JPH10210512A - Trunk selection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve the CPU load of trunk control by an exchange in a call connection processing by selecting immediately an idle trunk among office line trunk groups in multi-line connection in the case of call connection control. SOLUTION: Trunk information tables J of idle trunks in an office line trunk group are linked while placing an idle trunk list header H to a top of the list structure. After trunk reception processing, the idle trunk list is referenced and a trunk number is acquired from the trunk information tables J linked to the head of the list and an office line trunk corresponding to the acquired trunk number is used for an outgoing trunk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exchange for selecting a free trunk from a multiline-connected office trunk group and performing a calling process using the selected free trunk when controlling call connection. It relates to a trunk selection method.

[0002]

2. Description of the Related Art An exchange has a plurality of subscriber line trunks and a plurality of central office trunks. The subscriber line trunk connects a CPU in the exchange and a subscriber terminal such as a subscriber telephone via a subscriber line. The central office trunk connects to another exchange via a trunk line. When a call is generated, for example, by making a call from a subscriber telephone, the subscriber line trunk of the exchange performs termination processing. After this, the CPU inside the exchange
Performs a route selection process to secure a route requested to be connected, and selects an outgoing trunk.

In the case where the outgoing trunk is a central office trunk connecting to another exchange via a trunk line, and the trunk line with the exchange is a multiple connection by a plurality of central office trunks, An empty trunk that is not in use at that time is selected from the office trunk group that realizes multi-line connection, and the selected empty trunk is set as an outgoing trunk. This outgoing trunk performs outgoing call processing to establish a connection with another exchange.

If all the trunks in the multiline-connected trunk trunk group are in use and an empty trunk cannot be selected, that is, if the outgoing trunk cannot be determined, the CPU in the exchange will Reject the call connection and perform trunk busy processing on the incoming trunk. The selection of an empty trunk from the multi-line connected trunk trunk group is performed not only when the call arrives from the subscriber line but also when the call arrives at the trunk via the trunk from another exchange. Is performed in a similar manner.

Conventionally, in a trunk selection method in this type of exchange, a call termination process is performed at an incoming trunk, and a search for an empty trunk in an office line trunk group is performed at the stage of selecting an outgoing trunk through a route selection process. Had been For example, Japanese Patent Publication No. 1-20825 discloses that the use status of all the trunks in the trunk trunk group is recorded in a table and monitored, and when selecting an outgoing trunk, the table is referred to to identify an empty trunk. The method to be selected is described. Also, Japanese Patent Application Laid-Open No. 3-28395
Japanese Patent Application Laid-Open No. 6-32064 describes a method of recording the use status of a trunk in a communication path memory in an exchange and selecting an empty trunk by referring to information in the memory. Further, Japanese Patent Application Laid-Open No. 2-41094 describes a method in which the traffic volume of each trunk is recorded in a memory together with the usage status of the trunk, and the trunk is selected in the order of vacancy and traffic volume.

As described above, in the related art, the selection of an empty trunk from a multiline-connected office trunk group involves the use of an office trunk in the trunk group recorded in a memory constituting the exchange. A method is used in which an empty trunk is searched for one by one, and if there is an empty trunk, it is immediately selected and captured. However, in any of the methods, the search for an empty trunk in the line trunk group is performed after the call arrives at the trunk of the exchange.

[0007]

A problem of the conventional trunk selection system in the exchange is that it takes time to select and capture an empty trunk from the local trunk group. The reason is that, after a call arrives at the exchange, a line trunk group to be connected is determined through a route selection process,
Further, the use status of the office line trunk belonging to the office line trunk group is examined one by one to search for an empty trunk. This problem becomes more remarkable as the number of office trunks constituting the office trunk group increases and the traffic volume accommodated by the office trunk increases. Moreover, the hold time of the call that seizes the transmission trunk is completely random, the existence of empty trunks in the local trunk group is not uniform in time, and even if the usage of each trunk is monitored in memory, When actually selecting an empty trunk, the usage status of each trunk in the memory must be examined one by one by judging whether the trunk is in use or empty. However, if the process of searching for an empty trunk every time a call arrives is performed by all the exchanges on the path to which the call is connected, the time required for establishing the requested call will be long. Also, if the number of trunks to be searched for an empty trunk increases, the occupation time of the CPU for one call in each exchange becomes longer.
At the same time, connection processing for incoming calls is made redundant.

The present invention has been made to solve such a problem, and an object of the present invention is to select an empty trunk from a multiline-connected office trunk group when controlling call connection. CPU for trunk control of the exchange in call connection processing
It is an object of the present invention to provide a trunk selection method in an exchange which can reduce the load, thereby improving the call connection processing capacity of the exchange per unit time and consequently improving the efficiency of use of the line.

[0009]

In order to achieve the above object, a first invention (an invention according to claim 1) provides a method for controlling connection of a call from among multi-line-connected office trunk groups. In an exchange which selects an empty trunk and performs a calling process using the selected empty trunk, an empty trunk list means for indicating an empty trunk in the line trunk group is provided, and the empty trunk list means is provided for controlling call connection. Browse and select an empty trunk,
The calling process is performed using the selected empty trunk. According to the present invention, the transmission trunk is immediately selected with reference to the empty trunk list means.

In the second invention (the invention according to claim 2), at the time of call connection control, an empty trunk is selected from a multiline-connected office line trunk group, and a call is originated using the selected empty trunk. In the exchange performing the processing, a list structure of an empty trunk list is created by linking the trunk information tables of the empty trunks in the line trunk group, and at the time of call connection control, an empty trunk is selected by referring to the empty trunk list; The calling process is performed using the selected empty trunk. According to the present invention, the transmission trunk is immediately selected with reference to the empty trunk list.

According to a third invention (an invention according to claim 3), at the time of call connection control, an empty trunk is selected from a multiline-connected office line trunk group, and a call is originated using the selected empty trunk. In the exchange performing the processing, a list structure of an empty trunk list is created by linking the trunk information tables of the empty trunks in the line trunk group, and at the time of call connection control, an empty trunk is selected by referring to the empty trunk list; The outgoing call processing is performed using the selected free trunk, while the trunk information table of the selected free trunk is separated from the list structure of the free trunk list, and the trunk information table of the separated free trunk is released from the call connection. Later, it is added to the list structure of the free trunk list. According to the present invention, the transmission trunk is immediately selected with reference to the empty trunk list. In this case, the trunk information table of the selected free trunk is separated from the list structure of the free trunk list. The trunk information table of the separated empty trunk is added to the list structure of the empty trunk list after the call is released.

The fourth invention (the invention according to claim 4) is the first invention.
In the third aspect of the present invention, if no empty trunk is listed in the call connection control, it is determined that all the trunks in the multiline-connected trunk transgroup are in use, and the trunk on which the call arrived is determined. Requesting a busy process. According to the invention,
In the connection control of the call, if there is no empty trunk in the list, a busy process is immediately requested for the trunk on which the call has arrived.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. FIG. 1 is a diagram showing a main part of a communication system to which the present invention is applied. In the figure, 1 (1
-1 to 1-n) are subscriber telephones, 2 is an exchange, and 2 'is another exchange. The exchange 2 is an electronic exchange of a storage program control type, and the CPU 3 reads and executes a control program stored in the memory 4 in advance to perform control. Information necessary for control is stored and held in the memory 4. The memory 4 also holds a route selection information table necessary for the route selection process.

Reference numeral 5 (5-1 to 5-n) denotes a subscriber line trunk associated with the exchange 2. The subscriber line trunk 5 (5-
1 to 5-n) are connected to subscriber telephones 1 (1-1 to 1-n) via subscriber lines L (L1 to Ln). 6 (6
-1 to 6-m) are office trunks. Office line trunk 6
(6-1 to 6-m) are connected to another group of exchanges including the exchange 2 '. The lines connected to the office line trunks 6-1 to 6-m serve as trunk lines for connecting calls to other exchange groups including the exchange 2 'and to exchanges connected to extensions of those exchange groups. ing.

In FIG. 1, the trunk line between the exchange 2 and the exchange 2 'has a multi-line connection for mutually connecting a plurality of central office trunks. That is, the office trunks 6-2, 6-3, 6-4, 6-5 of the exchange 2 and the office trunks 6'-2, 6'-3, 6'-4, 6-2 of the exchange 2 '.
6′-5 are connected to each other, and
-5 form one multi-line connected central office trunk group. In this case, a call for selecting a route to be connected from the exchange 2 to the exchange 2 'is sent to the office trunk 6-.
The connection to the exchange 2 'is established by using the office line trunk which is vacant at the time of connection among 2-6-5.

In the exchange 2, at any one time, the CPU 3 always recognizes which line trunk in the line trunk group connected by multi-line is free through the empty trunk list held in the memory 4. . FIG.
FIGS. 4A to 4D are diagrams illustrating the transition of the list structure of the empty trunk list held in the memory 4;

In FIG. 2A, J2, J3, J4,
J5 is a trunk information table of the office line trunks 6-2, 6-3, 6-4, and 6-5, each of which is recorded in the memory 4 as one information table. The trunk information table J records a trunk number, trunk information, a list pointer to the next table, and the like (see FIG. 3). The trunk information table J is dynamically generated under the control of the CPU 3, and is linked using the head memory address of each table as a pointer.

FIG. 2A shows a trunk information table J.
2, a list structure linked in the order of J3, J4, J5 is shown, and an empty trunk list header H is provided at the head of the list structure. In the empty trunk list header H, an address pointer to the trunk information table J at the head of the list is recorded, and is recorded from a fixed memory address so that the CPU 3 can immediately refer to it. When the operation of the exchange 2 is started, all the office trunks 6
Is empty, so that the line trunks 6-2, 6-3,
6-4, 6-5 trunk information tables J2, J3, J
4 and J5 are linked as shown in FIG.

Next, the operation of this embodiment will be described with reference to the flowcharts of FIGS. 1, 2, 3 and 4. [Connection of Call] First, a call is generated by making a call from the subscriber telephone set 1-1, and a request is made to connect a communication path from the exchange 2 to the exchange 2 '. Subscriber telephone 1-
1 is accepted by the subscriber line trunk 5-1 of the exchange 2, and a trunk terminating process is performed (step A1 shown in FIG. 4).

After the trunk termination processing, the CPU 3 analyzes the telephone number received by the subscriber line trunk 5-1 (step A2), and executes a path selection processing based on the path selection information table recorded in the memory 4. (Step A3), an office trunk group for connecting a call to a route corresponding to the requested telephone number is determined (Step A4). When a line trunk group composed of the line trunks 6-2, 6-3, 6-4, and 6-5 is selected, the CPU 3 stores an empty trunk list of the line trunk group recorded in the memory 4. Is read (step A5).

Here, the trunk information table J is not linked to this empty trunk list at all (see FIG. 2).
(See (d)), the CPU 3 requests the subscriber line trunk 5-1 to perform trunk busy processing, and the subscriber line trunk 5-1 notifies the subscriber telephone 1-1 of busy. To release the call (steps A6 and A7).

When one or more trunk information tables J are linked to the empty trunk list, the CPU 3 sets the trunk information table J linked at the top of the list to the empty list.
, And requests a trunk line corresponding to the trunk number to perform a trunk transmission process (steps A6, A8, A9). Referring to FIG. 2A, the trunk number is acquired from the trunk information table J2, and the line trunk 6-2 corresponding to the trunk number is acquired.
Request for trunk transmission processing. In other words, the central office trunk 6-2 is selected and captured, and the outgoing call processing is performed using the selected and captured empty trunk 6-2.

Thereafter, the CPU 3 releases the link of the trunk information table J2 of the selected empty trunk 6-2 and disconnects it from the list structure of the empty trunk list (step A10: see FIG. 2B). The exchange 2 'and the subsequent exchanges also establish paths one after another by the same trunk control. As a result, the call is established, and the call becomes possible.

[Release of Call] When the call is released after the end of the call, the processing is performed as follows. First, when the subscriber's telephone set 1-1 disconnects the call by hanging up the receiver or the like, the subscriber line trunk 5-1 of the exchange 2 performs an incoming trunk recovery process (step A11). For example, FIG.
When the subscriber line trunk 5-1 is restored from the state shown in (b), the CPU 3 requests the outgoing trunk 6-2 connected from the subscriber line trunk 5-1 to restore the trunk, and releases the call. Perform processing (Steps A12, A1)
3). After the completion of the call release processing, the CPU 3 sets the outgoing trunk 6
-2 trunk information J2 is linked to the end of the list structure of the empty trunk list (see FIG. 2C).

Conversely, when the call is released from the subscriber to which the subscriber telephone set 1-1 is connected, the trunk is restored and the call is released according to the above procedure. The CPU 3 links the trunk information table J2 of the outgoing trunk 6-2 to the end of the list structure of the empty trunk list.

In the manner described above, the exchange 2 receives the call connection request from the subscriber's telephone 1 and, even if the office trunks 6 to be connected are connected in a multi-line manner to form an office trunk group. It is possible to immediately select an empty trunk and catch the outgoing trunk without searching for an empty trunk at that time. Therefore, the exchange 2 does not search for an empty trunk in the line trunk group.
If the time required for the connection process of the call is shortened, and all exchanges that relay the call adopt the same trunk selection method,
As a result, the call connection between the subscribers is sped up.

The present invention is not limited to the above embodiment. For example, the office trunk groups and the number of office trunks forming each office trunk group may be determined according to the specifications of the exchange and the connection form of the associated trunk.

In addition to the method of operating links in a list-type structure as shown in FIG. 2, the empty trunk list may include an array (#) corresponding to the number of trunks forming a local trunk group as shown in FIG. Alternatively, a trunk number and trunk information may be allocated to the elements of each array, and the respective arrays may be recorded as a trunk information table J '.

In this case, the empty trunk list header H '
Record the array element numbers of the information table J 'of the vacant office line trunks, and when selecting an empty trunk at step A5 in FIG. 4, the trunk numbers are obtained from the trunk information table J' of the array elements. It reads out and requests the central office trunk corresponding to the trunk number to perform a calling process.
If the trunk list header H 'has an invalid value (for example, 0), it is considered that there is no available trunk at that time, and the trunk on which the call has been received is requested to perform trunk busy processing.

After the trunk transmission processing is completed, another empty trunk is searched, and if there is an empty trunk, the array element number of the trunk information table J 'is recorded again in the empty trunk list header H'. If there is no empty trunk, an invalid value (for example, 0) is recorded in the empty trunk list header H '. When the call is released, only when the empty trunk list header H 'has an invalid value (for example, 0), the array element number of the trunk information table J' of the outgoing trunk immediately before releasing the call is replaced with the empty trunk list header. Record again in H '. Even when this method is adopted, the control procedure of the CPU 3 is the same as that of the flowchart of FIG. 4 except that the operation of the empty trunk list header H 'is different. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[0031]

As is apparent from the above description, according to the present invention, an empty trunk is immediately selected from a multiline-connected office line trunk group when controlling a call connection in an exchange. Is possible,
The process of searching for an empty trunk after a call arrives is unnecessary, and the time required for call connection control in an exchange can be reduced. By adopting the trunk selection method of the present invention, the speed of call connection between subscribers can be increased. Further, in the exchange, the occupation time of the CPU required for connection control for one call is shortened, so that the call connection processing capacity per unit time of the exchange is improved, and as a result, the efficiency of line use is improved. This has the effect that it can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a communication system to which the present invention is applied.

FIG. 2 is a diagram exemplifying a change in a list structure of an empty trunk list held in a memory 4 of the exchange 2 in FIG. 1;

FIG. 3 is a configuration diagram of a trunk information table J in FIG. 2;

FIG. 4 is a flowchart for explaining a call connection control process in the exchange 2 shown in FIG.

FIG. 5 is a structural diagram showing another example of an empty trunk list.

[Explanation of symbols]

1 (1-1 to 1-n) ... subscriber telephone, 2 ... exchange, 3
... CPU, 4 ... memory, 5 (5-1 to 5-n) ... subscriber line trunk, 6 (6-1 to 6-m) ... office line trunk,
2 '... other exchange, 3' ... CPU, 4 '... memory, 6'
(6'-1 to 6'-m) ... office line trunk, J, J '... trunk information table, H, H' ... empty trunk list header.

Claims (4)

[Claims] 1. An exchange for selecting an empty trunk from a multiline-connected office trunk group and performing a calling process using the selected empty trunk when controlling call connection. Empty trunk list means for indicating a middle empty trunk; and empty trunk selecting means for selecting an empty trunk by referring to the empty trunk list means and controlling a call using the selected empty trunk during call connection control. And a trunk selection method. 2. An exchange for selecting a free trunk from a multi-line connected local trunk group and performing a calling process using the selected free trunk at the time of call connection control. A list structure of an empty trunk list in which the trunk information tables of the empty trunks are linked, and at the time of call connection control, an empty trunk is selected with reference to the empty trunk list, and a call is made using the selected empty trunk. A trunk selection system for performing processing. 3. An exchange for selecting a free trunk from a multi-line connected local trunk group and controlling a call using the selected free trunk when controlling call connection. A list structure of an empty trunk list in which the trunk information tables of the empty trunks are linked, and at the time of call connection control, an empty trunk is selected with reference to the empty trunk list, and a call is made using the selected empty trunk. Empty trunk selecting means for performing processing; trunk information table separating means for separating the trunk information table of the empty trunk selected by the empty trunk selecting means from the list structure of the empty trunk list; and trunk information table separating means for separating. The trunk information table of the empty trunk Trunk selection method is characterized in that a trunk information table addition means for adding later released list structure of the free trunk list. 4. The call control system according to claim 1, wherein, in the call connection control, if no empty trunk is in the list, all of the trunks in the multiline-connected trunk transformer group are in use. A trunk selection method comprising: means for determining that there is a call, and requesting a busy process for a trunk on which a call arrives.