JPH0414822B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a call control system in an exchange.

There is a natural limit to the number of calls that can be processed in a switch. If this is called the allowable number of calls to be accepted, if calls exceed the allowable number of calls, the exchange will be overloaded, leading to an increase in the number of queues held in the system and an increase in the number of assets acquired.
Generates overhead. As a result, the system throughput is lower than usual.

Therefore, call control to deal with such overload is required. Generally, static call control methods and dynamic call control methods are known to perform this call control. The former static call control method measures the processor usage rate at regular time intervals, and when this measured value exceeds a predetermined upper limit, it starts restricting calls, and this restriction reduces the processor usage rate. When the measured value falls below a predetermined lower limit, the restriction is lifted. On the other hand, the latter dynamic call control method monitors the number of calls made at fixed time intervals, the number of accepted calls sent to exchange processing, and the usage rate of the processor, and determines how many more calls can be made. The number of calls that can be accepted is judged and determined one after another, and the exchange is always operated at the limit of its processing capacity.

Comparing the above two types of call control methods, the latter method is far superior in effective use of system resources. This is because, according to the former method, the processor usage rate (which is approximately proportional to the number of accepted calls) fluctuates in large waves between the upper limit and the lower limit. This is because system resources are left unused every step of the way. Therefore, the system of the present invention to be described below is constructed based on a dynamic call control system that is excellent in effectively utilizing resources.

[Conventional technology]

FIG. 3 is a block diagram showing an example of a switching system configured based on a conventional call control method.
This is based on the dynamic call control described above.
Note that this dynamic call control, for example,
Processor Overload Control for SPC
Electrical as “Smitching Systems”
Communication・Volume 55, Number 1, 1980
It is described in. In Figure 3, inter-office line 1
1 and subscriber line 12 are received by call detection circuits 13 and 14, respectively. Initial call signals OC1 and OC2 are applied to the call control unit 15 in the exchange system. The call control unit 15 determines whether to accept or restrict these calls, and when accepting the call, drives the call processing unit 16 to perform normal switching operations for the call. On the other hand, if the call has to be restricted due to overload, the call restriction section 17 is activated to return a busy tone or the like to the call. The present invention provides the above-mentioned call control section 15.
This determination by the call control unit 15 is performed in cooperation with the allowable number of accepted calls determining unit 18 and the number of accepted calls counting unit 19 . The permissible accepted number of calls determination unit 18 comprehensively takes into account the number of accepted calls, the number of outgoing calls, the usage rate of a processor CPR (Call Processor), etc. at fixed time intervals (for example, every second), and determines the number of acceptable accepted calls one after another. Number of calls
Configure NI. On the one hand, the allowable number of accepted calls NI is set in the sequentially accepted call counting section 19, but on the other hand, it is subtracted by the decrement signal D output every time a call is accepted. That is, each time one call is accepted, the number of calls that can be accepted is reduced by one. If the count value of the outgoing call acceptance call counting section 19 reaches zero, the outgoing call can no longer be accepted, so the outgoing call restriction signal R is output to the outgoing call control section 15. The control section 17 is instructed to be driven.

[Problem that the invention seeks to solve]

In the call control method explained in FIG. 3, since each control information is essentially transmitted instantaneously, it is meaningless unless the call control section 15 and the allowable number of accepted calls determination section 18 operate in real time. In other words,
Information such as the number of calls accepted, the number of calls made, and the CPR usage rate must be collected in real time, and instructions for restricting calls must also be issued in real time. However, for example, each line group (11, 1 in Figure 3)
2) LPR with call control unit 15 provided for each
Such a high level of real-time performance cannot be guaranteed in a switching system configured so that a line processor (Line Proessor) and a CPR having a call acceptance/call counting unit exchange information via a communication line. This is because information cannot be transmitted instantaneously between LPR and CPR because it is performed according to a certain protocol.

In exchanges that cannot maintain a high level of real-time performance, the decision made by the allowable number of accepted calls decision unit 18 is always delayed, and the regulation of outgoing calls is delayed, so when a sudden overload occurs, However, there is a problem that this problem cannot be dealt with quickly, resulting in overhead.

Further, as a call regulation method, a method may be considered in which all calls are not regulated, and, for example, some priority subscribers are processed as usual and only general subscribers are regulated. In this case, the conventional system does not take into account the fact that more calls than the predetermined number of permissible calls will be accepted, so the number of calls made by the restricted priority subscriber will be accepted in excess of the permissible number. Therefore, when such a regulation method is used, there is a problem that good control cannot be achieved.

[Means for solving problems]

The present invention provides a call control method in an exchange that solves the above problems, and the number of outgoing calls counted at each fixed time interval exceeds the number of allowable accepted calls set within that time interval. Even if the number of calls exceeded, the call can still be accepted, and the number of calls that can be accepted is set by subtracting the number of calls that are allowed to be accepted within the next time interval by the number of calls that exceeded the number of calls. , if the number of calls counted at a given time interval is less than the allowable number of accepted calls set within the time interval, at least the number of calls The number of calls that can be accepted is set by increasing the number of calls that can be accepted within the next time interval by the number of calls that can be accepted. It is designed to perform regulatory control.

[Effect]

Even if the number of outgoing calls exceeds the allowable number of accepted calls, the outgoing calls may be accepted, so that there is no need to maintain real-time performance. Then, in the next time interval, the allowable number of calls that can be accepted is subtracted by the number of calls that exceeded the number of calls, and the actual number of calls that can be accepted is set. This type of call control is achieved due to the fact that each call does not complete its switching process instantaneously within each time interval, but actually completes its switching process after the next time interval. This is due to the fact that we focused on In this way, even if calls exceeding the above-mentioned allowable number of calls are accepted, if calls are restricted until the call switching process is completed, the situation will not exceed the allowable number of accepted calls on average. do not have.

〔Example〕

FIG. 1 is a block diagram showing an example of a switching system for implementing the system according to the present invention. Note that the same reference numbers or symbols are given to the same components throughout the drawings. Therefore, blocks 21 to 23 in FIG. 1 become new components, but among these, block 23 most characterizes the present invention. In the present invention, instead of setting the allowable accepted call number NI from the allowable accepted call number determination unit 18 as it is in the outgoing accepted call number counting unit 19, the accepted call number modification unit 23 modifies the accepted call number NI so that it can be accepted. It is assumed that the number MI is set in the number of outgoing and accepted calls counter 19.

It is the same as in the prior art that the count value of the call acceptance number counting section 19 is subtracted by the decrementer signal D output every time a call is accepted. Further, when the calculated value reaches a predetermined value (zero) through this subtraction, a call restriction flag F is set via the call restriction instructing section 21 to instruct the call restriction section 17 to be driven. This is almost the same as before. However, the following points differ from the conventional method. In the past, call restriction was started as soon as the count value of the call acceptance point counting unit 19 became zero, but in the present invention, calls can be accepted even if the number of calls exceeds the allowable number of accepted calls. is possible. Here, the excessive count value in the outgoing and accepted calls counting section 19 is calculated by the restricted accepted calls counting section 22 as the number of calls that were accepted despite being restricted. This count value PI
Since (PI > 0) is applied to the - input of the number of accepted calls modification section 23, the number of acceptable calls NI therein is modified to (NI - PI), which is the number of acceptable calls MI (= NI −PI). As a result, in the next subsequent time interval, MI (MI<NI) is reset in the outgoing call acceptance number counter 19 instead of NI. In this case, the call processing unit 16 is overloaded by the count value PI, but the call exchange process corresponding to the count value PI is not completed instantaneously, but is completed after a certain period of time. The number of calls accepted at MI (=
If the number of calls is reduced to NI - PI), the number of accepted calls will be averaged over the long term and there will be no overload.

Conversely, when the number of outgoing calls is less than the allowable number of accepted calls, the system resources can be maximized by increasing the number of acceptable calls MI by at least the number of outgoing calls that has fallen below. For this reason,
The received call number correction unit 2 receives the surplus value QI until the counted value of the outgoing and accepted call number counting unit 19 overflows.
3 to the + input, modify NI to (NI+QI), and set the number of acceptable calls MI (=NI+QI).

FIG. 2 is a block diagram showing a better embodiment of the configuration of FIG. 1. It is assumed that the outgoing/accepted call counting section 31 (corresponding to 19 in FIG. 1) in this figure can take a negative value depending on the decrement signal. That is, the positive/negative display signal P becomes + or - depending on the positive/negative of the count value of the counting section 31. When the signal P is +, the call is accepted; when it is -, the call restriction instruction unit 21 is driven to set the call restriction flag F, and the call restriction unit 17 initiates the call. Make regulations. In this case, the number of accepted calls correction unit 32 (corresponding to 23 in FIG. is added to the count value TI, and preset from the preset input of the external counting section 31 via line L1.

In this way, the outgoing/accepted call number counting section 31 integrates not the absolute value of the number of calls but the variation in the number of calls. Then, depending on the state of the call, it is expected that the count value of the call acceptance call counting section 31 will continue to increase linearly with the passage of time. Therefore, an initialization section 34 is provided to periodically (for example, 10
every second), initializes the outgoing call acceptance call counting unit 31,
Return the count value to zero. This takes place via line L2. By initializing in this manner, it is possible to prevent the count value from continuing to increase and exceeding the actual allowable number of accepted calls.

It is preferable that the above initialization be performed selectively only when the count value of the counting section 31 is positive (the polarity display signal P is +). If it is initialized when P is negative (-) (when calling is restricted), it will appear that
This is because the number of calls that can be accepted increases.
For this reason, the polarity display signal P is also input to the initialization section 34 through the line L3, and initialization is executed only when P is +.

〔Effect of the invention〕

As explained above, according to the present invention, a switching system in which a high level of real-time performance is not guaranteed for the number of accepted calls from the allowable number of accepted calls determining unit 18,
A switching system is realized in which a conventional dynamic call control method can be applied even when a method is applied that allows priority subscribers to make calls even under restrictions. Furthermore, system resources can be used more effectively than in the past.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a switching system for implementing the method based on the present invention, and FIG. 2 is a block diagram showing a better embodiment of the configuration of FIG. 1.
FIG. 3 is a block diagram showing an example of a switching system constructed based on a conventional call control system. 15...Call control unit, 18...Permissible accepted call number determination unit, 19, 31... Outgoing accepted call number counting unit,
23, 32...Accepted call number modification unit, 34...Initialization unit.

Claims (1)

[Claims] 1. Based on the number of outgoing calls and the number of outgoing and accepted calls counted at each fixed time interval, and the usage rate of the processor measured at each fixed time interval, In a switching system, the switching equipment includes an allowable number of accepted calls determining unit that sets an acceptable number of accepted calls for each time interval, and a call control unit that determines whether or not to accept a call in accordance with the set number of acceptable accepted calls. , an accepted call number modification unit inserted between the allowable accepted call number determination unit and the call origination control unit; On the other hand, the accepted call number correction unit accepts the call as is, and the number of accepted calls is adjusted to the number of accepted calls set within the next predetermined time interval. The number of calls that can be accepted is set by reducing the number of calls;
When the number of accepted calls falls below the allowable number of accepted calls, the number of accepted calls set within the subsequent certain time interval is increased by at least the number of calls that has fallen below the number of accepted calls, and the number of accepted calls is increased. A call control method in an exchange, characterized in that a number of possible calls is set, and the call control unit performs regulation control of the call acceptance based on the number of acceptable calls from the number of accepted calls modification unit. 2. The number of calls that can be accepted is counted by a number of outgoing and accepted calls counting section, and the number of outgoing and accepted calls is counted by the number of outgoing and accepted calls counting section at the beginning of the certain time interval. preset the sum of the final counted value and the allowable number of accepted calls, while the counted value is decremented by 1 each time the outgoing call is accepted;
Call control in the exchange according to claim 1, wherein if the count value is positive, the call is accepted, and if the count value is negative, the call is restricted from being accepted. method. 3. The call control system in an exchange according to claim 2, wherein the count value of the call acceptance call counting section is periodically initialized to zero. 4. The call control system in an exchange according to claim 3, wherein the initialization is performed only when the count value of the call reception/call counting section is positive.