JP6034816B2 - Traffic control device, traffic control method, and traffic control program - Google Patents

Description

  The present invention relates to a congestion control technique in a C-plane (control plane) for providing a communication service via a network.

  As a conventional congestion control technique, Patent Document 1 discloses a method for controlling outgoing calls that are directed to an exchange or a region that is difficult to communicate due to concentration of incoming calls in the public telephone network. Disclosed is a technology for regulatory encounters that does not connect the number of outgoing calls exceeding the value (control amount) allocated by each switch after the total number of calls (total control amount) communicated to each switch is allocated to each switch. Yes.

  In Patent Document 2 and Patent Document 3, in an IP telephone system for performing telephone communication via an IP (Internet Protocol) network, the function of the C-plane soft switch may be stopped due to the concentration of many calls. When congestion occurs, the number of calls is monitored as a detection method, and if it exceeds the predetermined number of calls, it is determined that the congestion is present, and call connection per unit time is permitted as the control method. A technique for controlling the number of call connections based on a call density that is a number is disclosed. In addition, a technique for controlling an INVITE signal in SIP (Session Initiation Protocol) based on call density is also disclosed.

  Further, in Patent Document 4, the exchange that has detected congestion reports the restriction information to the originating exchange by a method such as synergizing the restriction information with a response signal such as a common line signal system and a backward signal such as a disconnection signal. After the originating switch starts regulation control according to this regulation information instruction, the congestion switch changes the regulation amount depending on the congestion state, or the originating switch changes the regulation amount based on information obtained from the originating switch As described above, a technique is disclosed in which the regulation control is automatically performed by the feedback control of both the originating and terminating exchanges.

  Further, Patent Document 5 discloses a traffic for measuring a traffic amount between grounds in a relay network, and when a ground whose measurement result does not satisfy a required connection quality target is detected, a traffic for determining a source communication device related to the ground is determined. A control method technique is disclosed.

  On the other hand, a communication network (for example, refer to Patent Document 6) in which resources of a soft switch that performs session control are dynamically managed is becoming popular due to recent advances in virtualization technology.

  In a new communication network in which the resources of the soft switch that performs session control are dynamically managed, there is no logical bottleneck location. In addition, since the amount of logical resources used for session control in a communication network changes in real time, the conventional control total amount calculation method in congestion control cannot be applied. On the other hand, even in such a new communication network, “maximum use of network resources”, which is the basic concept of congestion control, is assumed to be an invariant requirement, and it is required to maximize the call communication rate. It is done.

  However, in a new communication network in which the resource amount of the soft switch dynamically changes according to the load, the conventional technology that detects the occurrence of congestion in units of soft switches may not be able to appropriately determine the congestion occurrence timing. . In view of such circumstances, Non-Patent Document 1 discloses a method for determining an appropriate control total amount following a change in available resource amount.

Japanese Patent Laid-Open No. 3-96050 JP 2004-88666 A JP 2004-304646 A JP-A-5-22407 Japanese Patent Application Laid-Open No. 5-167664 JP 2012-242994 A

Kensuke Takahashi and three others, “A Study on Total Control Calculation Method for Dynamic Resource Managed NW”, IEICE, 2013 IEICE Communication Society, Proceedings of Communication Society 2, September 2013 , P. 399

  In the invention described in Non-Patent Document 1, when allocating the determined total control amount, it is considered to distribute the total control amount to each session control device according to the ratio of the number of outgoing calls. However, in this method, since the call is distributed to all the session control devices, and each session control device makes a connection request to the subscriber terminal in the congested congestion area and other connection requests, it is based on the information of the previous period. Even if the total control amount is allocated, there is a high possibility that the traffic amount to each session control device will change, and the total control amount cannot be allocated appropriately, and the maximum use of network resources may not be possible. There is.

  The present invention has been made in view of the above circumstances, and appropriately determines the timing of occurrence of congestion in a communication network in which the resource amount of the soft switch dynamically changes according to the load, and the resources that can be used. An object of the present invention is to provide a traffic control device, a traffic control method, and a traffic control program capable of determining an appropriate control total amount following a change in the amount, and further appropriately allocating the determined control total amount. .

  In order to achieve the above-described object, the present invention provides a plurality of computers, which are resources necessary for providing various communication services to a terminal connected to a communication network, and each of the plurality of computers. By operating as either a session control device that accepts connection requests from terminals and performs connection processing between terminals, or a non-session control device that performs processing other than connection processing between terminals, or by waiting in a resource pool A resource management device for allocating resources according to service load fluctuations, and accepting a connection request to a terminal in the specific area to the session control apparatus when congestion occurs in the specific area of the communication network The traffic of a communication control system comprising a traffic control device for transmitting an instruction to limit the number Resource information including the number of operating session control devices and the number of non-session control devices is acquired from the resource management device, and resources of the resource pool are insufficient. A resource information acquisition unit that starts congestion control processing when it is detected, and a traffic information acquisition unit for each ground that acquires traffic information for each ground including information on the number of outgoing calls and the number of incoming calls for each incoming region of the session control device And a congestion area in which the number of outgoing calls by the latest incoming area exceeds a predetermined standard from the traffic information by ground, and using the acquired resource information and the acquired traffic information by land The control total amount that is the upper limit of the total number of requests for connection to the terminal in the congested area is determined, and the determined control total amount is in operation A total control amount determination unit that determines a call restriction value that is an upper limit of the number of connection requests accepted distributed to the session control device, and call restriction instruction information that includes the determined call restriction value, the session control A control instruction unit that transmits to the device, and the control total amount determination unit only sends a connection request to the terminal in the congestion area based on the resources allocated to the session control device in operation and the control total amount. The session control device to be performed is determined, and the total control amount is distributed to the determined session control device.

  In this way, when congestion occurs in a communication network operated by a communication control system in which computer resources are dynamically allocated according to the load, the maximum total control amount can be secured according to the resource usage status. The number of incoming calls to the congested area can be maximized. In addition, resources can be dynamically managed and distributed in congestion control, and session control devices that perform congestion control can be aggregated, so that network resources can be suitably used.

  Further, according to the present invention, in the traffic control device, when the congestion control process is started, the resource information acquisition unit acquires the latest resource information every predetermined time, and the traffic information acquisition unit classified by ground Acquires the latest traffic information by ground, and the control total amount determination unit can perform the maximum processing per device in the number of the session control devices in operation included in the acquired latest resource information. A value obtained by subtracting the total number of outgoing / incoming calls between terminals other than the congestion area obtained from the most recent traffic information by ground obtained from the value obtained by multiplying the number of calls is determined as the total control amount.

  By doing so, the maximum resources that can be used for processing connection requests addressed to terminals in the congested area are allocated, so that the number of incoming calls to the congested area can be maximized.

  In the traffic control device according to the present invention, the resource information acquisition unit stores the acquired resource information in a storage unit, and at the start of the congestion control process, the total control amount determination unit acquires the acquired The most recent incoming call count to the congested area obtained from the traffic information by ground is determined as the total control amount, and the value is stored in the storage means. Thereafter, the resource information acquisition unit The total control amount determination unit acquires the number of the session control devices in operation included in the acquired most recent resource information and the previous session stored in the storage unit. From the number of control devices, calculate the resource increase / decrease rate indicating the rate of increase / decrease of the resource allocation rate allocated to the session control device, The value of the resource change ratio that issued the previous value multiplied by the value of the control amount that has been stored in the storage means, and shall be determined as the control amount of time.

  By doing this, the initial total control amount for the congested area is set to the number of incoming calls destined for the area immediately before the congestion occurs, and thereafter, it is proportional to the increase / decrease of the resource allocation rate due to the tracking control to the actual traffic fluctuation. Change the total control amount to Therefore, it is possible to perform control conforming to changes in the resource state with high followability to actual traffic fluctuations.

  In the traffic control device according to the present invention, when the resource information acquisition unit determines that the resource information cannot be acquired from the resource management device, the ground-specific traffic information acquisition unit The information is acquired, and the control total amount determination unit detects the occurrence of congestion by specifying a congestion area where the number of outgoing calls for each incoming area exceeds a predetermined standard from the traffic information for each ground. Congestion monitoring processing is started, and when the occurrence of congestion is detected by the congestion monitoring processing, the total control amount determination unit controls the number of incoming calls to the congestion area most recently obtained from the ground-specific traffic information. The total amount was determined.

  In this way, even when resource control by the resource management device does not function properly, the traffic control device detects the occurrence of congestion and ensures the number of incoming calls to the congestion area immediately before the congestion occurs. Since the call restriction is activated, it is possible to realize congestion control utilizing the resources of the session control apparatus that is operating at that time.

The present invention also provides a plurality of computers, which are resources necessary for providing various communication services to a terminal connected to a communication network, and accepts connection requests from the terminal to each of the plurality of computers. Responding to changes in service load by operating as either a session control device that performs connection processing between terminals and a non-session control device that performs processing other than connection processing between terminals, or by waiting in a resource pool When the congestion occurs in a specific area of the communication network and the resource management apparatus that allocates resources, an instruction is sent to the session control apparatus to limit the number of connection requests received to terminals in the specific area. The traffic control device of the communication control system comprising the traffic control device In this method, resource information including the number of operating session control devices and the number of non-session control devices is acquired from the resource management device, and resources in the resource pool are insufficient. Sometimes starting congestion control processing, obtaining ground-specific traffic information including information summarizing the number of outgoing calls and the number of incoming calls for each incoming area of the session control device, and the latest traffic information for each ground The congestion area in which the number of outgoing calls for each incoming area exceeds a predetermined standard is specified, and the obtained resource information and the obtained traffic information for each ground are used to connect to the terminal in the identified congestion area Determine the total control amount that is the upper limit of the total number of requests received, and distribute the determined total control amount to the active session control devices Determining a call restriction value that is the upper limit of the number of connection requests accepted, and transmitting call restriction instruction information including the determined call restriction value to the session control device, When allocating the determined control total amount to the operating session control measures, the control total amount determining unit is configured to determine whether the congestion area is based on the resources allocated to the operating session control device and the control total amount. The session control device that performs only a connection request to the terminal is determined, and the total control amount is distributed to the determined session control device.

  In this way, when congestion occurs in a communication network operated by a communication control system in which computer resources are dynamically allocated according to the load, the maximum total control amount can be secured according to the resource usage status. The number of incoming calls to the congested area can be maximized. In addition, resources can be dynamically managed and distributed in congestion control, and session control devices that perform congestion control can be aggregated, so that network resources can be suitably used.

  The traffic control program of the present invention is for causing a computer to function as the traffic control device.

  In this way, the computer can function as the traffic control device.

  According to the present invention, in a communication network in which the amount of resources of a soft switch dynamically changes according to a load, it is possible to appropriately determine the timing of occurrence of congestion and to perform appropriate control following changes in the amount of available resources. It is possible to provide a traffic control device, a traffic control method, and a traffic control program capable of determining the total amount and further appropriately allocating the determined control total amount.

It is a figure which shows the structural example of the communication control system which concerns on embodiment of this invention. It is a figure which shows the structural example of each apparatus which comprises the communication control system which concerns on embodiment of this invention. It is a structure and data example of the resource information acquired from a resource management apparatus. It is a structure and data example of the traffic information classified by ground acquired from a traffic monitoring apparatus. It is an example of transition of resource information until congestion is detected by the resource management device. It is a flowchart which shows the process of the 1st control method for performing call control. It is a figure which shows the communication control system before call control. It is a figure which shows the communication control system after call control. It is a flowchart which shows the process of the 2nd control method for performing call control. It is an example of transition of the control total amount by the 2nd control method. It is a flowchart which shows the process of the 3rd control method for performing call control.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.

  FIG. 1 is a diagram illustrating a configuration example of a communication control system according to an embodiment of the present invention. As shown in FIG. 1, the IP network 8 includes a traffic control device 1, a resource management device 2, a traffic monitoring device 3, a resource pool 40, a session control device group 40S, a non-session control device group 40N, a load balancer 5, and a location. Server 6 is deployed.

  The resource management device 2 manages resources composed of a plurality of general-purpose computers 4 having a connection interface with the IP network 8, and uses each general-purpose computer 4 as a session control device 4S or as a non-session control device 4N. It is determined whether to use or reserve the resource pool 40 as a reserve resource. Further, the resource management device 2 notifies the traffic control device 1 of the occurrence of congestion when the spare resources of the resource pool 40 are insufficient (when the resource pool 40 is depleted or when a situation close to depletion occurs).

  Each general-purpose computer 4 may be used as the session control device 4S or the non-session control device 4N, and the resources of one general-purpose computer 4 are allocated to the session control device 4S and the non-session control device 4N. It is good also as what makes both coexist by. Further, the resource may be constituted by a plurality of types of general-purpose computers 4 having different processing performance.

  A connection request (for example, an SIP INVITE request) from the subscriber terminal 7 connected to the IP network 8 is transmitted to the load balancer 5, and the load balancer 5 accepts the connection request and sends the connection request to the session control device. Transfer to one of the session control devices 4S included in the group 40S. At this time, the load balancer 5 distributes connection requests so that the CPU (Central Processing Unit) utilization rates of all the session control devices 4S are leveled by using, for example, a round robin method or a hashing method.

  The session control device 4S that has received the connection request transferred from the load balancer 5 obtains the IP address of the destination subscriber terminal 7 from the location server 6, and the source subscriber terminal 7 and the destination subscriber terminal Establish a session with 7.

  A non-session service request (for example, a WEB site browsing request) from the subscriber terminal 7 is transmitted to the load balancer 5, and the load balancer 5 accepts the service request and sends the service request to the non-session control device. Transfer to one of the non-session control devices 4N included in the group 40N. At this time, the load balancer 5 distributes the service request so that the CPU usage rate of the non-session control device 4N is leveled by using, for example, a round robin method or a hashing method.

  The non-session control device 4N that has received the service request transferred from the load balancer 5 provides the requested non-session service to the requesting subscriber terminal 7.

  The traffic monitoring device 3 counts the number of connection requests (the number of outgoing calls) and the number of connections (the number of incoming calls) processed by each session control device 4S for each incoming region, so that the number of the latest outgoing calls and incoming calls , And the number of outgoing calls during the busiest hours is tabulated by the receiving area.

  In addition, when the traffic control device 1 deployed in the control center or the like is notified of the occurrence of congestion from the resource management device 2, the traffic control device 1 starts the congestion control processing and becomes the upper limit of the number of times of accepting a connection request to the congestion area. The total amount (the total number of connection requests accepted by all session control devices 4S) is calculated according to the resource usage status and traffic status at that time. Then, the traffic control device 1 includes, based on the total control amount, control instruction information (calling restriction instruction) that instructs each session control device 4S to include the call restriction value that is the upper limit of the number of connection requests accepted. Information) and the control instruction information is transmitted to each session control device 4S. The session control device 4S that has received this control instruction information performs call restriction (regulation encounter) so that the number of connections (number of incoming calls) addressed to the congested area is equal to or less than the designated call restriction value.

  Further, the traffic control device 1 controls each session when the number of outgoing calls addressed to the congested area is reduced during the call restriction, and the shortage of the resource pool 40 (the situation where the resource pool 40 is exhausted or near exhaustion) is resolved. Instruction information for canceling call restriction is transmitted to the device 4S. The session control device 4S that has received this instruction information cancels the call restriction for the congestion area.

  Next, the configuration of main devices constituting the communication control system of FIG. 1 will be described with reference to FIG. 2 (see FIG. 1 as appropriate). However, FIG. 2 describes only main functions of each device, and includes input means for data input, communication means for transmitting and receiving data via a network, output means for displaying messages, and the like. Description of storage means for storing various information is omitted.

  FIG. 2 is a diagram illustrating a configuration example of main apparatuses constituting the communication control system according to the embodiment of the present invention. As shown in FIG. 2, the traffic control device 1 includes a resource information acquisition unit 11, a ground-specific traffic information acquisition unit 12, a control total amount determination unit 13, and a control instruction unit 14. These are realized by a CPU (not shown) included in the traffic control device 1 executing a predetermined control program (traffic control program) stored in the storage unit.

  The resource information acquisition unit 11 acquires resource information (details will be described later with reference to FIG. 3) indicating the resource allocation status from the resource management device 2. Further, the resource information acquisition unit 11 starts the congestion control process when notified of the occurrence of congestion from the resource management apparatus 2 and starts the congestion monitoring process when communication with the resource management apparatus 2 is interrupted. Let The ground-specific traffic information acquisition unit 12 acquires traffic information for each incoming area from the traffic monitoring device 3 (hereinafter referred to as “traffic-specific traffic information”, details will be described later with reference to FIG. 4).

  For example, when the occurrence of congestion is notified from the resource management device 2, the total control amount determination unit 13 determines whether the entire session control device 4 </ b> S, that is, the session control device group 40 </ b> S can accept the congestion area according to a predetermined calculation method. Determine the total amount of control. A specific method for calculating the total control amount will be described later with reference to FIGS. Based on the total control amount determined by the total control amount determination unit 13, the control instruction unit 14 provides control instruction information (call restriction instruction information) for instructing call restriction to each session control device 4 </ b> S including the call restriction value. When the congestion is resolved, the call control cancellation instruction information is transmitted to each session control device 4S.

  The resource management device 2 includes a resource control unit 21, a resource monitoring unit 22, and a congestion detection unit 23. These are realized by a CPU (not shown) included in the resource management device 2 executing a predetermined control program stored in the storage unit.

  When the resources allocated to the session control device group 40S and the non-session control device group 40N are insufficient, the resource control unit 21 pays out the standby general-purpose computer 4 from the resource pool 40, and the session control device 4S or the non-control device. Operate as the session control device 4N. On the other hand, when the resources allocated to the session control device group 40S and the non-session control device group 40N are redundant, the resource control unit 21 is connected to the computer operating as the session control device 4S or the non-session control device 4N. Stop operation, pull them back to the resource pool 40 and wait. Further, the resource control unit 21 generates resource information indicating the resource allocation status (details will be described later with reference to FIG. 3) and transmits the resource information to the traffic control device 1.

  The resource monitoring unit 22 collects information on the CPU usage rate of each computer operating as the session control device 4S and the non-session control device 4N, thereby using the CPU usage of the session control device group 40S and the non-session control device group 40N. Calculate the rate. When the congestion detection unit 23 detects a shortage of resources in the resource pool 40 (depletion or occurrence of a situation close to depletion), the congestion detection unit 23 notifies the traffic control device 1 of the occurrence of congestion (see FIG. 5 for details). Will be used later).

  The traffic monitoring device 3 receives the number of connection requests (number of outgoing calls) and the number of connections (number of incoming calls) from each session control device 4S and generates traffic information (see FIG. 4) by location. Another traffic information totaling unit 31 is provided.

  Each session control device 4S constituting the session control device group 40S includes a connection request processing unit 41, an outgoing call restriction unit 42, a CPU utilization rate measurement unit 43, and an outgoing / incoming call number information collection unit 44. These are realized by a CPU (not shown) included in the session control device 4S executing a predetermined control program stored in the storage unit.

  The connection request processing unit 41 accepts a connection request from the caller subscriber terminal 7 (see FIG. 1) transferred from the load balancer 5 and the subscriber terminal 7 designated as the destination and the caller subscriber. Control to establish a session with the terminal 7 is performed. In addition, the connection request processing unit 41 limits the number of connection processes that are received from the subscriber terminal 7 in response to a connection request to the congestion area so as to satisfy the call restriction value notified from the call restriction unit 42.

  The call restriction unit 42 sends a call restriction value for restricting a connection request to the congestion area to the connection request processing unit 41 according to the control instruction information (call restriction instruction information) received from the traffic control device 1. Notice. The CPU usage rate measuring unit 43 measures the CPU usage rate (processing load) of the device itself, stores the measurement result in a storage unit (not shown), and stores the stored CPU usage according to a request from the resource management device 2. The rate is transmitted to the resource management device 2. The outgoing / incoming call number information collection unit 44 measures the number of connection requests (number of outgoing calls) and the number of connections (number of incoming calls) for each incoming area, stores the measurement results in storage means (not shown), and traffic. In accordance with a request from the monitoring device 3, the stored number of outgoing calls and the number of incoming calls for each incoming area are transmitted to the traffic monitoring device 3.

  FIG. 3 shows a configuration and data example of the resource information acquired from the resource management device 2. As shown in FIG. 3, the resource information 91 is abbreviated as the number of session control devices (hereinafter abbreviated as “SC number” as appropriate) and the CPU usage rate of the entire session control device (hereinafter as “SC usage rate” as appropriate). ), The number of non-session control devices (hereinafter abbreviated as “NSC number” as appropriate), the CPU utilization rate of the entire non-session control device (hereinafter abbreviated as “NSC utilization rate” as appropriate), and the number of pools. It is configured. In the data example of FIG. 3, a total of 10 general-purpose computers 4 having the same processing performance are deployed as resources, each of which operates as a session control device 4S and a non-session control device 4N, and the remaining 4 computers. Are pooled in the resource pool 40, and the CPU usage rate of the entire session control device 4S is 65% and the CPU usage rate of the entire non-session control device 4N is 75%. When resources are configured by a plurality of types of general-purpose computers 4 having different processing performances, these values are calculated using the number of devices converted by multiplying the weight according to the processing performance and the CPU usage rate. Shall be.

  FIG. 4 shows a configuration and data example of ground-specific traffic information acquired from the traffic monitoring device 3. As shown in FIG. 4, the traffic information 92 according to the ground is configured by repeating a data set including an incoming area, the number of outgoing calls, the number of incoming calls, and the number of outgoing outgoing calls as many times as the number of incoming areas. Yes. Here, the incoming area is an area that is set by a communication carrier as a unit for performing outgoing call control by ground. The number of outgoing calls is the latest number of calls per minute sent to subscribers in the area. The number of incoming calls is the number of calls actually received by connection processing. The number of calls sent during the busy hour is the number of calls per minute in the normal busy hour that was sent to subscribers in the area. In the data example of FIG. 4, the number of the latest outgoing calls addressed to the subscribers in the area A is 25 (calls / minute), the number of incoming calls is 24 (calls / minute), and the number of outgoing calls is 60 (calls / minute) ), The number of the latest outgoing calls addressed to subscribers in region B is 40 (calls / minute), the number of incoming calls is 38 (calls / minute), and the number of outgoing calls is 95 (calls / minute). Represents that.

  Next, an operation example when congestion occurs in the communication control system shown in FIG. 1 will be described with reference to FIGS. Here, in order to simplify the explanation of the operation, a total of 10 general-purpose computers 4 having the same processing performance are deployed as resources, and in the initial state, three of them are respectively a session control device 4S and a non-session. It is assumed that it is operating as the control device 4N. Further, it is assumed that the resource management device 2 detects the occurrence of congestion due to a shortage of resources immediately before paying out the last general-purpose computer 4 remaining in the resource pool 40.

  FIG. 5 is an example showing transition of the resource information 91 from the initial state at time T1 until the resource management device 2 detects congestion at time T7. It is assumed that the threshold of the CPU utilization rate for the resource management device 2 to additionally operate the session control device 4S or the non-session control device 4N is 90%. Therefore, the resource management device 2 determines that additional operation of the device is necessary for each numerical value surrounded by a thick frame in FIG.

  At time T1, initial normal operation is performed, the number of SCs (number of session control devices) is 3, the SC usage rate (CPU usage rate of the entire session control device) is 65%, and the number of NSCs (non-session control device) 3), the NSC usage rate (CPU usage rate of the entire non-session control device) is 75%, and the number of pools is 4.

  At time T2, since the SC utilization rate has increased to 90% as the call volume increases, the resource management device 2 determines that an additional operation of the session control device (SC) 4S is necessary, and the general purpose from the resource pool 40 One computer 4 is paid out and operated as SC4S. Thereby, the number of SCs at the next time T3 is 4, and the number of pools is 3.

  At time T3, the NSC utilization rate has increased to 90% with an increase in non-session service load, so the resource management device 2 determines that additional operation of the non-session control device (NSC) 4N is necessary, One general-purpose computer 4 is paid out from the resource pool 40 and is operated as an NSC 4N. Thereby, the number of NSCs at the next time T4 is four, and the number of pools is two.

  At time T4, with the additional operation of NSC 4N, the NSC utilization rate decreases to 65%, and normal operation is performed with both the number of SCs and the number of NSCs of 4 and the number of pools of 2.

  At time T5, the SC usage rate has increased to 95% with a sudden increase in the amount of calls, so the resource management device 2 determines that an additional operation of SC4S is necessary. At this time, since the NSC utilization rate is as low as 60%, the resource management device 2 diverts one of the four units operating as the NSC 4N to operate as the SC 4S. As a result, the number of SCs at the next time T6 is 5, and the number of NSCs is 3.

  At time T6, the SC utilization rate is still high at 95% despite the fact that NSC4N was diverted and SC4S was additionally operated, so that the resource management device 2 needs to additionally operate SC4S. The general-purpose computer 4 is paid out from the resource pool 40 and operated as SC4S. As a result, the number of SCs at the next time T7 is 6, the number of NSCs is 3, and the number of pools is 1.

  At time T7, the SC utilization rate is still as high as 90% despite the SC4S being additionally operated, so the resource management device 2 determines that the SC4S additional operation is necessary. If the last one is paid out from the resource pool 40, the number of pools in the resource pool 40 becomes zero and the resources are depleted. Therefore, the resource management device 2 detects the occurrence of congestion at this time, and the traffic control device 1 is notified that congestion has occurred. In this case, since the resource management device 2 detects the occurrence of congestion before paying out the last one from the resource pool 40, the last one is not actually paid out.

  Subsequently, the traffic control device 1 that has received the notification of the occurrence of congestion performs call restriction control that limits the number of incoming calls to the congestion area in order to eliminate the congestion. Hereinafter, two control methods for eliminating congestion will be described.

<First control method>
FIG. 6 is a flowchart showing processing of the first control method for performing call restriction.

  The resource information acquisition unit 11 of the traffic control device 1 waits for notification that the congestion has been detected from the resource management device 2 in step S101 (No in step S101), and if notification is received that congestion has been detected. (Yes in step S101) The process proceeds to step S102 to start the congestion control process.

  In step S102, the ground-specific traffic information acquisition unit 12 acquires ground-specific traffic information 92 (see FIG. 4) from the traffic monitoring device 3, and in the next step S103, the total control amount determination unit 13 acquires the acquired ground The congestion area is specified by comparing the most recent outgoing call count and the most busy outgoing call count for each incoming area included in the separate traffic information 92 according to a predetermined standard. For example, an area where the number of the latest outgoing calls is more than twice the number of the most busy outgoing calls is extracted as a congestion area. At this time, one or more congestion areas are usually extracted, but if there is a traffic increase of less than twice in many incoming areas, no congestion area may be extracted. In this case, the entire incoming area is specified as a congestion area.

  Next, in step S104, the resource information acquisition unit 11 acquires the resource information 91 (see FIG. 3) from the resource management device 2, and in the next step S105, the total control amount determination unit 13 (Expression 1) Thus, the value of the total control amount is calculated using the number of session control devices included in the acquired resource information 91 and the ground-specific traffic information 92 acquired in step S102.

Total control amount = number of session control devices x maximum number of calls that can be processed
-Total number of incoming and outgoing calls outside the most congested area (Equation 1)

  Here, the maximum number of calls that can be processed is the maximum number per minute that one session control device 4S can process a connection request. In step S105, a connection request between subscribers outside the congestion area is processed. The total amount of control is calculated on the assumption that all the resources except for the resources to be allocated are allocated to the processing of connection requests addressed to subscribers in the congested area.

  Next, in step S106, the control total amount determining unit 13 performs only the connection request to the subscriber terminal 7 in the congested area based on the resources and the control total amount allocated to the operating session control device 4S. By determining the device 4S and allocating the total control amount to the determined session control device 4S, the call restriction value instructed to each session control device 4S is determined.

Specifically, the control total amount determination unit 13 transmits an inquiry signal including the calculated control total amount to the resource management device 2.
When the resource management device 2 receives the inquiry signal, the resource management device 2 selects the session control device 4S having a resource (maximum value that can be called by the session control device 4S) that matches the total control amount included in the received inquiry signal. The session control device 4S and the resource of the session control device 4S are transmitted as response signals to the control total amount calculation unit 13.
For example, when the total control amount is 1000, the resource management device 2 can select a combination of the session control devices 4S that minimizes the sum of the resources to 1000 or more from the plurality of session control devices 4S.
When receiving the answer signal, the total control amount determining unit 13 determines the session control apparatus 4S included in the answer signal as the session control apparatus 4S that only makes a connection request to the subscriber terminal 7 in the congestion area. By allocating the total control amount according to the resources of the session control device, the call restriction value instructed to each session control device 4S is determined.

  Next, in step S107, the control instruction unit 14 transmits control instruction information (call restriction instruction information) for instructing the calculated call restriction value to each session control device 4S, and then waits for a predetermined time. .

  According to such an operation, for example, as shown in FIG. 7, when congestion occurs in an incoming call to the subscriber terminal 7 in the area A, the traffic control device 1 performs two operations as shown in FIG. 8. Only the connection request to the subscriber terminal 7 in the congested area is made to the session control device 4S.

  In addition, the total control amount was allocated to the connection request (excluding the connection request to the subscriber terminal 7 in the congested area) made by the right two session control devices 4S before the total control amount was allocated (see FIG. 7). Later (see FIG. 8), as a method of allocating to the two session control devices 4S on the left, for example, Irie, four others, “A study on dynamic configuration change in a scale-out type session control server”, electronic information communication Academic Society, IEICE Technical Report NS2010-236, March 2011, p. Known methods such as the method described in 407-410 can be adopted.

  Next, in step S108, the ground-specific traffic information acquisition unit 12 acquires the latest ground-specific traffic information 92 from the traffic monitoring device 3, and in step S109, the resource information acquisition unit 11 receives information from the resource management device 2. The latest resource information 91 is acquired.

  Next, in step S110, the control total amount determination unit 13 determines whether or not congestion has been resolved by using the acquired latest ground-specific traffic information 92 or the latest resource information 91, and the congestion has not been eliminated. If this is the case (No in step S110), the process returns to step S105 and the above process is repeated. On the other hand, if the congestion is resolved (Yes in step S110), the process proceeds to step S111. At this time, the determination as to whether or not the congestion has been resolved may be made by determining whether or not the number of outgoing calls addressed to all incoming areas has become equal to or less than the number of outgoing calls during the most busy time. This may be done by determining whether the ratio of the number of pools is 20% or more of the total number of resources, for example.

  In step S111, the control instruction unit 14 transmits a call restriction release instruction to each session control device 4S, and then ends a series of processes.

According to the first control method described above, resources can be dynamically managed and distributed in congestion control, and the session control device 4S that performs congestion control can be aggregated, so that network resources can be suitably used. it can.
It also maximizes the number of connections for calls to subscribers in congested areas when congestion occurs because the maximum available resources are allocated for processing connection requests addressed to subscribers in congested areas. can do.

<Second control method>
FIG. 9 is a flowchart showing processing of the second control method for performing call restriction.

  The processing from step S201 to step S204 is the same as the processing from step S101 to step S104 of the first control method described above, except that the resource information 91 acquired in step S204 is stored in the storage means. The same.

  Next, in step S205, the total control amount determination unit 13 calculates the value of the total control amount using the ground-specific traffic information 92 acquired in step S202 according to (Equation 2). Note that the value of the total control amount calculated here is stored in the storage means.

    Total control amount = Number of incoming calls to the most congested area (Equation 2)

  In this step S205, the number of incoming calls addressed to the subscriber in the latest congestion area is set to the first control total amount.

  Next, in step S206, the control total amount determination unit 13 determines the call restriction value instructed to each session control device 4S by the same method as in step S106.

  Next, in step S207, the control instruction unit 14 transmits control instruction information (call restriction instruction information) for instructing the calculated call restriction value to each session control device 4S, and then waits for a predetermined time. . Next, in step S <b> 208, the resource information acquisition unit 11 acquires the latest resource information 91 from the resource management device 2. The resource information 91 acquired here is stored in the storage means.

  Next, in step S209, the control total amount determination unit 13 determines whether or not congestion has been eliminated using the latest resource information 91. If the congestion has not been eliminated (No in step S209), step S210 is performed. If the congestion is resolved (Yes in step S209), the process proceeds to step S211. At this time, whether or not the congestion has been resolved is determined by determining whether or not the ratio of the number of pools of the resource pool 40 is, for example, 20% or more of the total number of resources.

  In step S210, the control total amount determination unit 13 uses the previous control total amount and the previous resource information 91 stored in the storage unit according to (Equation 3) and the value of the control total amount using the resource information 91 acquired this time. Is calculated.

Total control amount = previous total control amount × current resource allocation rate to the session control device
/ Previous resource allocation rate to session control unit (Equation 3)

  In this step S210, a value obtained by multiplying the previous control total amount by the rate of change in the resource allocation rate to the session control device (resource increase / decrease rate) is calculated as a new current control total amount (see FIG. 9 for details). Will be described later.) After that, the total control amount determination unit 13 returns the process to step S206 and repeats the above process.

  In step S211, the control instruction unit 14 transmits a call restriction release instruction to each session control device 4S, and then ends a series of processes.

  Here, the transition of the total control amount by the second control method will be described with reference to FIG. FIG. 10 is a transition example of the total control amount by the second control method. Here, it is assumed that the initial control total amount is set to C as a result of detecting the occurrence of congestion at time t. Further, the recalculation of the total control amount is performed every Δt, and the resource allocation rate (SC resource allocation rate) to the entire session control device 4S is changed so that the free resource rate becomes 10% or more. It is assumed that the resource allocation rate for the entire 4N (NSC resource allocation rate) is not controlled.

  First, at time t, occurrence of congestion is detected, and the initial total control amount is determined as C. At this time, the SC resource allocation rate is 60%, the NSC resource allocation rate is 30%, and the free resource rate is 10%.

  At time t + Δt, as a result of an increase in the load on non-session services, the NSC resource allocation rate increased to 35% and the free resource rate decreased to 5%. Therefore, the resource management device 2 reduces the SC resource allocation rate to 55% in order to increase the free resource rate to 10%. Accordingly, the total control amount is reset to C × 55/60.

  At time t + 2Δt, the load on the non-session service decreased. As a result, the NSC resource allocation rate decreased to 30% and the free resource rate increased to 15%. Therefore, the resource management device 2 increases the SC resource allocation rate to 60% so that the free resource rate becomes 10%. Accordingly, the total control amount is reset to (C × 55/60) × 60/55 = C.

  At time t + 3Δt, since the NSC resource allocation rate remains 30%, the SC resource allocation rate is maintained at 60%, the free resource rate is maintained at 10%, and the total control amount remains C.

  At time t + 4Δt, the load on the non-session service has increased again. As a result, the NSC resource allocation rate has increased to 35%. However, the number of outgoing calls addressed to the congested area decreases, and the SC resource is controlled by the resource management device 2. The allocation rate decreased to 50% and the free resource rate increased to 15%. Accordingly, the total control amount is reset to C × 50/60.

  At time t + 5Δt, the NSC resource allocation rate remained at 35%, but the number of outgoing calls addressed to the congested area further decreased, and the SC resource allocation rate decreased to 45% under the control of the resource management device 2 The free resource rate has returned to 20%, which is the standard for canceling call regulation. Accordingly, the call restriction is canceled and a series of control is completed.

  According to the second control method described above, the initial total control amount for the congested area is set to the number of outgoing calls destined for the area immediately before the congestion occurs, and thereafter, the resource by the follow-up control to the actual traffic fluctuation. The total control amount is changed in proportion to the increase / decrease of the allocation rate. Therefore, it is possible to perform control conforming to changes in the resource state with high followability to actual traffic fluctuations.

  Subsequently, when communication between the traffic control device 1 and the resource management device 2 is interrupted due to a failure of the resource management device 2 or a network failure, the third control for detecting the occurrence of congestion and eliminating it. A method will be described.

<Third control method>
FIG. 11 is a flowchart showing the process of the third control method for the traffic control device 1 to detect the occurrence of congestion and perform call restriction.

  In step S301, the resource information acquisition unit 11 of the traffic control device 1 determines whether or not communication with the resource management device 2 is possible. If communication is possible (Yes in step S301), the process ends. On the other hand, if communication with the resource management device 2 is not possible (No in step S301), the process proceeds to step S302 to start the congestion monitoring process.

  In step S302, the traffic control device 1 acquires information on the session control device group 40S operating at that time. The information acquired here includes address information for individually communicating with all the session control devices 4S that are in operation, whereby the traffic control device 1 knows the number of session control devices 4S that are in operation. These pieces of information may be acquired from the load balancer 5 or the traffic monitoring device 3, or a broadcast notification signal for requesting acquisition of information is transmitted to all the session control devices 4S to individually acquire the information. May be.

  Next, in step S303, the ground-specific traffic information acquisition unit 12 acquires ground-specific traffic information 92 (see FIG. 4) from the traffic monitoring device 3, and in the next step S304, the control total amount determination unit 13 As described in step S103 of FIG. 6, the congestion area is specified using the acquired traffic information 92 by ground. If no congestion has occurred, it is determined that there is no congestion area.

  Next, in step S305, the control total amount determination unit 13 determines whether or not congestion has occurred depending on whether or not a congestion area has been specified. If no congestion has occurred (No in step S305), step The processing is returned to S301 and the above processing is repeated. On the other hand, if congestion has occurred (Yes in step S305), the process proceeds to step S306.

  Next, in step S306, the total control amount determination unit 13 calculates the value of the total control amount using the ground-specific traffic information 92 acquired in step S303 according to the above (Equation 2). In step S303, the number of incoming calls addressed to the subscriber in the latest congestion area is set as the total control amount.

  Next, in step S307, the total control amount determination unit 13 calculates a call restriction value instructing each session control device 4S by the same method as in step S106.

  Next, in step S308, the control instruction unit 14 transmits control instruction information (call restriction instruction information) for instructing the calculated call restriction value to each session control device 4S, and then waits for a predetermined time. . Next, in step S <b> 309, the ground-specific traffic information acquisition unit 12 acquires the latest ground-specific traffic information 92 from the traffic monitoring device 3.

  Next, in step S310, the control total amount determination unit 13 determines whether or not the congestion has been solved by using the acquired latest ground-specific traffic information 92, and if the congestion has not been solved (in step S310). No) The process proceeds to step S311, and after waiting for a predetermined time, the process returns to step S309 and the above process is repeated. On the other hand, if the congestion is resolved (Yes in step S310), the process proceeds to step S312. At this time, whether or not the congestion has been resolved is determined by determining whether or not the number of outgoing calls addressed to all the incoming areas is equal to or less than the number of outgoing calls during the most busy time.

  In step S312, the control instruction unit 14 transmits a call restriction release instruction to each session control device 4S, and then returns to step S301 to repeat the above process.

  According to the third control method described above, even when resource control by the resource management device 2 does not function properly, the traffic control device 1 and the traffic monitoring device 3 cooperate to detect occurrence of congestion. At the same time, by implementing the call restriction that secures the number of incoming calls to the congestion area immediately before the congestion occurs, the congestion control utilizing the resources of the session control device 4S operating at that time is realized. Can do.

  In addition, the traffic control apparatus 1 can be realized by causing a computer having a communication interface to execute a traffic control program that performs the processes of the first to third control methods described above. This traffic control program can be provided via a communication line, or can be written and distributed on a recording medium such as a CD-ROM (Compact Disc-Read Only Memory).

  Although the description of the embodiment of the present invention has been completed above, the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in steps S104, S204, and S302, the traffic control device 1 receives a signal corresponding to the answer signal transmitted from the resource management device 2, and in steps S106, S206, and S307, generates a signal based on the signal. It may be configured to determine a call restriction value.

DESCRIPTION OF SYMBOLS 1 Traffic control apparatus 11 Resource information acquisition part 12 Traffic information acquisition part according to ground 13 Control total amount determination part 14 Control instruction | indication part 2 Resource management apparatus 21 Resource control part 22 Resource monitoring part 23 Congestion detection part 3 Traffic monitoring apparatus 31 Traffic information according to ground Aggregation section 4 General-purpose computer (control device)
41 connection request processing unit 42 outgoing call restriction unit 43 CPU utilization rate measurement unit 44 incoming / outgoing call number information collection unit 4S session control device 4N non-session control device 40S session control device group 40N non-session control device group 5 load balancer 6 location server 7 Subscriber terminal (terminal)
8 IP network 91 Resource information 92 Traffic information by ground

Claims (6)

A plurality of computers, which are resources necessary for providing various communication services to terminals connected to a communication network;
Each of the plurality of computers is operated as one of a session control device that receives a connection request from a terminal and performs connection processing between terminals, and a non-session control device that performs processing other than connection processing between terminals, Alternatively, a resource management device that allocates resources according to changes in service load by waiting in a resource pool;
A traffic control device that transmits an instruction to limit the number of connection requests accepted to a terminal in the specific region to the session control device when congestion occurs in the specific region of the communication network;
The traffic control device of a communication control system comprising:
Resource information including the number of operating session control devices and the number of non-session control devices is acquired from the resource management device, and congestion control processing is performed when the resource pool resource becomes insufficient. A resource information acquisition unit for starting
A traffic information acquisition unit for each ground that acquires traffic information for each ground including information summing up the number of outgoing calls and the number of incoming calls for each incoming region of the session control device;
The congestion area in which the number of outgoing calls by the latest incoming area exceeds a predetermined standard from the ground traffic information is specified, and the identified resource information and the acquired traffic information are used to identify the congestion area. A total control amount that is the upper limit of the total number of connection requests received to terminals in a congested area is determined, and the determined total control amount is distributed to the session control devices that are in operation to be the upper limit of the number of connection request receptions. A total control amount determining unit for determining a regulation value;
A control instruction unit that transmits call restriction instruction information including the determined call restriction value to the session control device;
With
The total control amount determination unit determines and determines the session control device that performs only a connection request to a terminal in the congestion area based on the resources allocated to the session control device in operation and the total control amount. The traffic control device, wherein the total control amount is distributed to the session control device. The traffic control device according to claim 1,
When the congestion control process is started, every predetermined time,
The resource information acquisition unit acquires the latest resource information,
The ground-specific traffic information acquisition unit acquires the latest traffic-specific traffic information,
The total control amount determination unit obtains the latest acquired number from the value obtained by multiplying the number of the active session control devices included in the acquired most recent resource information by the maximum number of calls that can be processed per device. A traffic control device, wherein a value obtained by subtracting the total number of outgoing / incoming calls between terminals other than the congestion area obtained from the ground-specific traffic information is determined as the total control amount. The traffic control device according to claim 1,
The resource information acquisition unit stores the acquired resource information in a storage unit,
At the start of the congestion control process,
The total control amount determination unit determines the latest number of incoming calls to the congestion area obtained from the acquired traffic information according to the ground as the total control amount, and stores the value in the storage unit,
After that, every predetermined time,
The resource information acquisition unit acquires the latest resource information,
The total control amount determination unit, from the number of the session control devices that are in operation included in the most recent acquired resource information, and the number of previous session control devices stored in the storage unit, The resource increase / decrease rate indicating the increase / decrease rate of the resource allocation rate allocated to the session control device is calculated, and the value of the previous control total amount stored in the storage means is calculated as the calculated resource increase / decrease rate value. A traffic control device, wherein the multiplied value is determined as the total control amount for this time. The traffic control device according to claim 1,
When the resource information acquisition unit determines that the resource information cannot be acquired from the resource management device, the ground-specific traffic information acquisition unit acquires the ground-specific traffic information, and the control total amount determination unit Start the congestion monitoring process to detect the presence or absence of congestion by specifying the congestion area where the number of outgoing calls for each incoming area exceeds the predetermined standard from the traffic information by ground,
When the occurrence of congestion is detected by the congestion monitoring process, the total control amount determination unit determines the number of incoming calls closest to the congestion area obtained from the ground-specific traffic information as the total control amount. A traffic control device. A plurality of computers, which are resources necessary for providing various communication services to terminals connected to a communication network;
Each of the plurality of computers is operated as one of a session control device that receives a connection request from a terminal and performs connection processing between terminals, and a non-session control device that performs processing other than connection processing between terminals, Alternatively, a resource management device that allocates resources according to changes in service load by waiting in a resource pool;
A traffic control device that transmits an instruction to limit the number of connection requests accepted to a terminal in the specific region to the session control device when congestion occurs in the specific region of the communication network;
A traffic control method for the traffic control device of a communication control system comprising:
Resource information including the number of operating session control devices and the number of non-session control devices is acquired from the resource management device, and congestion control processing is performed when the resource pool resource becomes insufficient. The step of starting
Obtaining ground-specific traffic information including information summing up the number of outgoing calls and the number of incoming calls for each incoming area of the session control device;
The congestion area in which the number of outgoing calls by the latest incoming area exceeds a predetermined standard from the ground traffic information is specified, and the identified resource information and the acquired traffic information are used to identify the congestion area. A total control amount that is the upper limit of the total number of connection requests received to terminals in a congested area is determined, and the determined total control amount is distributed to the session control devices that are in operation to be the upper limit of the number of connection request receptions. Determining the regulatory value;
Transmitting call restriction instruction information including the determined call restriction value to the session control device;
Including
When allocating the determined control total amount to the operating session control measures, the control total amount determining unit is configured to determine whether the congestion area is based on the resources allocated to the operating session control device and the control total amount. A traffic control method comprising: determining the session control device that performs only a connection request to a terminal, and allocating the total control amount to the determined session control device.   A traffic control program for causing a computer to function as the traffic control device according to any one of claims 1 to 4.

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