JP2007174047A - Call control method and call control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a call control method and a call control system capable of reducing throughput at a called party. <P>SOLUTION: As seen an edge node (2) and a call agent CA (node) (3) of a VoIP system, the call control system is applied to a system in which a subscriber holding device is separated from a device for performing call control. When processing concentrates on a particular node (3-2), processing is executed in proxy by other node (calling node (3-1)) having a margin in processing. In addition, processing such as lowering of sound quality and postponing of provision for a part of services is performed during proxy execution. Consequently, priority is given to transmission of a call even if service quality is deteriorated in order to perform efficient connection processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a call control method and a call control system for reducing the processing amount on the called side.

  Conventional telephone exchanges accommodate subscribers in each area and use the CPU installed in the exchange containing the subscribers to connect the call. When incoming calls were concentrated or the number of outgoing calls increased, the switch was overloaded.

  In addition, in a telephone service (hereinafter referred to as VoIP) system using an IP network, a device (hereinafter referred to as an edge node) that accommodates subscribers in the IP network and a call agent CA (hereinafter referred to as a device that controls a call). Since the node is separated, the subscriber controlled by the node is independent of the subscriber accommodated by the edge node (see, for example, Non-Patent Document 1), but the arrangement of subscriber data and the control of the edge node In many cases, a node that performs connection processing for a certain subscriber is fixed because of the relation. For this reason, even if unexpected traffic is added due to the occurrence of a disaster or the like, it is difficult to immediately load balance between nodes.

For this reason, in the conventional technology, for example, in the event of a disaster such as an earthquake, immediately after the earthquake, a telephone call for confirmation of safety from the outside of the prefecture to residents in the disaster area is inundated, and a specific switch or node is called. As a result of the concentration of communication, communication devices in the earthquake disaster region may become congested, resulting in a congestion state in which the communication rate is significantly reduced. In addition, if the congestion is left as it is, it is difficult to make a call from outside the prefecture, so redialing may increase and further congestion may occur.
RFC 2543 “SIP: Session Initiation Protocol” (1999 IETF) 1.4.2 Locating a SIP Server and 1.4.5 Locating a User

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a call control method and a call control system for reducing the processing amount on the called side.

  The present invention has been made to solve the above-described problems, and the invention according to claim 1 is a database that holds information related to call processing of a plurality of terminals, and call control that controls calls of the terminals. In a call control method used in a call control system in which a device and a housing device that houses the terminal are connected to each other via a network, the plurality of call control devices identify a call control device that has caused congestion Whether or not the call control device information is held, and when the call is transmitted to the callee terminal, the held call control device information includes the callee call control device in which the callee terminal is accommodated. And if the called call control device is included in the held call control device information, the call processing of the called terminal is accessed by accessing the called database containing the called terminal. Information about Acquired, on the basis of the acquired information, to perform a call control to the called terminal, a call control method according to claim.

  According to a second aspect of the present invention, in the call control method according to the first aspect, when the call control device is included in the call control device information held by the callee side call control device, the call control device receives the call control device. Access to the called party database that accommodates the calling terminal, obtain information on the call processing of the called terminal, determine whether or not to provide the additional service, and if the availability determination is not, the requested additional service If yes, call control to the called terminal is performed based on the acquired information.

  According to a third aspect of the present invention, in the call control method according to any one of the first to second aspects, the call control device includes information specifying the call control device and the call control device information. In comparison, if the information specifying the call control device is included in the call control device information, the access restriction of the accommodating device that is processing the terminal call in relation to the call control device is released. It is characterized by performing.

  According to a fourth aspect of the present invention, in the call control method according to any one of the first to second aspects, the call control device includes information specifying its own call control device and the call control device information. In comparison, if the information specifying the call control device is included in the call control device information, the access processing of the accommodating device that is processing the call of the terminal in association with the call control device itself When the call is transmitted to the callee terminal so that the call can be controlled from other call control apparatuses, the held call controller information includes the callee call control apparatus in which the callee terminal is accommodated. And if the called side call control device is included in the held call control device information, the called side terminal is accessed to access the called side database. Information on the call processing of Provide access control with Waru containment device, to perform a call control to the called terminal, wherein

  According to a fifth aspect of the present invention, in the call control method according to any one of the first to fourth aspects, the call control system further includes a network management unit, and the network management unit includes a plurality of calls. Monitoring a congestion state or failure state of the control device, or receiving a signal indicating a congestion or failure state from the call control device, determining congestion or failure of the call control device, and any one of the call control devices When congestion or failure occurs, the call control device is notified as call control device information designating the call control device that has caused congestion, and the call control device further transmits the notified call control device information. It is characterized by holding.

  According to a sixth aspect of the present invention, in the call control method according to any one of the first to fifth aspects, the call control device includes the call control device information held by the called call control device. If included, select a third call control device other than its own call control device and the called call control device in which the called terminal is accommodated, and transfer the call to the third call control device It is characterized by doing.

  According to a seventh aspect of the present invention, there is provided a database that holds information related to call processing of a plurality of terminals, a call control device that controls calls of the terminals, and a storage device that stores the terminals via a network. In a call control system connected to each other, when the plurality of call control devices transmit a call to a callee terminal, a means for holding call control device information for identifying a call control device that has caused congestion, Means for determining whether the held call control device information includes a called call control device in which the called terminal is accommodated, and the call control device information held by the called call control device If included, means for accessing a called party database that accommodates the called terminal and acquiring information relating to call processing of the called terminal, and based on the acquired information, the called terminal Call control to And stage, characterized by comprising.

  According to the present invention, when the callee side becomes congested, the processing of the callee node is delegated by another node (calling node), and the load on the callee node is alleviated. It is possible to improve the communication rate on the called side during congestion.

  According to the second aspect of the present invention, when the called side becomes congested, complicated processing can be reduced by refusing the requested additional service to the called side, so that the called side can receive the call at the time of congestion. The caller's communication rate can be improved. Further, it is possible to reduce complicated processing in the calling side node and the called side node.

  According to the invention of claim 3, even when access control is performed between the called side node and the called side edge node, if the called side becomes congested, the called side node By canceling the access control and not performing the access control on the called side, it is possible to improve the communication rate of the called side when the called side is congested. In addition, when the callee node releases the access control of the callee edge node, appropriate call control can be performed.

  According to the invention of claim 4, even when access control is performed between the called side node and the called side edge node, if the called side becomes congested, the called side node Allows the callee node to perform access control for the callee edge node, and the callee node performs access control with the callee edge node to Even when there is access control, the communication rate of the called side can be improved when the called side is congested. In addition, the caller node can perform appropriate call control by acting as the access control of the callee edge node.

  According to the invention of claim 5, the congestion or failure of a specific node is notified to each node by the network management means, and each node holds information on the specific node that is congested or failed, so that the callee can It is possible to improve the communication rate on the called side during congestion.

  According to the invention of claim 6, when the called side becomes congested, the call control device and the third call control device other than the called side call control device in which the called side terminal is accommodated are called. By transferring, it is possible to improve the communication rate of the called side when the called side is congested.

  According to the invention of claim 7, when the called side becomes congested, processing of the called side node is performed by another node (calling node), and the load on the called side node is reduced. Therefore, the communication rate of the called side when the called side is congested can be improved.

First, an outline of the embodiment will be described.
For example, in the case of VoIP, the user dials a telephone number as an operation for making a call. In VoIP, a dialed telephone number needs to be recognized by an IP address, and conversion from a telephone number to an IP address is necessary.
In a large-scale network, a database is used for this conversion, and a call is made to the destination IP address as VoIP by making an inquiry to the corresponding database based on the telephone number.
As described above, a call path is established (using a node and a subscriber database), and then a call is performed between the node and an edge node (call control device).
As for call control, even for SIP, H.264 is used. This is basically the same for both H.323 and MGCP.

In such a VoIP, for example, when a disaster occurs, call concentration to a node that processes subscribers in the affected area occurs, and the node exceeds the processing capacity. As a result, even if there is room in the subscriber database, it becomes difficult for the node exceeding the processing capacity to access the subscriber database, and the node and the terminal accommodated in the subscriber database associated with the node Communication of the call to the subscriber becomes impossible. In order to solve such a state, it is necessary for another node to execute processing of a node on which processing is concentrated.
Therefore, the present embodiment is applied to a system in which a subscriber accommodation device and a device that performs call control are separated as seen in the edge node and the node of the VoIP system, and when processing is concentrated on a specific node, The processing is performed on behalf of another node (calling side node) that has a margin for processing.
Further, during the processing, processing such as lowering the voice quality and canceling provision of some services is performed, and even if the service quality is lowered, priority is given to call communication and efficient connection processing is executed.

Embodiments of the present invention will be described below with reference to the drawings. Components shown by the same numbers in FIGS. 1 to 9 all indicate the same components.
FIG. 1 is a block diagram showing a configuration of a call control system to which a call control method according to a first embodiment of the present invention is applied.
FIG. 1 shows a normal system state in which the load is not concentrated on a specific node. In this figure, reference numeral 1 denotes a terminal accommodated in the node 3 that performs call control. Control relating to the calling terminal 1-1 is originating side control 4-1 of the originating node 3-1, and control relating to the destination terminal 1-2 is This is implemented by the destination side control 4-2 of the destination node. Subscriber contract information and the like necessary for performing call control are held in the subscriber data 5, and the calling side control 4-1 uses the subscriber data 5-1 of the calling terminal and the called side control 4-2. Refers to the subscriber data 5-2 of the called terminal. Further, the edge node 2, the originating node 3, and the subscriber data 5 communicate via the network 9.

Each node 3 in the first embodiment monitors its congestion state by NW management means. The NW management unit acquires information including the congestion state of the node by notification from the node, or acquires information including the congestion state of the node by polling the node by the NW management unit. Also, the NW management means automatically determines congestion based on the acquired information. Alternatively, the NW management unit presents the acquired information regarding the congestion of the node to a person (maintenance person) who manages the network, and provides an input unit for determining and inputting the congestion state based on the judgment of the maintenance person.
This NW management means may be included in a call control means on the called side, a call control means on the calling side, or a third call control means other than the calling side and the called side. Further, other means not particularly specified in the embodiments and the drawings may be used. Moreover, you may perform by the input means by judgment of a maintenance person. Therefore, the NW management means is not particularly shown in the figure.

  FIG. 2 shows a system state when the load is concentrated on the destination node 3-2 and the destination node 3-2 is congested in the embodiment of FIG. At this time, the destination side control 4-2 is executed by the calling node 3-1, and the calling node 3-1 refers to the subscriber data 5-2 of the called terminal. The operation will be described in detail below.

  FIG. 3 is a flowchart for explaining the flow of operations of the first embodiment. First, when the destination node 3-2 falls into a congestion state (step S01), the NW management unit sets the address 8 of the congestion node 3-2 to each node in the network (step S02). Next, when the calling node 3-1 receives a call from the subscriber's terminal 1-1, the calling node 3-1 acquires the address of the called node based on the address of the called terminal 1-2. Compared with the address 8 set in S02 (step S03), if they do not match, normal connection processing is performed (step S04, step S05). On the other hand, if they match, the originating node 3-1 activates the terminating side control 4-2, and the terminating side control 4-2 accesses the subscriber data 5-2 of the terminating terminal (step S06). The call arrives at the destination terminal 1-2 (step S07).

In the above description, when the calling node 3-1 receives a call from the subscriber terminal 1-1, the calling node 3-1 acquires the address of the called node based on the address of the called terminal 1-2. However, for example, when the calling node 3-1 receives a call from the terminal 1-1 of the subscriber, the calling node 3-1 accesses the address conversion server based on the address of the called terminal 1-2, and performs address conversion. The address of the destination node may be acquired from the server.
Further, each node is provided with a rule for uniquely determining the address of the incoming node from the address of the destination terminal 1-2, and these are executed at each node.
These are processes normally performed in SIP or the like. As a method of examining the destination node 3-2 based on the address of the destination terminal 1-2 from the source node 3-1, all other conventional techniques may be used.

Next, a second embodiment will be described. The system configuration of this embodiment is the same as that shown in FIGS.
FIG. 4 is a flowchart for explaining the operation of the second embodiment. Here, the procedure up to step S06 is performed in the same manner as in FIG. 3 of the first embodiment. Then, following step S06, it is determined whether or not there is a request for additional services (step S11). Here, the supplementary service is, for example, a service such as one-to-many communication such as multi-party call, instead of one-to-one communication represented by basic connection for call waiting and telephone service.
If the additional service is requested in step S11, the requested additional service is rejected, for example, the corresponding call is disconnected (step S12), and if it is a basic connection, the incoming call is received at the destination terminal 1-2 (step S11). S07). The determination as to whether the additional service is requested in step S11 is performed based on, for example, information stored in the subscriber data 5-2 of the accessed called terminal. With the above procedure, when the originating node 3-1 acts as a proxy for the congestion node 3-2, the load on the originating node 3-1 can be suppressed and the connection process can be simplified.

In this embodiment, the subscriber data 5 includes information related to the additional service related to the subscriber terminal, but the subscriber data 5 includes, for example, a call state such as during a call as information for realizing the additional service. Information etc. may be included.
As for the above-mentioned additional service, if the calling node 3-1 matches in the comparison in step S03, the requested additional service may be rejected.

In addition, as a service restriction in the second embodiment, the call is disconnected based on the presence or absence of the additional service, but in addition to the additional service, the communication bandwidth, the priority of the data communication, the voice quality, etc. It may be lowered.
Also, for example, it is possible not to provide a service that cannot be performed by the corresponding node due to resource reasons, or to simply provide a service other than the basic service.

Next, an embodiment when there is access control will be described. Access control refers to, for example, whether or not a call route from a caller to a callee can be established, and performs bidirectional data communication filtering for conversation after the route is established. is there. In other words, a conversation cannot be made unless access control is normally performed on both the calling side and the called side.
If there is such access control on the called side and there is congestion on the called side, there is a possibility that the call cannot be communicated to the called side due to the load on the called side's access control. There is. In the following third and fourth embodiments, a description will be given of a method that enables communication to the called side even when there is access control on the called side.

FIG. 5 is a block diagram showing a configuration of a call control method and a call control system for mitigating the processing amount on the callee side at the normal time when there is access control according to the third and fourth embodiments.
FIG. 5 shows a normal system state in which the load is not concentrated on a specific node. In addition to the system configuration of FIG. 1, the edge node 2 has an access control 6 function. This access control is a function such as restricting the terminal 1 from accessing various devices in the network. For example, even though the calling terminal 1-1 can access the node 3-1, the node 3-2 It has a function of filtering so that it cannot be accessed. The access control 6 operates according to an instruction from the edge node control 7 of the node 3 corresponding to the host device that controls the edge node 2.

FIG. 6 is a block diagram showing the configuration of a call control method and a call control system for mitigating the processing amount on the called side that does not control the edge node during congestion when there is access control according to the third embodiment. .
FIG. 6 shows a system state when the load is concentrated on a specific node and the destination node 3-2 in FIG. 5 is congested. In FIG. 6, the point that the destination side control 4-2 is executed by the calling node 3-1 is the same as that of the first embodiment, but the access control 6-2 is canceled and the destination side control 4 is canceled. -2 is different in that edge node control is not performed.

  The operation of the third embodiment of FIGS. 5 and 6 will be described using the flowchart of FIG. First, when the destination node 3-2 falls into a congestion state (step S01), the NW management unit sets the address 8 of the congestion node 3-2 to each node in the network (step S02). The congestion node 3-2 invalidates the access control unit 6-2 of the edge node 2-2 (step S21). As a result, the destination terminal 1-2 can exchange a message directly with the originating node 3-1. Next, when receiving a call from the terminal 1-1 of the subscriber controlled by the calling node 3-1, the calling node 3-1 acquires the address of the called node based on the address of the called terminal 1-2. Compared with the address 8 set in step S02 (step S03), if they do not match, normal connection processing is performed (step S04, step S22, step S05). On the other hand, if they match, the calling side control 4-2 is activated at the calling node 3-1, and the subscriber data 5-2 of the called terminal is accessed (step S06). Then, the incoming side control 4-2 skips the access control of the edge node 2-2 (step S23) and arrives at the controlled incoming terminal 1-2 (step S07).

FIG. 8 is a block diagram showing the configuration of a call control method and a call control system for mitigating the amount of processing on the called side that controls an edge node during congestion when there is access control according to the fourth embodiment of the present invention. FIG.
FIG. 8 shows a system state when the load is concentrated on a specific node and the destination node 3-2 of FIG. 5 is congested. At this time, the arrival side control 4-2 is executed by the originating node 3-1, which is the same as that of the first embodiment, but the edge node control 7 relating to the access control 6-2 at the originating node 3-1. -2 is different.

  Next, the flow of operation of the fourth embodiment will be described with reference to the drawings. FIG. 9 is a flowchart used in the fourth embodiment of FIGS. 5 and 8. First, when the destination node 3-2 falls into a congestion state (step S01), the NW management unit sets the address 8 of the congestion node 3-2 to each node in the network (step S02). The congestion node 3-2 allows the edge node 2-2 to perform control of the access control unit 6-2 from the originating node (step S31). Next, when receiving a call from the terminal 1-1 of the subscriber controlled by the calling node 3-1, the calling node 3-1 acquires the address of the called node based on the address of the called terminal 1-2. Compared with the address 8 set in step S02 (step S03), if they do not match, normal connection processing is performed (step S04, step S32, step S05). On the other hand, if they match, the calling side control 4-2 is activated at the calling node 3-1, and the subscriber data 5-2 of the called terminal is accessed (step S06). Further, the access control 6-2 of the edge node 2-2 is performed by the edge node control 7-2 (step S33), and the incoming call arrives at the control terminal 1-2 (step S07).

In the description of the fourth embodiment in FIG. 9, the description has been made on the assumption that the access control 6-2 in the edge node 2-2 exists in advance. However, it is also possible to perform access control on the calling side as needed without determining that there is access control in advance.
For example, information indicating that the edge node 2-2 has access control 6-2 is stored in the subscriber terminal subscriber data 5-2, and whether access control is necessary or not based on this information is stored. It is possible to make the determination and perform the same processing as described above if necessary.
For example, in the flowchart of FIG. 9, the steps up to step S06 are the same, and the subscriber terminal subscriber data 5-2 is accessed (step S06), and then, for example, from the accessed subscriber terminal subscriber data 5-2. Based on the information, it is determined whether or not the access control 6-2 of the edge node 2-2 is necessary. When access control is necessary, the edge node control 2-2 performs access control 6-2 on the edge node 2-2 (step S33), and arrives at the control destination terminal 1-2 (step S07). If access control is not required, the call arrives at the control terminal 1-2 as it is (step S07).

In the present embodiment, as a control performed on the calling side, when receiving a call from the terminal 1-1 of the subscriber controlled by the calling node 3-1, the calling node 3-1 is called the called terminal 1-2. An example is shown in which the address of the destination node is obtained based on the address of, and then compared with address 8.
In this way, the calling party not only directly acquires the information of the called node from the called address, but also indirectly acquires the information of the roaming destination node from the called address via the home network. In particular, the present invention can be applied to a mode of acquiring node information.

In addition, as the present embodiment, at the time of congestion on the called side, communication on the called side is improved by reducing the load on the called side by acting on the called side on the calling side. It is also possible to perform the processing on the called side on behalf of the third node other than the called side and the calling side.
For example, a lightly loaded node may be selected as the third node, or a round robin method may be selected from several candidates.

  Further, in the present embodiment, the explanation has been made on the time when the destination node is congested. However, the method according to the present invention can be applied to the case where the destination node fails. In this case as well, a node failure is determined by the NW management means in the same manner as node congestion.

  In addition, although VoIP is shown as an example of adaptation of the present invention, the present invention can be applied to any system such as VoIP in which a subscriber accommodation device and a device that performs call control are separated. For example, a mobile phone or an IP mobile phone can be applied with the above configuration.

  Further, as an adaptation of the present invention, the congestion on the called side at the time of disaster has been a problem. However, the present invention can be applied not only at the time of disaster but also at the time of congestion that normally occurs.

  Further, as embodiments of the invention, the description has been made using the first to fourth embodiments, but each of the functions described in the first to fourth may be used independently, Further, they may be used in combination with each other.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes a design and the like within a scope not departing from the gist of the present invention. It is.

  The present invention is most suitable for use in a call control system in which a device for accommodating subscribers such as a VoIP system and a device for performing call control are separated.

It is a block diagram which shows the structure of the call control system by 1st and 2nd embodiment of this invention. It is a block diagram which shows the system state at the time of congestion of the call control system in 1st embodiment of this invention. It is a figure which shows the flowchart for demonstrating the operation | movement of said 1st embodiment. It is a figure which shows the flowchart for demonstrating the operation | movement of 2nd embodiment of this invention. It is a block diagram which shows the structure of the call control system by 3rd and 4th embodiment of this invention. It is a block diagram which shows the system state at the time of congestion of the call control system by 3rd embodiment of this invention. It is a figure which shows the flowchart for demonstrating operation | movement of 3rd embodiment of this invention. It is a block diagram which shows the system state at the time of congestion of the call control system by 4th Embodiment of this invention. It is a figure which shows the flowchart for demonstrating operation | movement of 4th Embodiment of this invention.

Explanation of symbols

1 Originating and terminating terminals 2 Originating and terminating edge nodes 3 Originating and terminating nodes 4 Originating and terminating control 5 Originating and terminating subscriber data 6 Originating and terminating side data Access control 7 Originating and terminating edge node control 8 Congested node address 9 Network

Claims (7)

Used in a call control system in which a database that holds information regarding call processing of a plurality of terminals, a call control device that controls calls of the terminals, and a storage device that stores the terminals are connected to each other via a network In a call control method,
When the plurality of call control devices hold call control device information for identifying a call control device that has caused congestion, and when a call is transmitted to a called terminal, the received call control device information is included in the held call control device information. It is determined whether or not a called-side call control device in which the called-side terminal is accommodated, and when the called-side call control device is included in the held call control device information, the called-side terminal To obtain information related to the call processing of the called terminal, and to perform call control to the called terminal based on the obtained information;
A call control method characterized by the above. The call control device accesses a callee database containing the callee terminal when the callee call control device includes the held call control device information and calls the callee terminal. Obtains information on processing, determines whether or not to provide an additional service, rejects the requested additional service if the determination is not possible, and determines that the incoming call is based on the acquired information if the determination is yes Perform call control to the terminal
The call control method according to claim 1. The call control device compares information specifying the call control device with the call control device information, and if the information specifying the call control device is included in the call control device information, the call control device Canceling the access restriction of the accommodating device that is handling the terminal call in connection with the control device;
The call control method according to claim 1, wherein: The call control device compares information specifying the call control device with the call control device information, and if the information specifying the call control device is included in the call control device information, the call control device The access processing of the accommodation device that is processing the call of the terminal in relation to the control device can be controlled from a call control device other than itself, and the above-mentioned holding is performed when the call is transmitted to the called terminal. It is determined whether or not the call control device information includes a callee call control device in which the callee terminal is accommodated, and the call control device information is included in the held call control device information. Access to the called party database that accommodates the called terminal, obtain information on call processing of the called terminal, perform access control with the accommodating device related to the called terminal, and Perform call control to the terminal
The call control method according to claim 1, wherein: The call control system further includes network management means,
The network management means monitors a congestion state or failure state of a plurality of call control devices, or receives a signal indicating a congestion or failure state from the call control device, and determines congestion or failure of the call control device When any of the call control devices is congested or failed, the call control device is notified as call control device information for identifying the call control device that has caused the congestion or failure.
The call control method according to any one of claims 1 to 4, wherein the call control device further holds the notified call control device information. The call control device, other than the call control device in which the call control device and the callee terminal are accommodated when the call control device information is included in the held call control device information. Selecting a third call control device and transferring the call to the third call control device;
The call control method according to any one of claims 1 to 5, wherein: In a call control system in which a database that holds information related to call processing of a plurality of terminals, a call control device that controls a call of the terminal, and a storage device that stores the terminal are connected to each other via a network.
The plurality of call control devices hold means for holding call control device information for identifying a call control device that has caused congestion, and when the call is transmitted to the called terminal, the received call control device information is stored in the held call control device information. Means for determining whether or not a called-side call control device in which the called-side terminal is accommodated is included; and when the called-side call control device is included in the held call control device information, Means for accessing a callee database containing the caller terminal and acquiring information relating to call processing of the callee terminal; and means for performing call control to the callee terminal based on the acquired information ,
A call control system comprising:

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