JPH118697A - Telephone exchange network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system with excellent cost performance that copes efficiently with a fault. SOLUTION: In the system where pluralities of transmission installations T1, T2, T3, T7 are provided between exchanges 100 and 200, a control section 110 references a prescribed table with respect to a call of a connection object to select an optimum transmission installation and to connect it. On the occurrence of a fault in an operation transmission line T11 in the transmission installation T1, transmission line changeover devices 10, 20 are used to select a spare transmission line T1x. In the case that the changeover transmission by the spare transmission line T1 is not available, fault occurrence information is sent to the control section 110. Upon the receipt of the fault occurrence information, the control section 110 references again the table to conduct processing to select a new substitute transmission installation in place of the faulty transmission installation T1 and the transmission is continued by using the selected substitute transmission installation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone switching network system, and more particularly to a rescue processing technique when a failure occurs in a transmission line in a telephone switching network.

[0002]

2. Description of the Related Art With the spread of computers, voice,
Since all information such as characters and images is being transmitted via communication networks, the importance of systems such as public telephone exchange networks and private telephone exchange networks is expected to increase in the future. You. At present, a telephone switching network system generally used includes a large number of exchanges installed in various places and a large number of transmission facilities provided between these exchanges. The transmission equipment connecting the exchanges usually includes a plurality of transmission paths. Each transmission path may be constituted by a physical cable such as a conductive wire cable or an optical fiber cable, or may be constituted by a radio equipment or the like.

[0003] When a call to be connected is given, an individual exchange selects an optimal transmission facility through which the call is connected to another exchange to which the call is to be connected, and uses the selected transmission facility to transmit a call. Perform communication. Each exchange normally holds call routing data in the form of a table, and refers to this table to perform a process of allocating an optimal transmission facility for each call.

[0004] In a transmission facility provided between a pair of exchanges, an operation transmission line for normal operation and a spare transmission line for spare use are usually provided at a ratio of n: 1. I have. For example, in the case of a transmission facility including three operation transmission lines and one protection transmission line, in normal operation, signal transmission using three operation transmission lines is performed, and the protection transmission line Not used for transmission. However, if one of the three operation transmission lines fails, the transmission equipment
It has a function of detecting the occurrence of this failure and switching the operation transmission line in which the failure has occurred to the backup transmission line. As described above, if the transmission equipment is provided with redundancy as a whole, even if each transmission path is interrupted, the transmission equipment as a whole can perform the transmission function without any trouble.

[0005]

As described above, in the conventional general telephone switching network system, by providing a spare transmission line in each transmission facility, measures are taken in case of a failure. ing. However, when a relatively large accident occurs, such a backup transmission line alone
We cannot cope enough. For example, as in the above-described example, in the case of a transmission facility including three operation transmission lines and one protection transmission line, if a failure occurs in one operation transmission line, this is set to the protection transmission line. Can be dealt with. However, in the case where two or more active transmission lines are simultaneously affected, one call (a request for information transmission using one transmission line) can be remedied by switching to a spare transmission line. However, another call cannot be remedied, the call must be released, and the communication is interrupted. Further, even when a failure occurs in the backup transmission line itself, the original rescue function cannot be performed.

[0006] Of course, if the number of spare transmission lines included in each transmission equipment is increased, the ability to cope with a failure can be improved. Will occur. Further, in the conventional telephone switching network system, it is necessary to provide at least one spare transmission line even for transmission equipment installed in a section with a low utilization rate, and an ideal form is not always desirable in terms of cost performance. Not adopted.

It is an object of the present invention to provide a telephone switching network system which can deal with a failure more efficiently and has good cost performance.

[0008]

[Means for Solving the Problems]

(1) A first aspect of the present invention has a plurality of exchanges and a plurality of transmission facilities provided between these exchanges, and a plurality of transmission facilities are connected to one exchange, When a call to be connected is given, each exchange refers to predetermined data to make a switch corresponding to the call destination.
In a telephone switching network system having a function of selecting one transmission facility and transmitting the information content of a call using the selected transmission facility, the selected transmission facility may be disturbed during the transmission of the information content. If the transmission of the fault can no longer be performed, the fault transmission equipment is configured to transmit the fault occurrence information from the faulty transmission equipment to the exchanges connected to both ends of the faulty transmission equipment. In addition, an exchange newly selects an alternative transmission facility for transmitting information content by referring to data, and performs processing for transmitting information content using the alternative transmission facility.

(2) The second aspect of the present invention is the above-mentioned first aspect.
In the telephone switching network system according to the aspect, a detour is set via another exchange different from the other exchange directly connected by the fault transmission equipment, and the transmission equipment on this detour is selected as an alternative transmission equipment. It is something to do.

(3) A third aspect of the present invention is the above-mentioned first aspect.
In the telephone switching network system according to the aspect, the exchange is provided with a function of recognizing the current transmission load of each transmission facility based on the usage status of each of the plurality of transmission facilities connected to the exchange, and is selected as an alternative transmission facility. When there are a plurality of possible candidates, one or more specific candidates are selected as alternative transmission facilities based on the transmission load of each candidate.

(4) The fourth aspect of the present invention is the above-mentioned first aspect.
In the telephone switching network system according to the aspect, the priorities are set for each of the calls to be connected, and when trouble occurs in the transmission equipment, the priority is set according to the priority order set for each call. A transmission process using a transmission facility is performed.

(5) The fifth aspect of the present invention is the above-mentioned first aspect.
In the telephone switching network system according to the aspect, each transmission facility is provided with an operation transmission line used during normal operation, a spare transmission line used as a spare, and a transmission line switching device that switches a transmission line used for actual transmission, During normal operation without interruption,
The transmission line switching device performs switching such that the operation transmission line is used, and when a failure occurs in the operation transmission line, the transmission line switching device performs switching such that the backup transmission line is used. In the case where normal transmission cannot be performed using a path, fault occurrence information is transmitted to the exchange side.

(6) The sixth aspect of the present invention is the above-mentioned first aspect.
In the telephone exchange network system according to the aspect, the transmitting-side exchange is provided with a function of adding predetermined additional information to the information to be transmitted and transmitting the information, and whether the additional information has been correctly transmitted to the receiving-side exchange. A function of confirming whether or not failure occurs has been provided, and if the confirmation has not been performed for a predetermined period of time, the failure transmission equipment is treated as having transmitted failure occurrence information to the exchange.

(7) A seventh aspect of the present invention is the above-mentioned first aspect.
In the telephone exchange network system according to the aspect, a common control line for transmitting a control signal between the respective exchanges is further provided, and when the failure occurrence information is transmitted, the exchange on the transmission side or the reception side of the failure transmission equipment is provided. Thus, an alternative transmission facility is selected, and information on the selected alternative transmission facility is transmitted to a receiving-side or originating-side exchange via a common control line.

(8) The eighth aspect of the present invention is the above-mentioned first aspect.
In the telephone switching network system according to the aspect, the arithmetic processing for selecting an alternative transmission facility is performed in a control system provided outside the exchange, and the alternative transmission facility is selected according to an instruction from the control system. is there.

[0016]

FIG. 1 is a block diagram showing the configuration of a general telephone exchange network system to which the present invention is applied. Here, three exchanges 100, 200, 300
And a simple example composed of transmission equipments T1 to T8 connected thereto, but in reality, a larger number of switches and a larger number of switches provided between these switches are provided. More complex telephone switching network systems have been built with transmission facilities. As shown, a plurality of transmission facilities are connected to one switch, and each switch
When a call to be connected is given, a function of selecting one transmission facility according to the connection destination of the call and performing communication of the call using the selected transmission facility is performed.

For example, in the case of a general public telephone line, routing data of a call indicating the correspondence between a predetermined area code and a predetermined transmission facility is prepared in each exchange as a table. , The optimal transmission equipment for each call will be selected.
Specifically, for example, in the exchange 100, for the area code "045", the first priority: transmission equipment T1, the second priority: transmission equipment T2, and the third priority: transmission equipment T
If a table such as 3,... Is prepared, for a call indicating a connection destination with an area code “045”,
The exchange 100 first performs a process of preferentially selecting the transmission facility T1. At this time, if the transmission load of the transmission facility T1 having the first priority is equal to or higher than a predetermined reference, the transmission facility T2 having the second priority is selected.
As described above, each switching equipment refers to the preset table and the transmission load of each transmission equipment at the present time for the given individual call, and determines the transmission equipment determined to be most appropriate at that time. Is selected, and call connection processing is performed using the selected transmission equipment.

A plurality of transmission paths are prepared for each transmission facility. FIG. 2 is a block diagram showing the configuration of one transmission facility T1 shown in FIG. 1 in detail. In this example, the transmission facility T1 has three operation transmission paths T11 and T1.
2, T13 and one spare transmission line T1x. Each transmission line T11, T12, T13, T
The transmitting and receiving devices 11/21, 12 /
22, 13/23, 1x / 2x are connected, and a process of converting the information content of the call (for example, voice) into some physical communication signal and transmitting / receiving the same via a transmission path is performed.
Each transmission path may be constituted by a physical cable such as a conductive wire cable or an optical fiber cable, or may be constituted by a radio equipment, etc., and the transmission / reception devices 11 to 1x and 21 to 2x It has a function of transmitting and receiving communication signals in a form suitable for the road.

The transmission / reception devices 11, 12, and 13 are connected to end points a1, a2, and a3 via the transmission line switching device 10, and the transmission / reception devices 21, 22, and 23 are connected to the transmission line switching device 20.
Are connected to the end points b1, b2, and b3. Therefore, during normal operation, the end points a1 and b1 are connected via the operation transmission line T11, and the end points a2 and b2 are
It is connected via the operation transmission line T12, and the end points a3 and b3 are connected via the operation transmission line T13. At this time, the backup transmission line T1x is not provided for actual operation, but test communication is performed between the transmission / reception devices 1x / 2x, and regular maintenance is performed.

Each transmission line has a function of transmitting signals bidirectionally. For example, the operation transmission line T11 is
→ Signal transmission in the direction toward 21, and conversely,
It has a function of performing signal transmission in the direction from 1 to 11. If it is recognized that some trouble has occurred in the transmission via the operation transmission line T11, the transmission line switching devices 10 and 20 switch this operation transmission line T11 to the standby transmission line T11.
The processing for switching to 1x is executed. By performing such switching, even if a failure occurs in the operation transmission line T11, signal transmission between the end points a1 / b1 is performed by the protection transmission line T11.
Through 1x, it will be performed without hindrance.

Such switching processing is performed in the operation transmission line T1.
2, and T13. That is, even if any of the operation transmission paths T11, T12, and T13 has a failure, the transmission path switching devices 10 and 20 perform the process of switching the failed transmission path to the backup transmission path T1x. . Thus, each transmission facility has
Each is provided with redundancy, and even when a failure occurs in the transmission path, an internal switching process is performed. In other words, in the conventional telephone switching network system, since each transmission facility has a function to cope with the trouble of the transmission line, each exchange does not have a function to perform any countermeasure. However, there is a case where a sufficient countermeasure cannot always be performed only by a countermeasure function on the individual transmission facility side. For example, in the case of the example shown in FIG. 2, if both the operation transmission lines T11 and T12 are affected, only one spare transmission line T1x is prepared. The call (information transmission request using one transmission line) can be repaired using the backup transmission line T1x, but the other call must be released and the communication interrupted. become.

The present invention proposes a method for solving such a conventional problem, and its basic technical idea is to provide a switching device with a function when an individual transmission path is interrupted. , Means for taking measures. That is, in the telephone switching network system according to the present invention, when a failure occurs in the transmission equipment during communication of a call and transmission becomes impossible, the switching equipment connected to both ends of the failure transmission equipment in which the failure occurred is transmitted. When the fault occurrence information is transmitted, the exchange refers to the data again to newly establish an alternative transmission facility for continuing the call communication. It has a function of selecting and performing a process of restarting call communication using this alternative transmission facility. In particular, as shown in FIG. 2, a spare transmission line is provided on the transmission equipment side, and in the unlikely event that there is a function to switch from a normal operation transmission line to a spare transmission line and to cope with it. First, a measure on the transmission equipment side to switch to the spare transmission path with priority is executed. Then, when normal transmission cannot be performed even when the backup transmission path is used (when the number of backup transmission paths corresponding to the failed transmission path cannot be secured), the failure occurrence information is transmitted to the exchange. In this way, the countermeasures on the exchange side are executed.

Next, the coping function on the exchange side according to the present invention will be described with reference to the block diagram of FIG.
FIG. 3 is a block diagram showing two exchanges 100 and 200 and a part of transmission equipment connected between them. The transmission equipment T1 shown by the dashed line block in the figure is the same as the transmission equipment T1 shown in FIG. Transmission equipment T2, T3, T7 also indicated by a chain line.
Also has the same configuration as the transmission equipment T1 shown in FIG.
As shown in FIG. 1, the transmission facilities T1 and T2 are facilities for directly connecting the exchanges 100/200, while the transmission facilities T3 and T7 are connected via another exchange 300 to the exchange facilities 100/200. Is a facility that indirectly connects

In FIG. 3, the exchanges 100 and 200 are also indicated by dashed lines. The central components of these exchanges are the control units 110 and 210. The control units in each exchange are connected by a common control line C. This common control line C is used exclusively for transmitting control signals used for call processing control between the exchanges. Each of the control units 110 and 210 performs a process of transmitting and receiving the information content of the call as a communication signal via the endpoints a1 to a3 and the endpoints b1 to b3. At this time, the determination as to which end point the received call is to be connected to is determined by referring to the table of the routing data of the call as described above. For example, assuming that a call indicating the connection destination of the area code “045” is transmitted to the control unit 110, the control unit 110
Refers to the stored table and finds the area code "0
45, select a transmission facility suitable for the connection destination. The control unit 110 has a function of recognizing the transmission load of each transmission facility at that time based on the usage status of each transmission facility. A process for selecting an optimal transmission facility is performed with reference to the indicated information. In the embodiment shown here, the selection of which transmission line of which transmission facility is to be used is made. For example, when the selection of using the operation transmission line T11 of the transmission facility T1 is made, the connection of the call via the end point a1 is performed. Will be performed.

Thus, if any trouble occurs in the operation transmission line T11 during transmission through the operation transmission line T11, first, the transmission equipment T1
On the side, a countermeasure is taken against this hindrance. That is, the transmission line switching devices 10 and 20 operate the operation transmission line T1.
1 is switched to the backup transmission line T1x. If the processing can be dealt with by the transmission facility, the exchange does not need to take any action. That is, the communication signal transmitted from the control unit 110 to the end point a1 is received by the control unit 210 via the end point b1, as before the occurrence of the trouble. However, when the operation transmission line T12 is further provided with a communication while the protection transmission line T1x is used for communication due to the operation transmission line T11, the transmission equipment T1 can no longer deal with the problem. Originally,
Either the first call that should have used the operation transmission line T11 or the second call that should have used the operation transmission line T12 can be relieved by using the backup transmission line T1x. However, the other cannot be rescued and must be released.

According to the present invention, when a failure that cannot be dealt with on the transmission equipment side occurs during transmission of the call information content, the faulty transmission equipment in which the failure has occurred is connected to both ends thereof. The fault occurrence information is transmitted to the exchange that has been activated. In the above example, the transmission facility T1
Therefore, the failure occurrence information is transmitted to the exchanges 100 and 200 connected to both ends. The transmission of the failure occurrence information may be performed by any means. For example, despite the fact that any one of the operation transmission lines T11 to T13 has a problem, the protection transmission line T
When switching to 1x cannot be performed, the transmission path switching devices 10 and 20 in the transmission equipment T1 send the control unit 11
0, 210 may be provided with a fault occurrence signal. Further, as described above, each transmission path has a function of transmitting a signal in both directions, and the control unit in each exchange can confirm whether or not the information has been transmitted without any trouble. Therefore, each control unit monitors the information being transmitted and received, and when the transmission is not correctly performed, recognizes that some trouble has occurred in the selected transmission equipment, and based on this recognition, the trouble occurrence is detected. You may make it handle as transmission of information. Specifically, the transmitting-side exchange may have a function of adding predetermined additional information to the information to be transmitted and transmitting the information, and the receiving-side exchange may monitor this additional information. Good. The receiving exchange is provided with a function for confirming whether or not the additional information has been correctly transmitted. If the confirmation cannot be performed for a predetermined period of time, the faulty transmission equipment switches the receiving exchange to the receiving exchange. May be handled as having transmitted the failure occurrence information to the user. Further, as shown in FIG. 3, since a common control line C for transmitting a control signal is provided between the exchanges, a failure occurs from one exchange to another exchange via the common control line C. It is also possible to transmit generated information. For example, the exchange 200 on the receiving side
When it is recognized that the transmission is not correct,
To that effect, the exchange 10 on the transmitting side communicates via the common signal line C.
It is possible to report to 0.

According to the present invention, when such fault occurrence information is transmitted, the control unit in each exchange takes a measure to temporarily suspend the call related to the fault, and again performs the call for this call.
With reference to the table, a new alternative transmission facility is selected, and processing for reconnecting the call on hold using this alternative transmission facility is performed. For example, in the example shown in FIG. 3, from the end point a2 to the end point b2 via the operation transmission line T12.
It is assumed that when a predetermined call is connected toward, a problem occurs in the operation transmission path T12. At this time,
If the backup transmission line T1x can be used instead of the operation transmission line T12, the transmission transmission line T1
1x, the protection line T1x
Is not available, the transmission facility T1 transmits fault occurrence information to the exchanges 100 and 200. Then, the control unit 110 or 210 controls the operation transmission line T1.
2 is used to temporarily suspend the call being communicated, and the control unit 110 on the call originating side refers to the routing data table relating to the connection destination again for the temporarily suspended call. , A process of newly selecting an alternative transmission facility is performed. In the case of the above example, for example, the transmission facility T2 is newly selected as an alternative transmission facility, and the call on hold is reconnected via the transmission facility T2.

When selecting the alternative transmission equipment, a detour is set via another exchange different from the other exchange directly connected by the faulty transmission equipment, and the transmission equipment on this detour is set. It may be selected as an alternative transmission equipment. For example, in the case of the example shown in FIG. 3, if the transmission equipment T2 is selected as an alternative transmission equipment instead of the faulty transmission equipment T1, the alternative transmission having exactly the same path is performed. It is also possible to select T7 as an alternative transmission facility. In the latter case, a detour from the exchange 100 to the exchange 200 via the exchange 300 is formed, but the final connection destination is the same. Of course, if such a detour is formed, the transmission efficiency will be reduced, but at least a situation in which the call is released and the call is interrupted can be avoided. As far as possible, it is preferable to consider it as a candidate for an alternative transmission facility.

In selecting the alternative transmission equipment, it is preferable to consider the transmission load of each transmission equipment. That is, each exchange is provided with a function of recognizing the transmission load of each transmission facility at the present time based on the usage status of each of the plurality of transmission facilities connected thereto, and a candidate that can be selected as an alternative transmission facility is provided. Are present, a specific candidate (1) that can be determined to be appropriate based on the transmission load of each candidate
However, the method is not limited to this and may be assigned to a plurality of candidates according to the situation). More specifically, if a predetermined function is defined in consideration of the CPU usage rate of the exchange at the time of failure, the number of free channels in the detour, etc., an optimal selection may be made based on this function. Good.

On the other hand, if a fault occurs in a plurality of calls at the same time and it becomes necessary to select an alternative transmission facility for each of the plurality of calls, priority is set in advance for each of the calls. It is preferable that the processing for selecting the alternative transmission equipment be performed in order according to the priority order set for each call. If the capacity of the alternative transmission equipment that is actually available is less than the number of failed calls, only some of the calls will be rescued, but the alternative processing will be performed in order according to the priority. By doing so, it is possible to rescue calls with higher priority.
In practice, a predetermined function is defined in consideration of the CPU usage rate of the exchange at the time of failure, the number of free channels in the bypass, and the like, and the number of calls to be remedied is determined based on this function. It is good to

As described above, since the common control line C is provided between the exchanges, when the transmission is restarted using the alternative transmission equipment, the common control line C is used to newly select the transmission line. It is preferable to exchange information specifying the alternative transmission equipment. For example, when the fault occurrence information is transmitted, when the exchange on the call originating side of the faulty transmission facility selects an alternative transmission facility, the information on the selected alternative transmission facility is transmitted to the common control line C. If the call is transmitted to the exchange on the receiving side of the call, the contents of the alternative transmission can be confirmed between the exchanges at both ends of the faulty transmission equipment, and the more reliable alternative transmission becomes possible (of course, (Alternative transmission equipment may be selected by the switch on the call receiving side. In this case, information on the selected alternative transmission equipment may be transmitted to the switch on the call transmitting side via the common control line C.) . Specifically, a reconnection signal using the line number used in the faulty transmission equipment as an additional information element is transmitted from the switch on the call originating side to the switch on the call receiving side via the common control line C. What should I do? The switch on the call receiving side refers to the line number included in the reconnection signal, performs processing necessary for reconnection, and returns a reconnection completion signal to the switch on the call originating side. Then, in both exchanges, the call on hold may be immediately reconnected to resume the call. If the call originating party or the call receiving party performs an operation of disconnecting the call during the temporary hold, the exchange performs a process of releasing the call at that time. This can be communicated to the exchange of the other party via the common control line C.

When the faulty transmission equipment is restored due to the elimination of the trouble that has occurred, the call after the restoration is transmitted using the transmission equipment that should be used (the restored transmission equipment). For a call that has already been transferred to the alternative transmission facility, transmission by the alternative transmission facility may be continued as it is. Of course, if necessary, for calls that have already been transferred to the alternative transmission equipment,
Processing to return to transmission by the original transmission equipment (return processing)
May be performed.

FIG. 4 is a flow chart showing an example of a processing procedure executed when a failure occurs in a transmission line in the telephone switching network system according to the present invention. First, when a failure occurs in any of the operation transmission lines, in step S1,
The failure is detected by the transmitting and receiving devices connected to both ends of the operation transmission line where the failure has occurred. And step S
In 2, it is determined whether there is a spare transmission path. When the spare transmission line T1x is provided as in the transmission equipment T1 shown in FIG. 3, it is checked in step S3 whether or not the spare transmission line is vacant. Further, in step S4,
It is checked whether or not this backup transmission line functions normally. And if there is a spare transmission line functioning normally,
In step S5, a transmission path switching operation is performed. That is, the operation transmission path in which the failure has occurred is switched to the backup transmission path. As a result, the operation of the transmission facility as a whole is continued without any problem. This step S
The processing procedures 1 to S5 are known processing procedures that are also executed in the conventional telephone switching network system.

On the other hand, when it is determined in step S2 that the transmission equipment does not have a backup transmission line itself (in a conventional system, it is general to provide a backup transmission path in all transmission facilities). However, in the system of the present invention, it is also possible to omit the spare transmission line as described later), or if it is determined in step S3 that there is no free space in the spare transmission line, or In step, if it is determined that an abnormality has occurred in the backup transmission path, the processing in step S6 and subsequent steps is executed. The processing after step S6 is processing unique to the present invention.

First, in step S6, the transmission facility including the transmission line in which the fault has occurred transmits fault occurrence information to the exchanges at both ends thereof, and the exchange detects the failure. As described above, the fault occurrence information does not necessarily have to be information transmitted by any signal that is actively transmitted from the transmission equipment side to the exchange side, and the exchange side monitors the communication signal being transmitted while monitoring the transmission signal. The information may be voluntarily recognized. When such fault occurrence information is transmitted to the exchanges and the failure detection is performed by the exchanges, the call is temporarily held by each exchange in step S7. Subsequently, the exchange on the call transmitting side executes an alternative route selection process for the temporarily suspended call. If the alternative route can be selected, the process proceeds from step S8 to step S9.
Then, recall setting for this alternative route is performed. That is, both exchanges reconnect the call that has been put on hold using the selected alternative route. as a result,
In step S10, the call is continued. On the other hand, if it is determined in step S8 that an alternative route cannot be selected (if there is no alternative transmission facility available at that time), step S1 is executed.
Proceeding to 1, the temporarily held call is disconnected.

As described above, in the telephone switching network system according to the present invention, a call that could not be remedied conventionally can be remedied by performing alternative transmission using alternative transmission equipment. Further, if the present invention is utilized, it is possible to construct a telephone switching network system using transmission equipment having no backup transmission path. That is, in the conventional telephone switching network system, in practice, it is necessary to provide at least one backup transmission line in each transmission facility in case of a failure of the transmission line. If a switching network system is used, even if transmission equipment without a backup transmission path is included, in the unlikely event that reconnection using an alternative transmission equipment is possible, a major problem in practical use is Does not occur.

As described above, the present invention has been described based on the illustrated embodiments. However, the present invention is not limited to the embodiments described here, and can be implemented in various other modes. For example, in the above-described embodiment, the arithmetic processing for selecting the alternative transmission equipment is performed by the control unit provided inside each exchange, and the exchange autonomously performs the call rescue processing. A control system may be provided outside each exchange, and the rescue process may be performed according to an instruction from the control system. That is, the arithmetic processing for selecting the alternative transmission equipment is performed in an external control system, and the control system gives an instruction to each exchange to perform the alternative transmission.
The alternative transmission process may be executed based on an instruction from the control system. As described above, by using the control system outside the exchange, it is possible to centrally manage the processing of the alternative transmission for a plurality of exchanges.

In the above-described embodiment, whether or not to rescue a specific call is always determined by the exchange on the call originating side. This determination may be made. Also,
A special signal (for example, a special ISUP signal or a non-line-compatible signal) may be exchanged between the two exchanges using the common control line C, and a decision on alternative transmission may be made by negotiation between the two exchanges. Absent.

[0039]

As described above, according to the telephone switching network system of the present invention, even if a failure occurs in the transmission equipment, reconnection is performed by the newly selected alternative transmission equipment. As a result, it is possible to provide a telephone exchange network system that can deal with the problem more efficiently and has good cost performance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a general telephone switching network system to which the present invention is applied.

FIG. 2 is a block diagram showing a configuration of one transmission facility T1 shown in FIG. 1 in detail.

FIG. 3 is a block diagram showing a configuration of a telephone switching network system according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an example of a processing procedure executed when a failure occurs in a transmission line in the telephone switching network system according to the present invention.

[Explanation of symbols]

 10, 20 transmission line switching device 11-1x, 21-2x transmission / reception device 100, 200, 300 switching device 110, 210 control unit a1-a3, b1-b3 end point C common control line T1-T8 transmission Equipment T11 to T13: Operation transmission line T1x: Standby transmission line

Claims (8)

[Claims] 1. A plurality of exchanges, and a plurality of transmission facilities provided between the exchanges, wherein a plurality of transmission facilities are connected to one exchange, and each exchange has a connection target When a given call is given, by referring to predetermined data, one transmission facility corresponding to the connection destination of the call is selected, and the information content of the call is transmitted using the selected transmission facility. In a telephone switching network system having a function, during transmission of the information content, if the selected transmission equipment fails, and the transmission of the information content cannot be performed, the troubled transmission equipment from which the failure occurred is transmitted. The failure occurrence information is transmitted to the exchanges connected to both ends thereof, and when the failure occurrence information is transmitted, the exchange refers to the data to transmit the information content. Was Telephone network system newly selected alternate transmission equipment, and having a function of transmitting the information content by using the alternate transmission facilities. 2. The telephone switching network system according to claim 1, wherein a detour is set via another exchange different from the other exchange directly connected by the faulty transmission equipment, and the transmission on the detour is set. A telephone switching network system, wherein equipment is selected as an alternative transmission equipment. 3. The telephone exchange network system according to claim 1, wherein a function of recognizing a current transmission load of each transmission facility based on a use state of each of the plurality of transmission facilities connected to the exchange is provided to the exchange. A telephone switching network system wherein, when there are a plurality of candidates that can be selected as alternative transmission facilities, one or more specific candidates are selected as alternative transmission facilities based on the transmission load of each candidate. . 4. The telephone switching network system according to claim 1, wherein priorities are set for each of the calls to be connected, and when a problem occurs in the transmission equipment, the priority is set for each call. A telephone switching network system that performs transmission processing using an alternative transmission facility in accordance with the order of priority. 5. The telephone switching network system according to claim 1, wherein each transmission facility switches between an operation transmission line used during normal operation, a spare transmission line used as a spare, and a transmission line used for actual transmission. A path switching device is provided, and during normal operation without any trouble, switching is performed by using the operation transmission line by the transmission line switching device, and when a trouble occurs in the operation transmission line, the transmission line switching device Switching is performed so as to use the backup transmission path, and when normal transmission cannot be performed even using the backup transmission path, failure occurrence information is transmitted to the exchange side. A telephone switching network system. 6. The telephone exchange network system according to claim 1, wherein a function of adding predetermined additional information to information to be transmitted and transmitting the information is provided in an exchange on a transmission side, and an exchange on a reception side is provided in an exchange on a reception side.
A function for confirming whether or not the additional information has been correctly transmitted is provided, and when the confirmation is not performed for a predetermined period, it is assumed that the failure occurrence information is transmitted from the failure transmission equipment to the exchange. A telephone switching network system. 7. The telephone switching network system according to claim 1, further comprising a common control line for transmitting a control signal between the respective exchanges, wherein when a failure occurrence information is transmitted, the failure transmission equipment is provided. A telephone exchange characterized by selecting an alternative transmission facility by an originating or receiving exchange, and transmitting information on the selected alternative transmission equipment to the receiving or originating exchange via the common control line. Web system. 8. The telephone switching network system according to claim 1, wherein the arithmetic processing for selecting an alternative transmission facility is performed in a control system provided outside the exchange, and the processing of the alternative transmission facility is performed according to an instruction from the control system. A telephone switching network system, wherein a selection is made.