs in the ACT (active) call control server, and call control processing is performed. Is provided with a call control system capable of executing a system switching process in a short time when switching to an SBY (standby) system call control server, and a method for redundancy of information used for call control. Objective.

  The call control system of the present invention for solving the above problems controls call processing between a plurality of servers, and when a failure occurs in the active call control server operating normally and the active call control server. And a standby call control server that operates after switching to the active system, wherein the active call control server includes first call processing data used for call processing being executed by the own server, and A first data storage unit that stores first event management table information in which bibliographic information including information for specifying each partial process is registered in the order of occurrence of the partial processes constituting the call process with respect to the call processes executed by its own server When the partial processing constituting the call processing is generated based on the signal received from the outside, the first event management table information stored in the first data storage unit is updated with the bibliographic information regarding the generated partial processing. If it is determined that synchronization processing of the first event management table information with the standby call control server is necessary based on the updated bibliographic information, the updated amount of the first event management table information is Generates a transfer request for transfer to the standby call control server, monitors the first event management table information at predetermined time intervals, and identifies a partial process to be executed based on the stored bibliographic information A first event management function unit that transfers the updated portion of the first event management table information to the standby call control server based on the transfer request generated by the first event management function unit, When new call processing data is requested from the standby call control server, the corresponding first call processing data is acquired from the first call processing data storage unit and transferred to the standby call control server. A first synchronization processing function unit that responds to the partial processing generated based on the signal received from the outside, and the partial processing specified by the first event management function unit, the first data storage unit A first call processing function unit that executes the first call processing data stored in the first call processing data, and the standby call control server uses the second call processing used for the call processing being executed by the server itself Second data for storing data and second event management table information in which bibliographic information including information for specifying each partial process is registered in the order of occurrence of the partial processes constituting the call process regarding the call process executed by the server itself When the updated portion of the first event management table information is transferred from the storage unit and the active call control server, the second event management table information stored in the second data storage unit is transferred with the transferred information. Update, update Based on the received information, requests the active call control server for new call processing data necessary for executing the partial processing in the second call processing function unit, and also sends the second event at predetermined time intervals. By monitoring the management table information, specifying a partial process to be executed based on the stored bibliographic information, and requesting new call processing data from the second event management function unit The synchronization processing with the information stored in the active call control server by updating the second call processing data stored in the second data storage unit with the first call processing data transferred in response Of the partial processing specified by the second synchronization processing function unit and the second event management function unit, the partial processing excluding signal transmission processing to an external server is stored in the second data storage unit Second call And having a second call processor that executes by using the data.

  Also, the information redundancy method used for call control according to the present invention controls call processing between a plurality of servers, and when a failure occurs in the active call control server that operates normally and the active call control server. First call processing data used by the active call control server for call processing being executed in the own server, and the own server, in a call control system comprising a standby call control server that operates by switching to the active system The first event management table information in which bibliographic information including information specifying each partial process is registered in the order of occurrence of the partial processes constituting the call process, and the active call control When a partial process constituting a call process occurs based on a signal received from the outside, the server updates the first event management table information stored in the bibliographic information related to the generated partial process, and updates the update. When it is determined that synchronization processing of the first event management table information with the standby system call control server is necessary based on the bibliographic information, the update of the first event management table information is used as the standby system call control. A step of generating a transfer request for transfer to the server; and the active call control server sends an update of the first event management table information to the standby call control server based on the generated transfer request. A transfer step, second call processing data used by the standby call control server for call processing being executed by the own server, and occurrence of partial processing constituting call processing with respect to the call processing executed by the own server Sequentially storing second event management table information in which bibliographic information related to each partial process is registered; and the standby call control server receives the first event management table from the active call control server. When the updated information is transferred, the stored second event management table information is updated with the transferred information, and the active call control server generates based on the signal received from the outside Executing the partial processing using the first call processing data, and the active call control server monitors the first event management table information at a predetermined time interval to store the bibliographic information. Identifying a partial process to be executed based on the active call control server executing the identified partial process using first call processing data stored in the first data storage unit The standby call control server monitoring the second event management table information at predetermined time intervals and specifying a partial process to be executed based on the stored bibliographic information; and Requesting the active call control server for new call processing data required when the system call control server executes the partial process specified by monitoring the second event management table information; and the active system When new call processing data is requested from the standby call control server, the call control server responds by acquiring the corresponding first call processing data and transferring it to the standby call control server And the standby call control server updates the stored second call processing data with the first call processing data transferred in response to requesting the new call processing data. Thus, the step of performing synchronization processing with the information stored in the active call control server, and the standby call control server sends a signal to an external server among the specified partial processes to be executed. The partial process excluding the transmission process, and having and executing by using the second call processing data.

  According to the call control system and the information redundancy method used for call control of the present invention, in the call control system made redundant by the ACT (active) call control server and the SBY (standby) call control server, When a failure occurs in the ACT (active) system call control server and the call control process is switched to the SBY (standby) system call control server and executed, the system switch process can be executed in a short time.

1 is an overall view showing a configuration of a SIP communication system using a call control system according to an embodiment of the present invention. It is a block diagram which shows the structure of the call control system by one Embodiment of this invention. It is a table | surface which shows an example of the event management table information memorize | stored in the call control server of the call control system by one Embodiment of this invention. It is a sequence diagram which shows the operation | movement of the signal reception process performed with the server in the call control system by one Embodiment of this invention. It is a sequence diagram which shows the operation | movement of the signal generation process performed with the server in the call control system by one Embodiment of this invention. It is a sequence diagram which shows the operation | movement of the signal transmission process performed with the server in the call control system by one Embodiment of this invention. It is a sequence diagram which shows the operation | movement of the signal retransmission process by the timer expiration performed with the server in the call control system by one Embodiment of this invention. It is a sequence diagram which shows the operation | movement of the reception process of the call request from the external server performed with the server in the call control system by one Embodiment of this invention. It is a sequence diagram which shows a process when the active system and a backup system are switched in the server in the call control system by one Embodiment of this invention.

  A call control system according to an embodiment of the present invention includes a SIP server to which one or more SIP servers are connected before and after, and a series of processing sequence (process) information set in advance between these SIP servers. By transmitting and receiving a SIP signal according to the above, a call is established and a media communication service can be provided.

<Configuration of SIP Communication System Using Call Control Server According to One Embodiment>
A configuration of a SIP communication system 1 using a call control server according to an embodiment of the present invention will be described with reference to FIG.

  The SIP communication system 1 according to the present embodiment is a proxy server connected to a plurality of subscriber terminals 2A to 2D and the subscriber terminal 2A and the subscriber terminal 2B among these subscriber terminals via the IP network 3. SIP server 4A, SIP server 4B, which is a proxy server connected to subscriber terminal 2C and subscriber terminal 2D via IP network 3, and a plurality of servers on IP network 3 connected to SIP server 4A and SIP server 4B Transfer devices 3A to 3G, relay servers 5A and 5B for relaying between SIP server 4A and SIP server 4B, and call control system 6 connected to SIP server 4A, SIP server 4B, relay server 5B, and the like And media servers 7A and 7B on the IP network 3 connected to the call control system 6The traffic of media information such as audio information and video information is transferred between the subscriber terminals 2A to 2D or between the subscriber terminals 2A to 2D and the media servers 7A and 7B via the transfer devices 3A to 3G on the IP network 3. Transferred between.

  Each of the subscriber terminals 2A to 2D is an IP phone, an HGW (home gateway) or the like used by a subscriber who is a user, and media communication used between subscriber terminals such as voice information and video information using SIP. A function of performing SIP negotiation for performing The subscriber terminals 2A to 2D have a function of performing media communication under signal conditions determined as a result of SIP negotiation.

  The transfer devices 3A to 3G are located in the IP network 3 and transfer media communication traffic between the subscriber terminals 2A to 2D.

  The SIP server 4A is a proxy server that relays the SIP signals of the subscriber terminals 2A and 2B, and the SIP server 4B is a proxy server that relays the SIP signals of the subscriber terminals 2C and 2D. The SIP servers 4A and 4B have a function of relaying SIP negotiations between subscriber terminals and supplementing based on subscriber contract information, and a function of editing a SIP signal according to a rule stored in advance.

  The relay servers 5A and 5B have a function of connecting the SIP server 4A and the SIP server 4B and relaying the SIP signal.

  The call control system 6 includes an ACT (active) call control server 61 and an SBY (standby) call control server 62 constructed as a cluster system as shown in FIG. Based on the subscriber contract information type and the requested service at the server, control of call establishment and disconnection between the SIP servers 4A and 4B is performed, and the media servers 7A and 7B and the subscriber terminals 2A to 2D SIP negotiation is performed so that media communication can be performed. In addition, the SIP signal is edited and the SIP negotiation is relayed to establish a call so that subsequent media communication between the subscriber terminals 2A to 2D can be performed.

  FIG. 1 shows a case where two SIP servers (proxy servers) 4A, 4B, two media servers 7A, 7B, etc. are connected to the call control system 6. It is possible to control the establishment and disconnection of a plurality of calls between these devices.

  At normal times, the ACT (active) call control server 61 operates. When a failure occurs in the ACT (active) call control server 61, the SBY (standby) call control server 62 switches to the active system and operates. To do.

  In the present embodiment, the ACT (active) system call control server 61 and the SBY (standby) system call control server 62 have partial processes constituting a series of call processes, for example, a SIP signal reception process, a SIP signal generation process, and a SIP. The signal transmission process is handled as an event that occurs in the local server.

  As shown in FIG. 2, the ACT (active) system call control server 61 includes a first data storage unit 611, a first event management function unit 612, a first call processing function unit 613, and a first synchronization. The processing function unit 614, the first timer management function unit 615, and the first external connection function unit 616 are included.

  The data storage unit 611 includes first call processing data 6111a used for call processing being executed by the own server 61, and information that can be uniquely specified for each event registered in the order of event occurrence in the own server 61. The first event management table information 6111b in which bibliographic information is listed and stored as event information is stored temporarily, and the information stored in the heap area 6111 is acquired at the timing when the event occurs, It has call processing data 6112a and a synchronization area 6112 stored as event management table information 6112b.

  When an event occurs, the event management function unit 612 updates the event management table information 6112b registered in the heap area 6111 of the data storage unit 611 with the event information of the event that has occurred. When the event management function unit 612 determines that the event management table information synchronization processing with the SBY (standby) call control server 62 is necessary based on the updated event information, the event management table information 6111b is updated. A transfer request for transferring the minutes to the SBY (standby) system call control server 62 is generated. Further, the event management function unit 612 monitors the event management table information 6111b at a predetermined time interval, and specifies an event to be executed based on the stored event information.

  The call processing function unit 613 executes the event specified by the event management function unit 612 using the call processing data 6111a stored in the heap area 6111 of the data storage unit 611.

  Based on the transfer request generated by the event management function unit 612, the synchronization processing function unit 614 updates the event management table information 6112b of the synchronization area 6112 with the updated amount of the event management table information 6111b of the heap area 6111, and The updated information is transferred to the SBY (standby) system call control server 62. The synchronous processing function unit 614 transfers the updated portion of the event management table information, and when new call processing data is requested from the SBY (standby) system call control server 62, the corresponding call processing data 6112a is stored. A response is obtained by acquiring from the synchronization area 6112 of the data storage unit 611 and transferring it to the SBY (standby) system call control server.

  The timer management function unit 615 has a timer function for determining whether or not the elapsed time from the transmission of the SIP signal in the call processing function unit 613 has exceeded a predetermined valid period, and notifies the processing completion notification regarding the transmission of the SIP signal. If it is determined that the valid time has expired and the timer has expired without reception, the event management function unit 612 is requested to register a retransmission signal generation event for executing the signal retransmission.

  The external connection function unit 616 is connected to an external Web application server or the like, and provides a service such as “click to dial” that allows a user to call a terminal that supports SIP by clicking a link on the Web page. The call request transmitted from the connected server is received and the call processing from the IP network 3 to a predetermined subscriber terminal is performed.

  The SBY (preliminary) call control server 62 includes a second data storage unit 621, a second event management function unit 622, a second call processing function unit 623, a second synchronization processing function unit 624, , A second timer management function unit 625 and a second external connection function unit 626.

  The data storage unit 621 lists the second call processing data 6211a used for the call processing being executed by the server 62 and the bibliographic information related to each event registered in the order of event occurrence as the event information. The second event management table information 6211b stored in the heap area 6211 is temporarily stored, and the information stored in the heap area 6211 is acquired at the timing when the event occurs, and the call processing data 6212a and the event management table are acquired. And a synchronization area 6212 stored as information 6212b.

  When an event occurs, the event management function unit 622 updates the event management table information 6212b registered in the heap area 6211 of the data storage unit 621 with the event information of the event that has occurred. Further, the event management function unit 622 updates the event management table information 6212b stored in the synchronization area 6212 of the data storage unit 621 with the updated event management table information transferred from the ACT (active) call control server 61, Further, the event management table information 6211b in the heap area 6211 is updated and expanded. The event management function unit 622 also stores the event management table information 6212b stored in the data storage unit 621 with the transferred information when the updated event management table information is transferred from the ACY (active) call control server 61. Is updated, and the event management table information 6211b of the heap area 6211 is updated and expanded. In addition, the event management function unit 622 requests the ACT (active) call control server 61 for new call processing data required when the call processing function unit 623 executes an event based on the updated information. Further, the event management function unit 622 monitors the event management table information 6211b at a predetermined time interval, and identifies an event to be executed based on the stored event information.

  The call processing function unit 623 uses the call processing data 6211a stored in the heap area 6211 of the data storage unit 621 for events other than the signal transmission processing to the external server among the events specified by the event management function unit 622. Use and execute.

  The synchronous processing function unit 624 is call processing data transferred in response to a request for new call processing data from the event management function unit 622, and the call processing data 6212a and call processing data stored in the data storage unit 621 By updating 6211a, the synchronization processing with the information stored in the ACT (active) call control server 61 is performed.

  The timer management function unit 625 has a timer function for determining whether or not the elapsed time from the time point when the SIP signal should be transmitted in the call processing function unit 623 exceeds a predetermined valid period, and a processing completion notification regarding the SIP signal If it is determined that the valid time has been exceeded and the timer has expired without receiving the message, the event management function unit 622 is requested to register a retransmission signal generation event for executing the signal retransmission.

  The external connection function unit 626 is connected to an external web application server or the like, receives a call request transmitted from the connected server, and uses a service such as click to dial to execute a predetermined request from within the IP network 3 Performs call processing to the subscriber terminal.

<Operation of SIP Communication System Using Call Control Server According to One Embodiment>
In the SIP communication system 1 according to the present embodiment, a SIP signal related to call control is sent from the subscriber terminal 2A or 2B, which is a calling terminal, to the subscriber terminal 2C or 2D via the SIP server 4A, the call control system 6, and the SIP server 4B. Operations of the ACT (active) call control server 61 and the SBY (standby) call control server 62 of the call control system 6 when transmitted are described.

  In the present embodiment, event management table information 6111b stored in the heap area 6111 of the data storage unit 611 of the ACT (active) call control server 61, event management table information 6112b stored in the synchronization area 6112, and SBY (reserved) ) The event management table information 6211b stored in the heap area 6211 of the data storage unit 621 of the system call control server 62 and the event management table information 6212b stored in the synchronization area 6212 have unique events as shown in FIG. Information such as “event ID”, “call ID”, “data ID”, “reception time”, “signal transmission time”, which is bibliographic information including information for specifying the information, is listed and stored as event information. ing.

  In FIG. 3, “event ID” is a number uniquely added to each event that has occurred. In the present embodiment, “event”, which is a partial process of a series of call processing, requires transmission of a signal reception event generated when an external SIP signal is received, and a response signal obtained as a result of analyzing the externally received SIP signal. A response signal generation event generated in such a case, a retransmission signal generation event generated when a response to a signal that has already been transmitted cannot be obtained within a predetermined valid period, and a call processing by a request from an external Web server There are types such as a call signal generation event generated when performing, and a signal transmission event generated when transmitting a signal generated by the ACT (active) system call control server 61, Information for identifying these event types and information indicating the occurrence timing of events are included.

  The “call ID” is a number generated from a Call-ID tag that identifies a call to which the event belongs, a to tag that is information about the receiver, and a from tag that is information about the sender. Used to identify a call.

  The “data ID” is a number including the information indicated by the event ID and the information indicated by the call ID, and is used for specifying data necessary for event processing. As the data ID, a more detailed ID for each event type may be provided.

  The “acceptance time” is time information when event information is registered. Information in the event management table in the SBY (standby) call control server 62 is stored in the ACT (active) call control server 61. It is used to determine whether or not it is the latest one synchronized with the information in the event management table.

  The “signal transmission time” is time information when the generated signal is transmitted to the outside by a signal transmission event.

  FIG. 4 is a sequence diagram showing operations of the ACT (active) call control server 61 and the SBY (standby) call control server 62 when a SIP signal is received from an external SIP server.

  First, in the ACT (active) call control server 61, when a SIP signal is received from an external SIP server (S1), the call processing function unit 613 stores the SIP signal in the heap area 6111 as call processing data 6111a. (S2). In the call processing function unit 613, a new call ID is generated if the SIP signal is related to a new call, and if the SIP signal is related to an existing call, a call ID is specified. Is received by the event management function unit 612.

  Next, the event management function unit 612 issues an event ID related to reception of the SIP signal, and is generated from the event ID, the call ID, the event ID, and the call ID in the event management table information 6111b of the heap area 6111. The data ID is registered as a signal reception event together with the reception time information, and the event management table is updated (S3). At the time of signal reception event registration, it is determined that it is necessary to perform synchronization processing with the event management table information of the SBY (standby) system call control server 62, and the event management function unit 612 moves to the synchronization processing function unit 614. Requests to transfer event information for the updated event management table.

  Next, the event management table information 6112b of the synchronization area 6112 is updated and stored by the synchronization processing function unit 614 with the updated information of the event management table information 6111b stored in the heap area 6111 (S4).

  Next, the updated information of the event management table information 6112b in the synchronization area 6112 is transferred to the SBY (standby) system call control server 62 by the synchronization processing function unit 614 (S5).

  In the SBY (standby) system call control server 62, the synchronization processing function unit 624 updates the event management table information 6212b in the synchronization area of the data storage unit 621 with the updated information transferred from the ACT (active) system call control server 61. Is updated, and the event management table information 6211b of the heap area 6211 is updated, expanded, and stored (S6).

  When the synchronization processing function unit 624 of the SBY (standby) system call control server 62 completes the update based on the updated information, an event management table write completion notification is transmitted to the ACT (active) system call control server 61 ( S7). In the ACT (active) system call control server 61, the next process is stopped and waited until the event management table write completion notification is received and the synchronization process is completed.

  Next, refer to the sequence diagram of FIG. 5 for the operations of the ACT (active) call control server 61 and the SBY (standby) call control server 62 when call processing is executed based on the registered signal reception event. To explain.

  First, the event management function unit 612 of the ACT (active) call control server 61 periodically checks the event management table information 6111b in the heap area 6111 by polling or the like, and performs processing based on the data ID in the event management table information 6111b. Target event information (here, a signal reception event) is taken out and sent to the call processing function unit 613 (S11).

  The call processing function unit 613 starts call processing using the corresponding call processing data 6111a based on the acquired event information (S12).

  On the other hand, also in the event management function unit 622 of the SBY (standby) system call control server 62, the event management table information 6211b in the heap area 6211 is periodically confirmed by polling or the like, and the data ID in the event management table information 6211b is set. Based on this, event information to be processed (signal reception event in this case) is taken out and sent to the synchronization processing function unit 624 (S13).

  The event management function unit 622 determines data necessary for the event processing from among the data in the call processing data 6212a of each event information from the information indicating the event type and the occurrence timing included in the event ID of the acquired event information. Further, it is determined whether or not the necessary data synchronization processing is necessary. Here, since the event type included in the event ID is “signal reception event” and the generation timing is when a signal is received from the outside, synchronization processing of the SIP signal data (received signal data) of the corresponding call processing data 6212a is performed. Is determined to be necessary.

  Then, together with the event ID, data ID, and reception time information related to the signal reception event in the event management table information 6212b, an acquisition request for the received signal data related to the event is sent from the event management function unit 622 to the ACT (current) call control server 61. (S14).

  In the synchronization processing function unit 614 of the ACT (active) call control server 61, it is determined whether or not the acquired event ID, data ID, and reception time information are the latest data, and it is determined that the data is the latest data. When it is determined that the data is not the latest data, the latest data of the requested received signal is taken out from the call processing data 6112a and the SBY (standby) system call is returned. The response is made by being transferred to the control server 62 (S15).

  In the SBY (preliminary) system call control server 62, the call processing data 6212a in the synchronization area 6212 is updated by the synchronization processing function unit 624 with the latest data of the transferred received signal, and the call processing data 6211a in the heap area 6211 is further updated. It is updated, expanded and stored (S16).

  When update of the received signal transferred by the synchronization processing function unit 624 of the SBY (standby) system call control server 62 with the latest data is completed, a transfer data write completion notification is transmitted to the ACT (active) system call control server 61. (S17).

  Further, the call processing function unit 613 of the ACT (active) call control server 61 needs to generate a response signal in the call processing (call processing based on the signal reception event in step S12) executed by receiving the SIP signal from the outside. A response signal is generated and the event management function unit 612 is notified of the response signal generation event and the signal transmission event registration request together with the call ID and data ID (S18).

  The event management function unit 612 issues an event ID based on the notified response signal generation event and signal transmission event registration request, and each response signal generation event is stored in the event management table information 6111b of the heap area 6111. Are registered as signal transmission events (S19). Each of these response signal generation event and signal transmission event information includes the corresponding event ID, call ID, data ID, reception time information, and transmission time information. At this time, the signal transmission time information of the signal transmission event is blank. At this time, the event management table information is not synchronized from the ACT (active) call control server 61 to the SBY (standby) call control server 62.

  On the other hand, the call processing function unit 623 of the SBY (preliminary) call control server 62 starts call processing using the call processing data 6211a updated in step S16 (S20).

  Then, since the call processing is also a signal reception event, it is determined that a response signal needs to be generated and a response signal is generated, and a response signal is generated for the event management function unit 622 along with the call ID and data ID. The registration request for the event and the signal transmission event is notified (S21).

  The event management function unit 622 issues an event ID based on the notified response signal generation event and signal transmission event registration request, and each response signal generation event is stored in the event management table information 6211b of the heap area 6211. And registered as a signal transmission event (S22). Each of these response signal generation event and signal transmission event information includes the corresponding event ID, call ID, data ID, reception time information, and transmission time information. At this time, the signal transmission time information of the signal transmission event is blank.

  Next, processing when the generated response signal is transmitted will be described with reference to the sequence diagram of FIG.

  First, the event management function unit 612 of the ACT (active) call control server 61 detects a transmission signal event to be processed based on the event management table information 6111b in the heap area 6111. Here, among the transmission signal events registered in the event management table information 6111b, a signal transmission event whose signal transmission time information is blank is detected as a transmission signal event to be processed.

  Next, the processing target transmission signal event detected by the event management function unit 612 is notified to the call processing function unit 613 (S31).

  When the signal transmission event to be processed is specified by the notification (S32), the call processing function unit 613 recognizes that it is the ACT (active) call control server 61 (S33), and generates the response generated thereby. It is determined that the signal needs to be transmitted to a predetermined destination SIP server, and transmission processing is executed (S34).

  On the other hand, in the event management function unit 622 of the SBY (preliminary) call control server 62, the signal transmission time information is also blank among the transmission signal events registered in the event management table information 6211b of the heap area 6211. Is detected as a transmission signal event to be processed, and is notified to the call processing function unit 623 (S35).

  At this time, the call processing function unit 623 specifies the signal transmission event to be processed by the notification (S36), but recognizes that it is the SBY (standby) system call control server 62 and not the ACT (working) system. (S37), it is determined that there is no need to transmit the response signal generated thereby, and the transmission process is not executed (S38).

  Returning to the processing of the ACT (active) system call control server 61, the transmission time information at which the transmission processing is executed in step S34 is notified from the call processing function unit 613 to the event management function unit 612 (S39).

  The event management function unit 612 updates the transmission time information of the signal transmission event in the event management table information 6111b with the notified transmission time information (S40). Further, the synchronous processing function unit 614 is requested to transfer the updated transmission time information to the SBY (standby) system call control server 62 (S41).

  Then, the synchronization processing function unit 614 updates the event management table information 6112b of the synchronization area 6112 with the transmission time information updated in the heap area 6111, and further updates the transmission time information updated in the synchronization area 6112 to the SBY (standby) system. It is transferred to the call control server 62 (S42).

  In the SBY (standby) system call control server 62, the synchronization processing function unit 624 manages event management of the synchronization area 6212 of the data storage unit 621 with the updated transmission time information transferred from the ACT (active) system call control server 61. The table information 6212b is updated, and the event management table information 6211b of the heap area 6211 is updated and expanded and stored (S43).

  When the synchronization processing function unit 624 of the SBY (preliminary) system call control server 62 completes updating with the updated event information, an event management table write completion notification related to the transmission signal event is sent to the event management function unit 622. (S44).

  With the processing in steps S1 to S42 described above, the description of processing when a response signal is transmitted to another SIP server in response to a SIP signal received from the outside ends.

  Next, in the present embodiment, ACT (active) when a retransmission signal is generated and transmitted due to the expiration of the SIP retransmission timer without a response signal (ACK signal, etc.) from the previous device that transmitted the signal (PRACK signal, etc.) The operations of the system call control server 61 and the SBY (standby) system call control server 62 will be described with reference to the sequence diagram of FIG.

  First, the elapsed time from the transmission of the SIP signal in the call processing function unit 613 based on the transmission time information of the signal transmission event in the event management table information 6111b by the timer management function unit 615 of the ACT (active) call control server 61. Whether or not a predetermined valid period has been exceeded (S51), and if it is determined that the process has not been received and the valid period has been exceeded in response to the transmitted SIP signal, the timer has expired (S52). The management function unit 612 is requested to register a retransmission signal generation event and a signal transmission event related to the signal retransmission (S53).

  In response to this, the event management function unit 612 issues an event ID related to the registration request for the retransmission signal generation event and the signal transmission event, respectively, and in the event management table information 6111b of the heap area 6111, the retransmission signal generation event, And it is registered as a signal transmission event (S54). Each of these retransmission signal generation event and signal transmission event information includes a corresponding event ID, call ID, data ID, reception time information, and transmission time information. At this time, since the call processing data at the previous transmission / reception when the timer expired is already held in the SBY (standby) system call control server 62, the ACT (active) is used for the retransmission signal generation event and the signal transmission event. ) Synchronization processing of event management table information between the system call control server 61 and the SBY (standby) system call control server 62 is not performed.

  Then, the generated retransmission signal generation process and the signal transmission process from the ACT (active) call control server 61 are executed by the same processes as in steps S11 to S22 and steps S31 to S34 described above (S55). .

  The SBY (preliminary) system call control server 62 executes the same processing as steps S51 to S54, and the signal transmission event is specified as the signal retransmission processing as in steps S35 to S38 (S60). Since it is not an ACT system, transmission to an external server is not performed (S35-S38).

  When signal retransmission processing is executed in steps S55 and S60, processing similar to that in steps S39 to S44 in FIG. 6 is executed, and transmission time information is updated and synchronization processing is performed.

  With the processes in steps S51 to S60, the description of the process when the retransmission signal is generated and transmitted when the timer expires is finished.

  Next, in the present embodiment, in response to a call request from an external web application server or the like, a call is made using a service (for example, “click to dial service”) that calls a predetermined subscriber terminal from within the IP network 3. The operations of the ACT (active) call control server 61 and the SBY (standby) call control server 62 during call processing will be described with reference to the sequence diagram of FIG.

  First, in the external connection function unit 616 of the ACT (active) system call control server 61, when a call request signal for a predetermined subscriber terminal is received from an external Web application server or the like (S71), the external connection function unit 616. Thus, the call request signal is stored as call processing data 6111a in the heap area 6111 (S72). The external connection function unit 616 generates a call ID related to the call request signal, and notifies the event management function unit 612 that the call request signal related to the call ID has been received.

  Next, the event management function unit 612 issues an event ID related to reception of the call request signal, and the event management table information 6111b of the heap area 6111 stores the event ID, the call ID, the event ID, and the call ID. The generated data ID is registered as a signal reception event together with the reception time information, and the event management table is updated (S73). Further, the event management function unit 612 requests the synchronization processing function unit 614 to transfer information for updating the event management table.

  Next, the synchronization processing function unit 614 updates and stores the event management table information 6112b in the synchronization area 6112 with the updated information of the event management table information 6111b stored in the heap area 6111 (S74).

  Next, the information for updating the event management table information 6112b in the synchronization area 6112 is transferred to the SBY (standby) system call control server 62 by the synchronization processing function unit 614 (S75).

  In the SBY (standby) system call control server 62, the synchronization processing function unit 624 updates the event management table information 6212b in the synchronization area of the data storage unit 621 with the updated information transferred from the ACT (active) system call control server 61. Is updated, and the event management table information 6211b of the heap area 6211 is updated, expanded, and stored (S76).

  When the synchronization processing function unit 624 of the SBY (standby) system call control server 62 completes the update based on the updated information, an event management table write completion notification is transmitted to the ACT (active) system call control server 61 ( S77).

  With the processes in steps S71 to S77 described above, the description of the reception process when a call request from an external Web application server or the like is received ends. Thereafter, the processing when the call processing and the synchronization processing of the event management table information are executed based on the registered signal reception event is the same as steps S11 to S22 in FIG. 5, and when signal transmission is performed by this call processing. Since this process is the same as steps S31 to S44 in FIG. 6, a detailed description thereof will be omitted.

  With reference to the sequence diagram of FIG. 9, processing when a failure occurs in the ACT (active) system call control server 61 in a state in which call processing is being executed by the call control system 6 by the above-described processing.

  When a failure occurs in the ACT (active) system call control server 61 and the server is switched from the ACT (active) system to the SBY (standby) system, this system switching information is notified to the event management function unit 612.

  In the event management function unit 612, when the system switching information is acquired (S81), the event management table information 6111b is checked by the event management function unit 612 to detect an untransmitted signal transmission event, and the call processing function unit 613 Notification is made (S82).

  In the call processing function unit 613, an unprocessed signal transmission event is identified and activated by the notification (S83). However, the call processing function unit 613 is an SBY (standby) system call control server 62 and is not an ACT (current system) system. It is recognized (S84), it is determined that it is not necessary to transmit the corresponding response signal, and the transmission process is not executed (S85).

  On the other hand, when the SBY (standby) system call control server 62 or the SBY (standby) system is switched to the ACT (working) system, this system switching information is notified to the event management function unit 622.

  When the system switching information is acquired in the event management function unit 622 (S86), the event management function unit 622 checks the event management table information 6211b to detect an untransmitted signal transmission event, and the call processing function unit 623 Notification is made (S87).

  When an unprocessed signal transmission event is specified by the notification (S88), the call processing function unit 623 recognizes that it is an ACT (active) system (S89) and sends a corresponding response signal to a predetermined response signal. It is determined that transmission to the destination SIP server is necessary, and transmission processing is executed (S90).

  Next, the transmission time information at which the transmission process is executed in step S90 is notified from the call processing function unit 623 to the event management function unit 622 (S91).

  In the event management function unit 622, the transmission time information of the signal transmission event in the event management table information 6211b is updated with the notified transmission time information (S92). Further, the synchronous processing function unit 624 is requested to transfer the updated transmission time information to the SBY (standby) call control server 61 (S93).

  Then, the synchronization processing function unit 624 updates the event management table information 6212b of the synchronization area 6212 with the transmission time information updated in the heap area 6211, and further updates the transmission time information updated in the synchronization area 6212 to the SBY (standby) system. Is transferred to the call control server 61 (S94).

  In the SBY (standby) system call control server 61, the synchronization processing function unit 614 uses the updated transmission time information transferred from the ACT (working) system call control server 62 in the synchronization area 6112 of the data storage unit 611. The event management table information 6112b is updated, and the event management table information 6211b in the heap area 6211 is updated and expanded and stored (S95).

  When the synchronization processing function unit 614 of the SBY (preliminary) call control server 61 completes the update based on the updated event information, the event management function unit 612 is notified of completion of writing to the event management table regarding the transmission signal event. It is sent out (S96). Thereby, the event management function unit 612 recognizes that the processing related to the activated signal transmission event is completed.

  According to the present embodiment described above, each detailed partial process related to call processing (SIP signal reception processing, response signal generation processing, retransmission signal generation processing at time-out, call processing by external request, signal transmission processing, etc.) Each event is handled as an event, and the bibliographic information is managed in the event management table, so that each process can be executed in the SIP server of each ACT system and SBY system in the order of generation. Regardless of (signal analysis result, timer expired, call from external server, etc.), appropriate management according to the execution status of the process becomes possible.

  In addition, new call processing data is transferred from the ACT call control server to the SBY call control server as needed for each event, such as when a SIP signal is received or a call processing occurs due to a request from the outside. When a failure occurs in the ACT call control server by performing the call processing other than the signal transmission process at the same timing as the ACT call control server in the SBY call control server while performing deployment and synchronization Data transfer amount can be reduced, and the switching processing time can be greatly shortened.

  Further, when new call processing data is transferred from the ACT call control server to the SBY call control server as necessary, the necessary call information based on the item information such as the call ID and event ID managed in the event management table is used. Since the synchronization processing is performed by specifying the processing data after specifying it in advance, useless data transfer can be omitted, the amount of data transfer during the synchronization processing can be reduced, and the processing amount can be increased.

In addition, by handling the signal generation event and the signal transmission event as separate events during call processing by the call control server,
(I) The ACT system control server executes the signal generation event and the signal transmission event, while the SBY system call control server executes the signal generation event but does not execute the signal transmission event. Can perform call processing,
(Ii) At the time of system switching, call processing data transfer and signal generation from the old ACT system have been completed, so that signal transmission can be performed by generating only a signal transmission event, thereby reducing processing time at system switching. can do.

  Further, the SBY call control server also synchronizes the signal transmission timing (transmission signal time information) by the ACT control server, so that the signal generation process by the expiration of the response signal timer from the opposite device after the signal transmission. Can be appropriately executed by the SBY call control server, and the processing time at the time of system switching can be shortened.

  At this time, a response signal is generated by both the ACT call control server and the SBY call control server, but the signal transmission process is executed only when the own server is an ACT call control server. If the control server is not executed, it can operate normally with respect to the external SIP server.

DESCRIPTION OF SYMBOLS 1 ... SIP communication system 2A-2D ... Subscriber terminal 3 ... IP network 3A-3G ... Transfer apparatus 4A, 4B ... SIP server 5A, 5B ... Relay server 6 ... Call control system 7A, 7B ... Media server 61 ... ACY (current use) ) System call control server 62 ... SBY (standby) system call control server 611 ... Data storage unit 612 ... Event management function unit 613 ... Call processing function unit 614 ... Synchronization processing function unit 615 ... Timer management function unit 616 ... External connection function Unit 621 ... Data storage unit 622 ... Event management function unit 623 ... Call processing function unit 624 ... Synchronization processing function unit 625 ... Timer management function unit 626 ... External connection function unit 6111, 6211 ... Heap areas 6111a, 6112a, 6211a, 6212a ... Call processing data 6111b, 6112b, 6211b, 6212b ... Vent management table information 6112,6212 ... synchronization area

Claims (5)

An active call control server that controls call processing between a plurality of servers, and a standby call control server that operates by switching to the active system when a failure occurs in the active call control server Call control system,
The active call control server is:
Bibliographic information including information specifying each partial process in the order of occurrence of the partial processes constituting the call process regarding the first call process data used for the call process being executed on the own server and the call process executed on the own server. A first data storage unit for storing the registered first event management table information;
When a partial process constituting a call process occurs based on a signal received from the outside, the first event management table information stored in the first data storage unit is updated with bibliographic information related to the generated partial process, If it is determined that synchronization processing of the first event management table information with the standby call control server is necessary based on the updated bibliographic information, the updated portion of the first event management table information is used for the backup A transfer request for transferring to the system call control server is generated, and the first event management table information is monitored at predetermined time intervals, and a partial process to be executed is specified based on the stored bibliographic information. 1 event management function,
The updated portion of the first event management table information is transferred to the standby call control server based on the transfer request generated by the first event management function unit, and from the standby call control server accordingly When new call processing data is requested, the first synchronous processing responds by acquiring the corresponding first call processing data from the first call processing data storage unit and transferring it to the standby call control server A functional part;
Using the first call processing data stored in the first data storage unit, the partial processing generated based on the signal received from the outside and the partial processing specified by the first event management function unit are performed. A first call processing function unit to execute,
The standby call control server is:
Bibliographic information including information specifying each partial process in the order of occurrence of the partial processes constituting the call process regarding the second call process data used for the call process being executed on the own server and the call process executed on the own server. A second data storage unit for storing the registered second event management table information;
When the updated portion of the first event management table information is transferred from the active call control server, the second event management table information stored in the second data storage unit is updated with the transferred information, Based on the updated information, new call processing data required when the second call processing function unit executes partial processing is requested to the active call control server, and the second call processing data is transmitted at predetermined time intervals. A second event management function unit that monitors event management table information and identifies a partial process to be executed based on the stored bibliographic information;
Update the second call processing data stored in the second data storage unit with the first call processing data transferred in response to a request for new call processing data from the second event management function unit A second synchronization processing function unit for performing a synchronization process with information stored in the active call control server,
Of the partial processing specified by the second event management function unit, partial processing excluding signal transmission processing to an external server is executed using the second call processing data stored in the second data storage unit And a second call processing function unit. The active call control server is:
If it is determined that a predetermined effective time has passed without receiving a processing completion notification after executing the signal transmission partial processing in the first call processing function unit, the first event management function unit retransmits the signal. A first timer management function unit that requests registration of bibliographic information related to the partial processing to be executed;
The first event management function unit registers bibliographic information related to partial processing for executing retransmission of the signal acquired from the first timer management function unit in the first event management table information,
The standby call control server is:
If it is determined that a predetermined effective time has passed without receiving a processing completion notification after the partial processing of signal transmission has been performed by the second call processing function unit, the second event management function unit is caused to retransmit the signal. A second timer management function unit that requests registration of bibliographic information related to the partial process for execution;
The second event management function unit registers, in the second event management table information, bibliographic information related to partial processing for executing retransmission of the signal acquired from the second timer management function unit. Item 4. The call control system according to Item 1. The active call control server is:
An external connection function unit for notifying the first event management function unit of a call request transmitted from an external server;
The first event management function unit registers and updates bibliographic information related to partial processing for executing a call based on the call request acquired from the external connection function unit in the first event management table information. Further, based on the updated bibliographic information, it is determined that information synchronization processing with the standby call control server is necessary, and the updated portion of the first event management table information is used as the standby call control. The call control system according to claim 1, wherein a transfer request for transferring to a server is generated. The second event management function unit of the standby system call control server specifies a signal transmission process which is an unprocessed partial process from the second event management table information when the own server is switched to the active system. The second event management table information is updated with the execution time information of the signal transmission process executed by the second call processing function unit by specification,
The second synchronization processing function unit transfers the execution time information of the signal transmission process to the active call control server switched to the standby system,
The first event management function unit specifies a signal transmission process that is an unprocessed partial process from the first event management table information when the own server is switched to a standby system, and the second synchronization processing function unit 4. The call control system according to claim 1, wherein the first event management table information relating to the identified signal transmission process is updated with the execution time information of the signal transmission process transferred from the call control system. 5. An active call control server that controls call processing between a plurality of servers, and a standby call control server that operates by switching to the active system when a failure occurs in the active call control server Call control system,
With respect to the first call processing data used for the call processing being executed by the current server and the call processing executed by the own server, the active call control server performs each partial processing in the order of occurrence of the partial processing constituting the call processing. Storing first event management table information in which bibliographic information including information to be specified is registered;
The active call control server updates the first event management table information stored in the bibliographic information related to the generated partial process when the partial process constituting the call process is generated based on the signal received from the outside. If it is determined based on the updated bibliographic information that the first event management table information needs to be synchronized with the standby call control server, the update of the first event management table information is stored in the standby Generating a transfer request for transfer to the system call control server;
The active call control server transferring the update of the first event management table information to the standby call control server based on the generated transfer request;
Each of the partial processing in the order of occurrence of the partial processing constituting the call processing, with respect to the second call processing data used for the call processing being executed on the own server and the call processing executed on the own server, by the standby call control server Storing second event management table information in which bibliographic information is registered;
The standby call control server updates the stored second event management table information with the transferred information when the updated portion of the first event management table information is transferred from the active call control server. And steps to
The active call control server performs partial processing generated based on the signal received from the outside using the first call processing data;
The active call control server monitoring the first event management table information at predetermined time intervals and identifying a partial process to be executed based on the stored bibliographic information;
The active call control server executing the specified partial processing using first call processing data stored in the first data storage unit;
The standby call control server monitoring the second event management table information at a predetermined time interval and identifying a partial process to be executed based on the stored bibliographic information;
Requesting the active call control server for new call processing data required when the standby call control server executes the partial process specified by monitoring the second event management table information;
When new call processing data is requested from the standby call control server, the active call control server acquires the corresponding first call processing data and transfers it to the standby call control server And responding with
The standby call control server updates the stored second call processing data with the first call processing data transferred in response to requesting the new call processing data; Performing a synchronization process with the information stored in the active call control server;
The standby call control server includes a step of executing a partial process excluding a signal transmission process to an external server among the specified partial processes to be executed using the second call processing data. A redundant method of information used for call control.

Images