JP5695584B2 - Congestion control device, congestion control system, and congestion control method - Google Patents

Description

  The present invention relates to a congestion control device, a congestion control system, and a congestion control method for controlling a call by determining a total traffic control amount in real time in a congestion countermeasure when a communication service is performed via a network.

In recent years, in order to prevent congestion when performing communication services via a network, it has become possible to determine and control the total amount of traffic control in real time.
In Patent Document 1 (Japanese Patent No. 2794659), in the PSTN (Public Switched Telephone Networks) which is a public switched telephone network, it is difficult to communicate due to concentration of incoming calls or the like. An invention of a method for controlling an outgoing call to a region is described. In this control method, the total number of calls communicated to the ground (total number of calls) is allocated to each exchange on the calling side, and then the number of outgoing calls exceeding the allocation value is regulated in each exchange to distribute the total traffic. Optimized. Patent Document 1 further describes that the distribution value is calculated by ((number of connectable calls) × (number of outgoing calls in the transmission area) / (total number of calls)).

  In congestion control of IP (Internet Protocol) telephone network CTI-GW (Computer Technology Integration Gateway) or soft switch (hereinafter sometimes referred to as "session control device") In order to stop the inflow of calls at the entrance of the network, the congestion control device allocates the total number of calls (total control amount) communicated per unit time to the session control device on the originating side. Furthermore, each session control device controls the number of outgoing calls exceeding the value (control amount) allocated per unit time in a cycle of this unit time.

FIG. 6 is a diagram showing the configuration and operation of the congestion control system in the comparative example.
The congestion control system 1A includes a network control terminal 10, a congestion control device 20A, session control devices 30-1 to 30-6, and a plurality of user terminals 40. Note that the session control devices 30-1 to 30-6 are simply referred to as the session control device 30 when they are not particularly distinguished.
The network control terminal 10 is connected to the congestion control device 20A. The congestion control device 20A is connected to the session control devices 30-1 to 30-6 via a network. The session control devices 30-1 and 30-2 are connected to the session control device 30-5. The session control devices 30-3 to 30-5 are connected to the session control device 30-6. Furthermore, each of the session control devices 30-1 to 30-6 is connected to the user terminal 40 and accommodates them.

In FIG. 8, the session control device 30-1 shows a radial icon with “congestion” on the top, indicating that congestion has occurred.
When the occurrence of congestion is detected, the network control terminal 10 instructs the total amount of control to the congestion control device 20A in step S1.
In step S2, the congestion control device 20A distributes the instructed control total amount to each session control device 30, and calculates each control amount.
In step S3, the congestion control device 20A instructs each session control device 30 on the allocated control amount.
In step S4, each session control device 30 limits outgoing calls exceeding the instructed control amount. In FIG. 8, the session control devices 30-2 to 30-6 are indicated by an icon with a horizontal line in a circle at the top, indicating that the call is restricted.
Thus, the congestion control system 1A of the comparative example performs congestion control based on the instructed total control amount.

  Further, in Patent Document 2 (Japanese Patent No. 3715604) and Patent Document 3 (Japanese Patent Laid-Open No. 2004-304646), there is a possibility that the soft switch may stop functioning due to the concentration of many calls in the IP telephone system. In order to deal with a certain congestion, the number of calls connected is controlled based on the detecting means for determining that the number of calls monitored is more than the threshold number of calls and the density of the number of calls per unit time. An invention of a congestion control method for executing control means is described. Further, Patent Document 2 describes that call density control is performed on an INVITE signal in SIP (Session Initiation Protocol).

  Patent Document 4 (Japanese Patent Application Laid-Open No. 5-022407) describes a method in which an exchange that detects congestion synergizes regulation information with a response signal such as a common line signal system and a backward signal such as a disconnection signal. The invention to notify the originating exchange is described. Further, in the invention of Patent Document 4, the originating exchange starts regulation control according to the instruction of the regulation information, and then the congestion exchange changes the regulation amount based on the congestion state, or the originating exchange exchanges the originating exchange. The regulation amount is changed based on the information obtained from the side exchange. In this way, the invention of Patent Document 4 automatically performs the congestion control by the feedback control of both the originating and terminating exchanges.

As a basic concept of congestion control, there is “maximum utilization of network resources”. This is intended to maximize the call communication rate even during congestion control.
As described in Non-Patent Document 1, call density control, which is a conventional technique, has the property that the number of communication calls is less than the control amount when the call generation amount is four times or less than the control amount. ing. This property is derived from the characteristics of call density control as being obvious.

  FIGS. 7A and 7B are diagrams showing the operation of the session control apparatus in the comparative example.

  FIG. 7A is a diagram illustrating a relationship between a connection call and a control pass call in the session control device 30. The lower arrow indicates a connected call. The upper arrow indicates a control pass call. The connection call to which the “x” mark is given indicates that it is restricted. Here, in the session control device 30, the number of calls is designated as a control amount in a 2-second cycle. The session control device 30 controls the connection calls so that the number of control passing calls is equal to or less than the number of calls for every 2 seconds.

  FIG. 7B is a diagram illustrating a relationship between a connection call and a control pass call in the session control device 30. The leftmost is the first period, and is shown in order on the right side up to the fourth period. In FIG. 7 (b), unlike FIG. 7 (a), no connection call is generated in the third period. At this time, the resource of the control amount = 1 call is not used, and is therefore a useless resource.

Japanese Patent No. 2749659 Japanese Patent No. 3715604 JP 2004-304646 A JP-A-5-022407

Hirofumi Tokunaga, Hiromichi Kawano, "Traffic congestion control based on call density control", IEICE Transactions B, IEICE, March 1998, Vol.J71-B, No.3, pp.322- 329

FIG. 8 is a diagram illustrating the relationship between the ratio of the number of generated calls and the ratio of the number of communication calls with respect to the control amount.
The horizontal axis in FIG. 8 indicates the ratio of the number of generated calls to the control amount. Hereinafter, this ratio may be referred to as the “number of calls generated”. The vertical axis in FIG. 8 indicates the ratio of the number of communication calls to the control amount. Hereinafter, this ratio may be referred to as “communication call number ratio”.
The broken line is an ideal value of the communication call rate ratio with respect to the generated call rate ratio. The solid line is the theoretical value of the communication call ratio with respect to the generated call ratio in the comparative example. The hatched portion indicates the difference between the ideal value and the theoretical value.
This theoretical value is derived from Equation 1 below.

As indicated by the broken line, the ideal value is that when the ratio of the number of generated calls is 1 or less, the ratio of the number of generated calls is equal to the ratio of the number of communication calls, and when the ratio of generated calls exceeds 1, the ratio of the number of communication calls is 1 It is limited to. At this time, the total control resource of the network is most effectively used.
However, in actuality, as indicated by the solid line, the number of communication calls is lower than the ideal value, so the network total control resource may not be used effectively. For example, this becomes noticeable before the congestion control is canceled when the congestion tends to be calm.

FIG. 9 is a diagram showing the elapsed time of the number of generated calls and the number of communication calls in the comparative example.
The horizontal axis in FIG. 9 indicates time, and the vertical axis in FIG. 9 indicates the number of calls. The upper solid line indicates the number of generated calls, and the lower solid line indicates the number of communication calls. The broken line indicates the total control amount. An ellipse indicates a period to be a problem in the present invention.
Thus, in the congestion control of the comparative example, there is a problem that when the number of generated calls approaches the control amount, the control amount that is a network resource cannot be utilized. This problem is particularly noticeable when the generated call volume is 1.0 to 4.0 times the control volume.

  Therefore, an object of the present invention is to provide a congestion control device that calculates an optimal control amount and improves a call communication rate.

In order to solve the above-described problem, in the invention according to claim 1, traffic volume collecting means for collecting the number of generated calls from each session control device to a predetermined area, and the sum of the generated calls to the predetermined area. By obtaining an adjustment value by the ratio of generated calls divided by the total control amount, allocating the total control amount to the predetermined area to the session control devices according to the number of generated calls, and multiplying the adjustment value, It includes a control amount calculating means for calculating a control amount for the next cycle of the control device, so as to regulate a call to the predetermined area in the control amount of the next cycle, and a instructing means for instructing said each session controller And the congestion control device is characterized in that, when the generated call ratio is any one of 1.1 to 4.0, the adjustment value is any one of 1.0 to 5.67. did.

In the fifth aspect of the present invention, a traffic volume collecting step for collecting the number of calls generated from each session control device to a predetermined area, and the number of calls generated by dividing the sum of the generated calls by the total control amount for the predetermined area. An adjustment value calculating step for obtaining an adjustment value by a ratio, and distributing the control total amount to the predetermined area to the session control devices according to the number of generated calls, and multiplying the adjustment value, a control amount calculation step of calculating a control amount for the next period, the call to a predetermined region so as to regulate the control of said next cycle, run, and instruction step of instructing the respective session control unit, the generator The congestion control method is characterized in that when the call ratio is any of 1.1 to 4.0, the adjustment value is any of 1.0 to 5.67 .

In this way, the optimal control amount can be calculated and the call communication rate can be improved. Further, compared with the proportion of the number of calls generated, the total control value can be effectively used by (adjustment value−1.0).

The invention according to claim 3 further comprises storage means for storing an adjustment value table indicating a relationship between the generated call ratio and the adjustment value, and the control total amount calculation means is further based on the adjustment value table. , from the generation call ratio, to obtain the adjustment value, and the congestion control apparatus according to claim 1 or claim 2, characterized in that.

  In this way, the adjustment value can be easily obtained simply by referring to the adjustment value table.

  In the second aspect of the present invention, traffic volume collecting means for collecting the number of calls generated from each session control device to a predetermined area, and the number of calls generated by dividing the sum of the generated calls by the total control amount for the predetermined area A control value for the next period of the session control device is obtained by obtaining an adjustment value by a ratio, allocating the total control amount to the predetermined area to each session control device according to the number of generated calls, and multiplying the adjustment value. A control total amount calculating means for calculating the control information, and an instruction means for instructing each session control device to regulate a call to the predetermined area by the control amount of the next period, the control total amount calculating means Further, the total number of generated calls is divided by the total control amount to calculate the ratio of generated calls, 1.0 is subtracted from the adjustment value, and divided by the adjustment value to obtain a logarithm. Adjustment value and minus A value obtained by multiplying a .0 to calculate the adjustment value such that the generated call number ratio, was congestion controller, characterized in that.

  In this way, the optimal control amount can be calculated and the call communication rate can be improved. Furthermore, the adjustment value can be obtained more accurately than the adjustment value is calculated using the adjustment value table.

  In a sixth aspect of the present invention, a traffic volume collecting step for collecting the number of generated calls from each session control device to a predetermined area, and the number of generated calls obtained by dividing the sum of the generated calls by the total control amount to the predetermined area. An adjustment value calculating step for obtaining an adjustment value by a ratio, and distributing the control total amount to the predetermined area to the session control devices according to the number of generated calls, and multiplying the adjustment value, A control total amount calculating step for calculating a control amount for the next period; and an instruction step for instructing each session control device to regulate a call to the predetermined area with the control amount for the next period. Further, in the total amount calculating step, the total number of generated calls is divided by the total control amount to calculate the ratio of generated calls, and 1.0 is subtracted from the adjustment value and divided by the adjustment value. Take the number, further a value obtained by multiplying the corresponding adjustment value and a minus 1.0 to calculate the adjustment value such that the generated call number ratio, was congestion control method characterized by.

In this way, the optimal control amount can be calculated and the call communication rate can be improved. Furthermore, the adjustment value can be obtained more accurately than the adjustment value is calculated using the adjustment value table.

According to a fourth aspect of the present invention, there are provided call restriction means for restricting outgoing calls to the predetermined area with the instructed control amount, and traffic amount aggregation means for totalizing and notifying the number of generated calls. A congestion control system comprising: a session control apparatus having the above-described configuration; and the congestion control apparatus according to any one of claims 1 to 3 .

  By doing in this way, the outgoing call to a predetermined area can be regulated by the control value of each session control device calculated by this congestion control device.

  According to the present invention, it is possible to provide a congestion control device that calculates an optimal control amount and improves a call communication rate.

It is a schematic block diagram which shows the congestion control system in this embodiment. It is a figure which shows each part structure of the congestion control system in this embodiment. It is a figure which shows the relationship between the generated call number ratio and adjustment value in this embodiment. It is a sequence diagram of congestion control in this embodiment. It is a flowchart which shows the congestion control process in this embodiment. It is a figure which shows the structure and operation | movement of a congestion control system in a comparative example. It is a figure which shows operation | movement of the session control apparatus in a comparative example. It is a figure which shows the relationship between the ratio of the number of generated calls with respect to control amount, and the ratio of the number of communication calls. It is a figure which shows the time passage of the number of generated calls and the number of communication calls in a comparative example.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

(Configuration of this embodiment)

FIG. 1 is a schematic configuration diagram showing a congestion control system in the present embodiment.
The congestion control system 1 includes a network control terminal 10, a congestion control device 20, session control devices 30-1 to 30-6, and a plurality of user terminals 40. Note that the session control devices 30-1 to 30-6 are simply referred to as the session control device 30 when they are not particularly distinguished.
The network control terminal 10 is connected to the congestion control device 20. The congestion control device 20 is connected to the session control devices 30-1 to 30-6 via a network. The session control devices 30-1 and 30-2 are connected to the session control device 30-5. The session control devices 30-3 to 30-5 are connected to the session control device 30-6. The session control device 30-6 is connected to the other network 100. Furthermore, each of the session control devices 30-1 to 30-6 is connected to the user terminal 40 and accommodates them.

The congestion control system 1 shown in FIG. 1 has only a soft switch that performs session control, but is not limited thereto.
The user terminal 40 is, for example, an IP phone or a fixed phone, and performs communication by an outgoing call from the user terminal 40 to another terminal and an incoming call from the other terminal to the user terminal 40.
The session control device 30 is a so-called soft switch, and controls to connect a new connection request transmitted from the accommodated user terminal 40 to a target destination.
The congestion control device 20 controls the call control of the session control device 30 and suppresses congestion of the network.

FIG. 2 is a diagram showing a configuration of each part of the congestion control system in the present embodiment.
The congestion control system 1 includes a congestion control device 20, a congestion session control device 30-m, and call restriction session control devices 30-1 to 30-n. The congestion control device 20 is connected to a congestion session control device 30-m and outgoing call restriction session control devices 30-1 to 30-n. The call control session control devices 30-1 to 30-n and the congestion session control device 30-m are session control devices 30 having the same configuration. Note that the congestion control system 1 in FIG. 2 is limited to the congestion control device 20 and the session control device 30 that is a soft switch.

The congestion session control device 30-m accommodates, for example, an external terminal located in the affected area and is congested.
The call control session control devices 30-1 to 30-n are session control devices 30 that perform call control according to the control amount of each cycle, and are located within or outside the affected area.

  The congestion session control device 30-m and the call restriction session control devices 30-1 to 30-n have the same configuration. In FIG. 2, the congestion session control device 30-m mainly shows a part related to congestion monitoring and a call restriction request. In the call restriction session control devices 30-1 to 30-n, parts related to call restriction are shown.

<< Configuration of Congestion Control Device 20 >>
The congestion control device 20 includes a processing unit 21, a control instruction unit 26, and a DB (Database) unit 27. The processing unit 21 includes a control code determination unit 22, a traffic amount collection unit 23, and a control instruction information determination unit 24. The control instruction information determination unit 24 includes a total control amount calculation unit 25.

The processing unit 21 is realized, for example, by a CPU (Central Processing Unit) reading a software program stored in a storage unit (not shown) into a RAM (Random Access Memory) and executing it.
The control code determination unit 22 determines how to allocate the specified total control amount to the call control session control devices 30-1 to 30-n.
The traffic volume collection unit 23 (traffic volume collection means) collects information on the number of outgoing calls in the cycle from the traffic volume totaling unit 33 of the session control device 30 described later, and further, the cycle of the entire communication network. This sums up the total number of outgoing calls.

The control instruction information determination unit 24 determines detailed instruction contents including a control amount (a destination device, a target telephone number, etc.) and makes an instructionable state. That is, the control instruction information determination unit 24 determines the session control device 30 related to the control amount based on the instruction content including the control amount distributed by the total control amount calculation unit 25, and transmits the session control device 30 to the session control device 30. Create a packet.
The total control amount calculation unit 25 (total control amount calculation means) determines a control amount to be distributed to each session control device 30. That is, the total control amount calculation unit 25 distributes the control amount to each session control device 30. Further, the total control amount calculation unit 25 obtains an adjustment value α by the generated call number ratio x obtained by dividing the total number of generated calls of each session control device 30 by the total control amount for a predetermined area. The total control amount calculation unit 25 calculates the control amount for the next period of the session control device 30 by multiplying the control amount distributed to each session control device 30 by the adjustment value α.

  The control instruction unit 26 (instruction means) transmits an instruction to each session control device 30. That is, the control instruction unit 26 transmits the instruction content determined by the control instruction information determination unit 24 to the session control device 30 related to the instruction content. The control instruction unit 26 is connected to the call restriction unit 31 of each session control device 30. The control instruction information determination unit 24 and the control instruction unit 26 are instruction units that instruct the session control device 30 to regulate outgoing calls with the allocated control amount.

The DB unit 27 is a storage unit that stores a database. The database stores, for example, number sections, city code numbers, and city code numbers of each region. Furthermore, the DB unit 27 stores data necessary for congestion control, such as the adjustment value table 28 and information on the network configuration (for example, the number and location information of the session control devices 30).
The adjustment value table 28 is a table in which the relationship between the generated call number ratio x and the adjustment value α is described. The adjustment value table 28 is used when the control total amount calculation unit 25 acquires the adjustment value α from the generated call number ratio x. The adjustment value table 28 will be described with reference to FIG.

<< Configuration of Session Control Device 30 >>
As shown by the call restriction session control devices 30-1 to 30-n, the session control device 30 includes a call restriction unit 31, a connection request processing unit 32, and a traffic amount totaling unit 33, and congestion session control. As shown by the device 30-m, a call restriction request unit 34 and a resource monitoring unit 35 are provided. Further, the resource monitoring unit 35 includes a CPU usage rate measuring unit 36. Here, the session control device 30 is both the call restriction session control devices 30-1 to 30-n and the congestion session control device 30-m.

<< Configuration of Call Control Session Control Apparatuses 30-1 to 30-n >>
The call restriction unit 31 receives the instruction content transmitted by the control instruction unit 26 of the congestion control device 20, and restricts the outgoing call in the next cycle with a control amount based on the instruction content. The outgoing call restriction unit 31 does not restrict outgoing calls to areas other than the congestion area.

  The connection request processing unit 32 processes a connection request (outgoing call) of the user terminal 40 connected to the session control device 30. Further, the connection request processing unit 32 transmits a connection request transmitted from the user terminal 40 accommodated by the session control device 30 itself and the session control device 30 from another session control device 30 in the network. It handles both connection requests.

The traffic amount totaling unit 33 collects and aggregates information on the number of outgoing calls in the period of the session control device 30 and transmits the collected information to the traffic amount collection unit 23 of the congestion control device 20.
The congestion session control device 30-m also includes a call restriction unit 31 (not shown), a connection request processing unit 32, and a traffic amount totaling unit 33 (not shown).

<< Configuration of Congestion Session Control Device 30-m >>
When the session control device 30 detects congestion, the call restriction request unit 34 requests the congestion control device 20 to restrict the call from the communication network.
The resource monitoring unit 35 monitors resources (memory, storage capacity, CPU, communication bandwidth, etc.) of the session control device 30, and detects congestion by monitoring the resources. The resource monitoring unit 35 includes a CPU usage rate measuring unit 36.
The CPU usage rate measuring unit 36 is a part that measures the usage rate of the CPU included in the session control device 30 and detects congestion by detecting that the CPU usage rate exceeds a predetermined value. is there.
The call restriction session control devices 30-1 to 30-n also include a call restriction request unit 34 (not shown) and a CPU usage rate measurement unit 36 (not shown).

  FIGS. 3A and 3B are diagrams showing the relationship between the number of generated calls and the adjustment value in the present embodiment.

FIG. 3A is a graph showing the relationship between the ratio of generated calls and the adjustment value. The horizontal axis shows the ratio x of generated calls with respect to the control amount. The generated call number ratio x is derived by dividing the control amount by the number of generated calls as shown in Equation 2 below.

The vertical axis indicates the adjustment value α to the control amount. The upper limit value of the adjustment value α indicated by the solid line is a value that satisfies the following Expression 3.

As shown in FIG. 3A, the upper limit value of the adjustment value α is clearly larger than 1.0, particularly when the call ratio x is 1.0 to 4.0. Furthermore, the upper limit value of the adjustment value α increases as the generated call ratio x approaches 1.0.
The broken line indicates the adjustment value α = 1.0. The congestion control method of the present embodiment when the adjustment value α = 1.0 is the same congestion control method as in the comparative example.

FIG. 3B is a diagram showing an adjustment value table for obtaining an adjustment value from the ratio of generated calls.
The left column is a numerical column of the generated call number ratio x. The right column is an upper limit value of the adjustment value α corresponding to the generated call ratio x.
In the adjustment value table 28, when the generated call ratio x is 1.1, the adjustment value α is 5.67. When the generated call ratio x is 1.2, the adjustment value α is 3.19.
For example, when the generated call number ratio x is 1.0 to 1.1, the total control amount calculation unit 25 sets the adjustment value α to 5.67, and when the generated call number ratio x is 1.1 to 1.2, By setting the adjustment value α to 3.19, the upper limit value of the adjustment value α can be easily obtained. The lower limit value of the adjustment value α is always 1.0. The range that the adjustment value α can take is between the lower limit value and the upper limit value of the adjustment value α.
When the generated call number ratio x is between 1.1 and 4.0, the range that the adjustment value α can take is any value between 1.0 and 5.67.
When the generated call ratio x is between 1.5 and 4.0, the range that the adjustment value α can take is any value between 1.0 and 1.72.
When the generated call number ratio x is between 2.0 and 4.0, the range that the adjustment value α can take is any value between 1.0 and 1.26.
When the generated call number ratio x is between 1.5 and 2.0, the range that the adjustment value α can take is any value between 1.0 and 1.72.

(Operation of this embodiment)
The congestion control device 20 according to the present embodiment instructs each session control device 30 by paying attention to the fact that, in the call density control method of the comparative example, the number of communicable calls is less than the total control amount. The amount of calls that can be communicated is controlled so as to approach the total amount of control that is a network resource.
The congestion control device 20 is a LAN (Local Area Network) card, a modem, or the like using the allocated control amount as a control instruction by distributing the given control total amount to each session control device 30 when congestion occurs. “Maximum utilization of network resources” is realized by transmitting to each session control device 30 by electromagnetic means of the communication device.

The operation of the congestion control system 1 according to this embodiment will be described with reference to FIGS.
The session control device 30, which is a soft switch, controls the connection request processing unit 32 to connect a call (connection request) transmitted from the user terminal 40 to a target destination.
When congestion occurs, the congestion control device 20 instructs the session control device 30 on the control amount. Upon receiving the control amount instruction, the session control device 30 restricts (call restriction) so that the number of outgoing calls directed to the congestion session control device 30-m does not exceed the control amount.

FIG. 4 is a sequence diagram of the congestion control in the present embodiment.
Here, a basic operation of the congestion control device 20 when congestion occurs in a certain session control device 30-m is described.
When the process is started, the congestion session control device 30-m detects the occurrence of congestion in the sequence Q10.
In sequence Q11, the congestion session control device 30-m notifies the processing unit 21 of the congestion control device 20 of the occurrence of congestion.
In sequence Q12, the congestion control device 20 notifies the network control terminal 10 of the occurrence of congestion by the control instruction unit 26.
In sequence Q13, the network control terminal 10 displays the occurrence of congestion on a display unit (not shown) and notifies the administrator.

In sequence Q14, the network control terminal 10 notifies the processing unit 21 of the congestion control device 20 of the station number designated by the administrator and the total amount of control given to the station number, and starts congestion control.
In sequence Q <b> 15, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 distributes the control total amount to each session control device 30. This total control amount is a call amount that can be communicated to the session control apparatus 30 that accommodates the station number in a predetermined period (cycle).
In sequence Q <b> 16, the processing unit 21 of the congestion control device 20 instructs the session control device 30 on the control content including the station number and the control amount related to the station number by the control instruction unit 26.
In sequence Q17, each session control device 30 counts the amount of calls (traffic amount) to the station number over a predetermined period (cycle), and calls the station number to the control amount. Regulate based on.

In sequence Q <b> 18, each session control device 30 transmits the traffic status that is the amount of calls to the station number in the period to the processing unit 21 of the congestion control device 20.
In sequence Q <b> 19, the processing unit 21 (traffic amount collection unit 23) of the congestion control device 20 totals the call generation amount (traffic amount) in each session control device 30.
In sequence Q <b> 20, the processing unit 21 (traffic amount collection unit 23) of the congestion control device 20 accumulates the traffic amount count result in the DB unit 27.
In sequence Q <b> 21, the processing unit 21 of the congestion control device 20 transmits the traffic amount totaling result to the network control terminal 10 by the control instruction unit 26. The network control terminal 10 displays the traffic amount totaling result on a display unit (not shown).

In sequence Q <b> 22, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 calculates a control amount based on the total control amount and the traffic amount of each session control device 30.
In sequence Q <b> 23, the processing unit 21 of the congestion control device 20 transmits the control content including the station number and the calculated control amount to each session control device 30 by the control instruction unit 26.
In sequence Q24, the processing unit 21 of the congestion control device 20 transmits the control content including the station number and the calculated control amount to the network control terminal 10 by the control instruction unit 26. The network control terminal 10 displays the control content on a display unit (not shown).

The processing unit 21 of the congestion control device 20 according to the present embodiment repeatedly performs the processes of sequences Q18 to Q23 until the congestion is calmed down.
The processing unit 21 of the congestion control device 20 performs proportional distribution (proportional distribution) of the total control amount by the number of calls generated by each session control device 30 in order to ensure fairness of communication in the processing of the sequence Q22. Further, the processing unit 21 obtains an adjustment value α (upper limit value) based on the generated call number ratio x, and multiplies the control amount after proportional distribution by the adjustment value α (upper limit value). The adjustment value α is obtained based on a predetermined table.

FIG. 5 is a flowchart showing the congestion control process in this embodiment.
When the process is started, in step S10, the processing unit 21 of the congestion control device 20 receives the station number of the congestion area and the total control amount related to the station number from the network control terminal 10.
In step S <b> 11, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 distributes the given control total amount evenly to the session control devices 30.
In step S <b> 12, the processing unit 21 of the congestion control device 20 instructs each session control device 30 with the station number and the control amount, which are control contents, by the control instruction unit 26.
In step S13, the processing unit 21 of the congestion control device 20 waits until the next cycle.
In step S <b> 14, the processing unit 21 (traffic amount collection unit 23) of the congestion control device 20 aggregates the number of communication calls and the number of generated calls that are traffic situations from all the session control devices 30.

In steps S15 to S19, the processing unit 21 of the congestion control device 20 repeats the process for each session control device 30.
In step S16, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 calculates the generated call number ratio x (FIG. 3) of the session control device 30.

In step S17, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 calculates the adjustment value α of the session control device 30 from the generated call number ratio x. The adjustment value α is calculated based on the adjustment value table 28.
In step S18, the processing unit 21 (control total amount calculation unit 25) of the congestion control device 20 controls the next cycle of the session control device 30 using the call occurrence rate (number of communication calls and number of generated calls). The amount is distributed and adjusted by the adjustment value α.

  In step S <b> 19, the processing unit 21 of the congestion control device 20 determines whether or not processing has been repeated in all the session control devices 30. If the condition is not satisfied, the processing unit 21 of the congestion control device 20 returns to the process of step S15, and when the process of step S19 ends, returns to the process of step S12.

(Effect of this embodiment)
The present embodiment described above has the following effects (A) and (B).

(A) The congestion control device 20 can calculate an optimal control amount that can best use the total control amount of the network. Thereby, the congestion control apparatus 20 can improve the call communication rate.

(B) The congestion control device 20 obtains the adjustment value α using the adjustment value table 28. As a result, the adjustment value α can be easily obtained without calculating the exponential function shown in Expression 3.

(Modification)
The present invention is not limited to the above embodiment, and can be modified without departing from the spirit of the present invention. For example, the following forms (a) to (e) are available as usage forms and modifications.

(A) The congestion control system 1 has only a soft switch (session control device 30) that performs session control. However, the present invention is not limited to this, and the congestion control system 1 may further include other configurations.

(B) The congestion control device 20 may calculate the adjustment value α (upper limit value) based on the relational expression between the generated call ratio x and the adjustment value α shown in Equation 3. At this time, the total control amount calculation unit 25 further calculates the total number of generated calls by dividing the total number of generated calls by the total control amount to the station number in the congestion area, and subtracts 1.0 from the adjustment value α for adjustment. The adjustment value α may be calculated such that a logarithm is obtained by dividing by the value α, and a value obtained by multiplying the adjustment value α by minus 1.0 is the generated call number ratio x. As a result, the congestion control device 20 can obtain the adjustment value α more precisely, thereby further improving the call communication rate.

(C) The congestion control device 20 selects an arbitrary value between the upper limit value of the adjustment value α and 1.0 (lower limit value), and multiplies the control value of each session control device 30 by the selected value. May be adjusted. Thereby, the congestion control device 20 can suppress the number of communication calls to the predetermined area from exceeding the total control amount of the predetermined area due to the burst of the number of generated calls.

(D) The congestion control device 20 may set a predetermined coefficient (for example, 5.67) as the adjustment value α when the generated call number ratio x in the current cycle is 1.0 or less. As a result, even if the traffic volume of the next period becomes 1.1 due to fluctuations in the traffic volume of each cycle, the generated call volume is prevented from exceeding the total control amount of the congestion session control device 30-m. Is possible.

(E) The congestion control device 20 adds the change amount Δx for each period to the generated call number ratio x in the current period to obtain the maximum value (x + Δx) of the generated call ratio in the next period. Then, the adjustment value α may be calculated. As a result, even if a change in traffic volume occurs in each cycle, it is possible to prevent the generated call volume from exceeding the total control amount of the congestion session control device 30-m.

1, 1A Congestion Control System 10 Network Control Terminal 20, 20A Congestion Control Device 21 Processing Unit 22 Control Code Determining Unit 23 Traffic Volume Collection Unit (Traffic Volume Collection Unit)
24 control instruction information determination unit 25 control total amount calculation unit (control total amount calculation means)
26 Control instruction part (instruction means)
27 DB unit 28 Adjustment value table 30 Session control device 31 Call control unit 32 Connection request processing unit 33 Traffic volume totaling unit 34 Call control unit 35 Resource monitoring unit 36 CPU usage rate measurement unit 40 User terminal 100 Other network x occurrence Call ratio α adjustment value

Claims (6)

Traffic volume collection means for collecting the number of calls generated from each session control device to a predetermined area;
Obtain an adjustment value by the ratio of the number of calls generated by dividing the total number of calls generated by the total control amount to the predetermined area,
Total control amount calculation means for calculating the control amount of the next period of the session control device by allocating the total control amount to the predetermined area to each session control device according to the number of calls generated and multiplying the adjustment value When,
An instruction means for instructing each session control device to regulate a call to the predetermined area by a control amount of the next period;
Equipped with a,
When the call generation ratio is any of 1.1 to 4.0, the adjustment value is any of 1.0 to 5.67.
The congestion control apparatus characterized by the above-mentioned. Traffic volume collection means for collecting the number of calls generated from each session control device to a predetermined area;
Obtain an adjustment value by the ratio of the number of calls generated by dividing the total number of calls generated by the total control amount to the predetermined area,
Total control amount calculation means for calculating the control amount of the next period of the session control device by allocating the total control amount to the predetermined area to each session control device according to the number of calls generated and multiplying the adjustment value When,
An instruction means for instructing each session control device to regulate a call to the predetermined area by a control amount of the next period;
Equipped with a,
The control total amount calculation means further includes
The total number of generated calls is divided by the total control amount to calculate the ratio of generated calls, 1.0 is subtracted from the adjustment value and divided by the adjustment value to obtain a logarithm, and the adjustment value And the adjustment value such that a value obtained by multiplying minus 1.0 becomes the ratio of the number of calls generated,
The congestion control apparatus characterized by the above-mentioned. Storage means for storing an adjustment value table indicating a relationship between the generated call ratio and the adjustment value;
The total control amount calculation means further acquires the adjustment value from the generated call number ratio based on the adjustment value table.
The congestion control apparatus according to claim 1 , wherein the congestion control apparatus is configured as described above. A call restriction means for restricting outgoing calls to the predetermined area with the instructed control amount;
Traffic volume totaling means for counting and notifying the number of generated calls;
A session control device,
And the congestion control device according to any one of claims 1 to 3 ,
A congestion control system comprising: A traffic volume collecting step for collecting the number of calls generated from each session control device to a predetermined area;
An adjustment value calculating step for obtaining an adjustment value by a ratio of the number of generated calls obtained by dividing the total number of generated calls by the total control amount to the predetermined area;
Total control amount calculation step of calculating the control amount of the next period of the session control device by allocating the total control amount to the predetermined area to each session control device according to the number of calls generated and multiplying the adjustment value When,
An instruction step for instructing each session control device to regulate a call to the predetermined area by a control amount of the next period;
The execution,
When the call generation ratio is any of 1.1 to 4.0, the adjustment value is any of 1.0 to 5.67.
A congestion control method characterized by the above. A traffic volume collecting step for collecting the number of calls generated from each session control device to a predetermined area;
An adjustment value calculating step for obtaining an adjustment value by a ratio of the number of generated calls obtained by dividing the total number of generated calls by the total control amount to the predetermined area;
Total control amount calculation step of calculating the control amount of the next period of the session control device by allocating the total control amount to the predetermined area to each session control device according to the number of calls generated and multiplying the adjustment value When,
An instruction step for instructing each session control device to regulate a call to the predetermined area by a control amount of the next period;
The execution,
In the total control amount calculating step,
The total number of generated calls is divided by the total control amount to calculate the ratio of generated calls, 1.0 is subtracted from the adjustment value and divided by the adjustment value to obtain a logarithm, and the adjustment value And the adjustment value such that a value obtained by multiplying minus 1.0 becomes the ratio of the number of calls generated,
A congestion control method characterized by the above.

Images