JP2579946B2 - Congestion control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a congestion control method for an abnormal call or the like in an electronic exchange of a stored program control method.

(Prior Art) As shown in FIG. 3, an electronic exchange of a storage program system is provided with a signal processing unit 1, a call control unit 2, a failure diagnosis processing unit 3, a schedule management unit 4, and the like. The signal processing unit 1 includes a central office interface 1a, a standard telephone interface 1b, and a key telephone interface 1n as shown in FIG.
A state change of a subscriber loop, control information (such as a call signal) from a subscriber terminal, and an SS / SR signal from a trunk circuit are input via 1a, 1b, to 1n. After each of these input control information is subjected to predetermined preprocessing, it is converted into common signal information, stored in the FIFO memory 6 in order, and sequentially subjected to call processing.

The signal number counter 7 counts the number of signals stored in the FIFO memory 6 and counts up the value each time a signal of the FIFO memory 6 is written.
Each time a signal is read from the memory 6 to the call control unit 2, the value is counted down. The value of the signal number counter 7 indicates the number of signals stored in the FIFO memory 6 and still not read out by the call control unit 2.

Then, the call control unit 2 sequentially reads the signals from the FIFO memory 6 of the signal processing unit 1 through the path a in the signal reading unit 2a, and performs switching control, terminal control, etc. according to the signal read from the signal processing unit 1. Is performed.

The failure diagnosis processing unit 3 performs various state diagnoses including a congestion process, failure detection, and the like. Specifically, for example, the congestion control unit 3a provided in the failure diagnosis processing unit 3
The signal number counter 7 of the signal processing unit 1 is periodically scanned through a path b, and the number of signals remaining unprocessed in the FIFO memory 6 is obtained from the value of the signal number counter 7. . When the number of signals exceeds a predetermined threshold value, it is determined that the signal is in a congestion state, and a countermeasure for failure is activated. This trouble countermeasure is performed by, for example, prohibiting the signal processing unit 1 from accepting a new call.

The schedule management unit 4 adjusts and manages differences in processing cycles in a plurality of processing programs that control the execution of these units, and controls the progress thereof, for example, by executing them in order or by performing periodic task control by activating a timer. Things.

By the way, in the conventional electronic exchange having such a configuration, the period of congestion detection is generally made longer than the period of signal reading by the call control unit 2, thereby reducing the CPU load for congestion detection. . However, if such a congestion detection cycle is set, the response to a sudden increase in traffic is delayed, and there is a problem that many congested signals are held when congestion is detected. That is, as described above, the congestion detection is performed by checking the value of the signal number counter 7 every predetermined period T and determining whether the value exceeds the congestion detection level (threshold). For this reason, as shown in FIG. 5, if traffic increases rapidly during the period of the detection period T, a situation occurs in which many signals are already stored in the FIFO memory 6 at the time of the next detection of congestion. As a result, there arises a problem that the FIFO memory 6 embraces many signals without processing.

In addition, since the call control and the congestion control operate independently as described above, the call control unit 2 rejects the call signal already stored in the FIFO memory 6 among the abnormal call signals that are the main cause of the congestion. A problem arises that it cannot be done.

(Problems to be Solved by the Invention) As described above, in the related art, since the call control and the congestion control are executed independently, it is not possible to immediately detect the congestion when it occurs, At the time when the congestion detection is executed, a trouble such as a large number of staying signals has already occurred.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a congestion control method in an electronic exchange which can quickly detect occurrence of a congestion state and take effective congestion countermeasure processing.

[Configuration of the Invention] (Means for Solving the Problems) The present invention detects the presence or absence of a control signal from a subscriber terminal,
The detected control signals are sequentially stored in the signal storage unit, and the control signals stored in the signal storage unit are sequentially read to perform call control, and the number of the control signals of the exchange is determined based on the number of control signals remaining in the signal storage unit. In an electronic exchange of a storage program control system for judging a high load state and detecting congestion, a call control unit performs congestion detection when reading a control signal from a signal storage unit. Call control for the control signal read from the controller, and in a congestion state, notifies the reception of new call information to the signal storage unit and prohibits the reception of the control signal read from the signal storage unit. It is characterized by the following.

(Operation) According to the present invention, when the call control unit sequentially reads out the control signals from the subscriber terminals sequentially stored in the signal storage unit and executes the call control unit, the congestion detection is sequentially performed. Therefore, when the number of control signals stored in the signal storage unit increases and a congestion state occurs, the occurrence of the congestion state is promptly detected in synchronization with signal reading by the call control unit. Since reception of new call information is prohibited and storage of a new signal in the signal storage unit is prohibited, an abnormal number of signals are not stored in the signal storage unit.

In other words, the congestion detection is performed simultaneously when the control signal for performing the call processing is read from the signal storage unit. Therefore, the period of the congestion detection is set short, the occurrence of the congestion state is quickly detected, and the congestion countermeasure processing is performed effectively. It is possible to start.

As a result, an extremely large effect can be obtained in practical use, for example, an abnormally large number of control signals are held in the signal storage unit, and problems such as inability to cope with the control signals are not caused.

In addition, the congestion detection is performed not by the failure diagnosis processing unit but by the call control unit capable of high-speed processing, so that the load on the failure diagnosis processing unit can be reduced, thereby making the switching system more efficient as a whole. Processing becomes possible.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the processing concept of the embodiment system. 1 is a signal processing unit in an electronic exchange of a stored program control system, 2 is a call control unit, 3 is a failure diagnosis processing unit, and 4 is a schedule management unit. These are realized by software, and are basically configured in the same manner as the conventional electronic exchange shown in FIG.

Here, the processing control method of the present exchange is characterized in that the call control unit 2 is provided with the signal readout unit 2a, and the congestion control unit 3a conventionally provided in the fault diagnosis processing unit 3 is characterized by The point is that the call control unit 2 is provided.
The signal reading unit 2a of the call control unit 2 sequentially reads the control signals stored in the FIFO memory 6 of the signal processing unit 1 via the path a via a path a, and simultaneously reads the congestion control unit provided in the call control unit 2. 3a, the signal number counter 7 of the signal processing unit 1 is simultaneously scanned via the path b to detect congestion.

The path c provided between the failure diagnosis processing unit 3 and the call control unit 2 is used to provide the information to that effect to the failure diagnosis processing unit 3 when the congestion is detected by the call control unit 2. belongs to.

FIG. 2 shows a flow of a processing procedure in the electronic exchange configured as described above, and a characteristic congestion control method of the present invention will be described with reference to FIG.

The call control unit 2 reads the signals stored in the FIFO memory 6 of the signal processing unit 1 sequentially through the path a,
First, the count value of the signal counter 7 of the signal processing unit 1 is read via the path b (step A), and the count value is determined each time (step B).

This determination is made as to whether or not a signal remains in the FIFO memory 6 (whether or not the count value is “0”). If there is a signal, the number of signals (count value) is equal to or more than a predetermined number. This is done by checking whether or not there is any.

Specifically, for example, when the count value N of the signal counter 7 is (0), it is determined that there is no signal to be subjected to call processing. That is, it is determined that there is no signal to be subjected to call processing in the FIFO memory 6. In this case, the reading of the count value of the signal number counter 7 shown in step A and the determination of the count value N shown in step B are periodically and repeatedly executed.

Therefore, in this case, the call control unit 2 repeatedly executes the above-described read processing procedure until the signal to be processed is stored in the signal processing unit 1.

On the other hand, when a new call processing request is generated, the control signal is stored in the FIFO memory 6 and the signal counter 7 is counted up. As a result, it is determined that the count value is not “0” by the above determination process (step B), and it is detected that the signal to be processed exists in the FIFO memory 6.

In this case, the count value N is first set to the predetermined value K.
It is determined whether or not this is the case. The determination as to whether or not the count value N has exceeded the predetermined value K is to determine whether or not a congestion state has occurred. When the count value N has exceeded the predetermined value K, it is determined that the congestion state has occurred. It is determined to have occurred.

Here, when a new call processing request is issued from the above-mentioned standby state, the call does not immediately fall into the congestion state. Therefore, it is generally confirmed that the count value N does not exceed the predetermined value K. That is, the control information stored in the FIFO memory 6 is read out after confirming that the state is not the congestion state,
The call control unit 2 executes a call process on the signal read from the signal processing unit 1 (step C). By executing the call processing, the corresponding control information stored in the FIFO memory 6 is deleted and the signal number counter 7 is counted down.

Then, when the call processing is completed, the call control unit 2 repeatedly executes the processing from step A described above to perform the reading processing for the next signal.

By the way, the number of input signals to the signal processing unit 1 increases,
When the number of signals stored in the FO memory 6 increases, the count value N of the signal number counter 7 increases accordingly. When the count value N exceeds the above-mentioned predetermined value K, the occurrence of a congestion state is detected by the determination processing shown in step B described above.

Then, the call control unit 2 first notifies the fault diagnosis processing unit 3 that congestion has occurred (step D), and starts the congestion countermeasure processing. Further, the occurrence of this congestion state is notified to the signal processing unit 1 (step E), and an instruction is given to limit the reception of a new input signal.

As a result, acceptance of a new signal by the signal processing unit 1 is prohibited, and storage of the signal in the FIFO memory 6 is stopped. Therefore, after the congestion state is detected, no new control signal is stored in the FIFO memory 6. After such congestion detection processing is performed, the above-described step C
Is performed.

If the occurrence of the congestion state is repeatedly detected in the determination processing, it is determined that the countermeasure processing for the congestion state has already been started. In this case, only the call processing for the signal read from the signal processing unit 1 at that time is executed (step C).

As described above, in the present system, when a signal is read from the signal processing unit 1 to the call control unit 2, the number of signals stored in the FIFO memory 6 of the signal processing unit 1 is checked each time, and the system is in a congestion state. No will be determined. That is, congestion detection is sequentially performed as part of the call processing. Therefore, even if there is a sudden signal input within a short time,
As a result, the congestion state can be quickly detected.
Since the input of a new signal is prohibited, it is possible to prevent a problem that an abnormally large number of signals are stored in the FIFO memory 6 beforehand.

Further, since the above-described call processing is usually performed in a time period of about several tens of msec, the period of congestion detection can be sufficiently shortened. Therefore, the congestion can be detected before many unprocessed control signals stay in the FIFO memory 6. Therefore, it is possible to easily and efficiently take measures when congestion is detected.

Note that the present invention is not limited to the above-described embodiment. For example, the threshold for determining the number of signals to be determined to be in the congestion state may be determined according to the specifications, and may be variously modified without departing from the gist of the present invention.

[Effects of the Invention] As described above, according to the present invention, when signals input to a signal processing unit are sequentially read out to a call control unit, determination of a congestion state is performed based on the number of signals stored in the signal processing unit. Is performed each time. As a result, practically significant effects such as shortening the period of the congestion detection, quickly detecting the congestion state, and effectively taking a countermeasure against the congestion can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an electronic exchange to which an embodiment of the present invention is applied and the concept of its processing, FIG. 2 is a diagram showing a flow of processing procedures in the embodiment of the present invention, and FIG. FIG. 4 is a diagram illustrating a processing concept of the electronic exchange, FIG. 4 is a diagram illustrating a configuration example of a signal processing unit, and FIG. 5 is a diagram illustrating the number of signals stored in the signal processing unit and a concept of congestion detection. DESCRIPTION OF SYMBOLS 1 ... Signal processing part, 2 ... Call control part, 2a ... Signal read-out part, 3
... Failure diagnosis processing unit, 3a congestion control unit, 4 schedule management unit, 6 FIFO memory, 7 signal counter.

Claims (1)

(57) [Claims] 1. A signal processing unit for detecting the presence or absence of a control signal from a subscriber terminal and sequentially storing the detected control signals in a signal storage unit, and sequentially reading out the control signals stored in the signal storage unit. In an electronic exchange of a storage program control system comprising a call control unit for performing call control and a failure diagnosis processing unit for performing a predetermined failure countermeasure process when a failure is detected, the call control unit includes: A signal reading unit for sequentially reading a control signal from the unit in a cycle corresponding to the call processing; and each time the control signal is read by the signal reading unit,
The high load state of the exchange is determined from the number of control signals remaining in the signal storage unit, and when the high load state is determined, the information to that effect is notified to the failure diagnosis processing unit and the high load state is set. In addition to performing the corresponding failure countermeasure processing,
A congestion control unit that also notifies the signal processing unit of information indicating that the load has been determined to be high and prohibits storage of a new control signal in the signal storage unit; and a control signal read by the signal reading unit. A congestion control system comprising: a call processing unit that performs call processing in response to the call.