JP2002027107A - Fault notice system for multiplexed communication network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching system that is less affected by a fault. SOLUTION: A central arithmetic processing section 110A controls a connecting operation of a communication path of a switch 114A and generates a reset signal 122A at a prescribed time interval when the operation of the central arithmetic processing section 110A is normal. A fault monitor section 112A is initialized by a reset signal 122A and does not generate a time-out signal 94 when the operation of the central arithmetic processing section 110A is normal. For example, when the operation of the central arithmetic processing section 110A of an exchange 74 of system 0 is not normal at a lapse of a time set longer than the generation interval of the reset signal 122A, the fault monitor section 112A transmits the time-out signal 94 to an exchange 76 of a 1 system. A central arithmetic processing section 110B in system 1 exchange 76 transmits a system-down signal to lines 84, 86, and 66 via interface sections 102B, 104B, 106B in response to a time-out signal 124. Thus, the fault notice system informs opposite switching systems 12, 42 about the occurrence of a fault in the central arithmetic processing section 110A and the switching systems 12, 42 bypass the exchange 74 and set a communication path via the exchange 76.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure reporting system for a multiplex communication network, and more particularly, to a failure reporting system for a multiplex communication network in which a plurality of communication paths can be set by a redundantly configured switching system. Things.

[0002]

2. Description of the Related Art In order to avoid a failure in a communication network and secure reliability, a multiplex system may be constructed by arranging a plurality of exchanges having substantially the same configuration. For example, in a communication network, two systems of exchanges, that is, system 0 and system 1
A duplex system is constructed by configuring a switching system including a system switch. This duplex system normally operates both the 0-system switching system and the 1-system switching system.
That is, the communication paths are set such that the processing loads of the 0-system and 1-system exchanges are substantially equal.

The exchange includes a communication path switch, a central processing unit (CPU) for controlling the switch, and a line interface apparatus. When a failure occurs in any of the exchanges, it is closed and call processing is continued with only the exchanges in which no failure has occurred. For example, when a failure occurs in any device or line included in the exchange, a communication path is set around the exchange including the failed device or line, and the process is continued.

[0004]

For example, when a failure occurs in a line interface device, a clock exchange or a frame synchronization is lost in a digital line, so that the other party switching system can know the occurrence of the failure in the line. Therefore, another communication path can be set under the control of the central processing unit.
On the other hand, if a failure occurs in the central processing unit itself, the operation program is reloaded, the failure management program is started, the line interface is initialized, and then restarted. In the meantime, the calling switching system
Until a failure in the called switching system is recognized, the communication request signal is continuously or repeatedly transmitted to the failed switch. The switching system on the called side cannot perform call processing during the initialization processing in the central processing unit. Therefore, even if a communication request signal is received before the call processing is restarted, a call loss occurs.

[0005] Such a call loss increases sharply because the fault transmission time increases as the scale of the communication system increases. Therefore, the quality of the telecommunication service that can be provided may be degraded.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a fault reporting system for a multiplex communication network in which the influence of a fault is smaller than in the prior art.

[0007]

SUMMARY OF THE INVENTION A fault reporting system for a multiplexed communication network according to the present invention includes first and second lines heading for a first route and a second route different from the first route. A first exchange for accommodating third and fourth lines going there and establishing a communication path between the first and third lines, and a second exchange for establishing a communication path between the second and fourth lines. A first communication device, wherein the first communication device includes a first communication device, the first communication device accommodating the first and third lines, and a communication path for setting a communication path between the first and third lines; Control means for setting a communication path between the first and third lines in the first communication path means, and monitoring the operation of the first control means. A first fault monitoring means for outputting a fault information signal upon detection of an abnormal operation; And a second communication path means for accommodating the fourth and fourth lines and setting a communication path between the second and fourth lines, and controlling the second communication path means. And a second control means for setting a communication path between the fourth line and the first network, wherein the communication network connects a fault information signal from the first fault monitoring means to the second control means. Upon receiving a fault information signal from the first fault monitoring means, the second control means controls the second communication path means and causes the first switch to connect to the second and fourth lines. Is transmitted.

An exchange according to the present invention accommodates a plurality of lines and establishes a communication path between the plurality of lines, controls the communication path means, and communicates between the plurality of lines in the communication path means. Control means for setting the path, and monitoring the operation of the control means, when detecting an abnormal operation of the control means,
And a failure monitoring means for outputting a failure information signal. The communication path means is connected to the failure monitoring means, and sends a failure indication signal to a plurality of lines when receiving the failure information signal from the failure monitoring means.

The fault reporting system for a multiplexed communication network according to the present invention also includes first and second lines directed to a first route, and third and third routes directed to a second route different from the first route. A first switch for accommodating four lines and setting a communication path between the first and third lines, and a second switch for setting a communication path between the second and fourth lines; A first communication unit that accommodates the first and third lines and sets a communication path between the first and third lines;
Controlling the first communication path means, setting a communication path between the first and third lines in the first communication path means, and monitoring the operation of the first control means; A first fault monitoring means for outputting a fault information signal when detecting an abnormal operation of the first control means, wherein the first communication path means is connected to the first fault monitoring means, When a fault information signal is received from the fault monitoring means, a fault indication signal may be transmitted to the first and third lines.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a multiplex communication network fault reporting system according to the present invention; Referring first to FIG. 2, an embodiment of a multiplexed communication network 10 according to the present invention comprises a plurality of terminal units 20, 30, and a plurality of switching systems 40, 42, 12, 14 connected as shown. This is a switching system that exchanges and relays calls originating and terminating between 20, 30 by switching systems 40, 42, 12, and 14. In this communication network 10, switching systems 12 and 14 are duplexed into a system 0 and a system 1, respectively. In the redundantly configured systems 12 and 14, the occurrence of a fault in a line or a device is monitored, and one of the systems is monitored. When the occurrence of a failure in a system is detected, a bypass is made to the other system so that the influence of the failure is minimized.

In the present embodiment, the terminal devices 20 and 30 are communication terminal devices having a digital interface,
For example, it is a data home device such as a digital telephone, an image terminal device, and a data terminal device that has a line termination function and can perform data communication. Terminal 20 is connected to switching system 40 by a subscriber line 50, and terminal 30 is similarly connected to switching system 42 by a subscriber line 54. Although only two terminals 20 and 30 are shown, it will be appreciated that a greater number of terminals are similarly connected to switching systems 40 and 42.

Each line in the multiplex communication network 10 is
An electrical or optical communication line capable of transmitting digital signals. The digitized signal contains various information such as codes, audio, and images. In the following description,
The signal is indicated by the reference number of the connecting line in which it appears.

The switching system 12 includes a system 0 switching system 70 and a system switching system 1.
The system switch 72 is included. The switching system 40 is connected by a line 60 to a system 0 switch 70 in the switching system 12, and
A connection 62 is connected to the first system switch 72 in the switching system 12. The exchange system 40 includes the terminal device 20 accommodated therein.
From the subscriber line 50, select an outgoing line 60 or 62, set a communication path between the incoming and outgoing lines, monitor the state of the communication path, and release the connection. It has a subscriber line switching function. In the switching system 42, when a call is made from any of the terminal devices 20, the switching system 42
In the present embodiment, the selection of the two (or route) lines 60 or 62 in 40 performs connection control for distributing calls to the lines 60 or 62 so that the processing loads of the 0 system and the 1 system are equalized. . Alternatively, an active / standby configuration may be adopted in which one of the lines 60 and 62 is used as a working system and the other is used as a protection system, and when a failure occurs, the protection system is used as a working system.

The switching system 42 may have the same configuration as the switching system 40. The switching system 42 is connected by a line 64 to a system 0 switch 74 in the switching system 14 and by a line 66 to a system 1 switch 76 in the switching system 14.

The system 0 switch 70 of the switching system 12
Is connected to the system 0 switch 74 of the switching system 14, and is connected to the system 1 switch 76 of the switching system 14 by the line 84. Similarly, the first system switch 72 of the switching system 12
Are connected by a line 82 to a system 0 switch 74 of the switching system 14 and by a line 86 to a system 1 switch 76 of the switching system 14. Further, in the switching system 12, the system 0 switch 70 and the system 1 switch 72 are connected to signal lines 90 and 92.
And likewise in the switching system 14
The system switch 74 and the system switch 76 are interconnected by signal lines 94 and 96.

The switching system 12 detects a connection request from an accommodated incoming trunk line, selects an outgoing line of a corresponding route, sets a communication route between the incoming and outgoing lines, and monitors the state of the communication line. And has a relay switching function to release the setting. The switching system 14 has the same configuration and function as the switching system 12, and is connected to the 0-system switching units 74 and 1 connected as shown.
Including system switch 76. A multiplex configuration having more than two redundant systems may be employed.

The switching system 14 will be described in more detail. Referring to FIG. 1, the switching system 14
The 0-system switch 74 in the interface unit (I / F) 102
A, 104A, 106A, a central processing unit (CPU) 110A, a failure monitoring unit (WDT) 112A, and a switch 114A, which are connected as shown. Similarly, the first system switch 76 includes interface units 102B, 104B, 106B, a central processing unit 110B,
It comprises a fault monitoring unit 112B and a switch 114B.
Taking the example of system 0 switch 74 of switching system 14 as an example, this would accommodate three routes: lines 80 and 82 to system 0 switches 70 and 72 of switching system 12, respectively, and line 64 to switching system 42. Have been. Exchange systems12
Line 80 from the interface unit 102A of the system 0 switch 74.
And the line 82 is connected to the interface unit 104A. The line 64 from the switching system 42 is connected to the interface unit 106A of the system 0 switch 74. Similarly, in the 1-system switch 76, the line 86 is connected to the interface section.
To line 102B, line 84 to interface 104B, and line 66
Is connected to the interface unit 106B. Of course, each of these lines 80, 82 and 64 may have a plurality of lines.

The 1-system switch 76 has the same configuration as the 0-system switch 74. Therefore, the description will be continued with the system 0 switch 74 as an example. Interface units 102A, 104A and 106A are all connected to switch 114A. Interface section
102A, 104A, and 106A are interface function units that have the same configuration, and match communication protocols or electrical conditions and other communication conditions between the lines 80, 82, and 64 and the switch 114A so that they can communicate with each other. . Each of the interface units 102A, 104A and 106A has a failure detecting function for detecting an abnormality of a signal transmitted through the digital lines 80, 82 and 64 connected thereto, for example, a loss of clock synchronization and a loss of frame synchronization. When the interface units 102A, 104A, and 106A detect an abnormality in a signal transmitted on these lines, the central processing unit 110A does not select the line on which the abnormality is detected, thereby bypassing the failed line.

The interface units 102A, 104A and 106A are further connected to a central processing unit 110A by a connection line 124A, and a timeout signal 124A is sent from the central processing unit 110A.
When receiving (described later), a system down signal indicating a failure of the other system, ie, the central processing unit 110B of the first system, is sent to the line
It has the function of sending to 80, 86 and 64 respectively. In FIG. 1, the connection lines 124A and 124B conceptually show the connection to the interface units 102A, 104A and 106A by a single line in order to avoid complication of the drawing.

The switch 114A includes an interface unit 102A,
This is a communication path device that performs exchange connection with the trunk lines 80, 82, and 64 via 104A and 106A. The switch 114A is connected to the switch 74 together with the interface units 102A, 104A and 106A.
Of the communication path device. The central processing unit 110A is connected to the switch 114A via a control line 120A.

The central processing unit 110A is a control function unit for controlling the operation of each component included in the 0-system switching unit 74, in particular, the operation of the switch 114A. In this embodiment, the central processing unit 110A is constituted by a computer. In the central processing unit 110A, when a phenomenon in which an operation step becomes abnormal, for example, a runaway occurs, a component to be controlled in the 0-system exchange 74 may not operate as programmed. To resume normal operation, the computer may be initialized. However, if the system is configured such that a call arrives at the exchange 74 including the fault central processing unit 110A from the occurrence of the abnormality until the restart, the calls will be lost.

In this embodiment, in order to minimize such a call loss, a failure monitor 112A is provided as shown. In this embodiment, the failure monitoring unit 112A
A timer is configured to monitor the operation of the central processing unit 110A of the own system 74 via the connection line 122A, and when it detects that it is not operating normally, a signal 94 representing an interrupt to the processing of the other system 76.
Is a central processing unit of the other system in the same switching system 14, that is, a monitoring function unit that sends this to the central processing unit 110B. By monitoring the operation or state of the central processing unit 110A of the own system 74 in this way, the failure monitoring unit 112A detects an abnormal operation of the 0 system switch 74 and notifies the 1 system switch 76 of it.

The fault monitoring unit 112A monitors the arrival of the reset signal 122A from the central processing unit 110A, and generates a timeout signal 94 when it detects that the reset signal 122A does not arrive even after a predetermined time has elapsed. Have been. During normal operation, the central processing unit 110A outputs the reset signal 122A at a time interval shorter than the above-described predetermined time.
Send to 112A. The fault monitoring unit 112A outputs the reset signal 122A
Is reset to the initial value. If the central processing unit 110A is not operating normally, the reset signal 122A is not generated from the central processing unit 110A. If the failure monitoring unit 112A does not receive the reset signal 122A even after a predetermined time has elapsed, the failure monitoring unit 112A generates a timeout signal 94.

More specifically, referring to FIG. 3, in this embodiment, the fault monitoring unit 112A is connected to the central processing unit 110A via a bus 122A. The failure monitoring unit 112A includes a timer circuit 130A. The timer circuit 130A
Includes a counter circuit and a free-running clock generator (both not shown), increments (or decrements) the counter value every predetermined number of clocks, and generates a timeout signal when the counter value reaches a predetermined set value I do. The timeout signal is sent out of the system 0 switch 74 via the signal line 94. The failure monitoring unit 112A is connected to the central processing unit 110B of the first system switch 76 via the signal line 94.

The above-mentioned predetermined value of the timer circuit 130A, that is, when the failure monitoring unit 112A
The time until 94 is generated is set longer than the time interval at which the central processing unit 110A sends the reset signal 122A. Therefore, if the reset signal 122A is received before the count value of the timer circuit 130A reaches the set value, the failure monitoring unit 11
In 2A, the counter value corresponding to the elapsed time is reset to the initial value and returns to the initial state, and the elapsed time is restarted from the time when the reset signal 122A was last received. Therefore, as long as the central processing unit 110A is operating normally, the count value of the timer circuit 130A does not reach the set value.
The failure monitoring unit 112A does not generate the timeout signal 94. If the central processing unit 110A is not operating normally, the reset signal 122A is not generated, and when the count value of the timer circuit 130A reaches the set value, that is, when a predetermined time has elapsed from the initial state, the timer circuit 130A A timeout signal 94 is generated.

Referring to FIG. 4, the interface unit 102A
Is composed of an interface conversion circuit 202 and a control circuit 204 connected as shown. The same applies to the other interface units 104A, 106A, 102B, 104B and 106B. In the interface unit 102A, the central processing unit 11
The signal line 124A from 0A is connected to the control circuit 204. The connection line 96 from the other system 76 is connected to the central processing unit 110A.
Interface units 102A, 104A and 106A directly without using
And the timeout signal 96 may be directly input to the control circuit 204 of the interface units 102A, 104A and 106A.

The interface conversion circuit 202 is a circuit that connects the line 80 to the switch 114A and matches the connection conditions between the switch 114A and the line 80. The control circuit 204
A control signal such as a fault indication signal is transmitted to the line 80 in accordance with the control signal 206 from the controller 80, and a control signal such as a fault indication signal is separated from the signal 80 received from the line 80. It has a function of transmitting and receiving control signals to be given to the 204. These control signals are superimposed on speech signals such as voice and data, ie, main information, or transmitted in a time-division manner in a signal format according to the switching system of the line 80 or the like.

The control circuit 204 is a control function unit for controlling the operation of the interface conversion circuit 202 via the control line 206. Upon receiving the timeout signal 124A from the central processing unit 110A, the control circuit 204 receives the timeout signal 124A,
A fault information signal indicating that the system switch 76 has a fault, that is, a system down signal, is generated, and a fault indication signal is transmitted from the interface conversion circuit 202 to the line 80 via the control line 206. In the 0-system switch 70 of the switching system 12 which is connected to the line 80, the occurrence of a failure in the 1-system switch 76 of the switching system 14 can be known.

In the operating state, for example, when one of the terminal devices 20 is operated to request communication to the terminal device 30, the terminal device 20 originates a call from the line 50 and
Is transmitted to the switching system 40.
When the switching system 40 receives the communication request signal, the switching system 40
60 or 62 is selected, and a communication path is set between the selected trunk line 60 or 62 and the subscriber line 50. For example, trunk line 60
Is selected, the communication request signal 50 from the switching system 40
Is connected to the system 0 switch 70 in the switching system 12 through the trunk line 60.
Sent to If there are no failures in switching systems 12 and 14 and their associated lines, system 0 switch 70 in switching system 12 to system 0 switch 74 in switching system 14
Or exchange system 42 through one of system 1 exchanges 76
To the terminal device 30 for which the connection to the
Incoming call. In this embodiment, the route selection in this redundant configuration is performed according to the load distribution. It goes without saying that this operation is the same when a call is made from the terminal device 30 and the terminal device 20 receives a call.

For example, taking the central processing unit 110A of the 0-system switching system 74 as an example, when this is operating normally, a reset signal 122A is generated at predetermined time intervals, and this is sent to the fault monitoring unit 112A. Since the sending operation is continuing,
At this time interval, the failure monitoring unit 112A is initialized. Therefore, no timeout signal 94 is generated.

Here, for example, if a failure occurs in the control system of the system 0 switch 74 of the switching system 14, this system 0 switch 74
Detects a failure in the failure monitoring circuit 112A and notifies the other system, that is, the 1-system switch 76, of the failure.
Sends a fault indication signal indicating that a fault has occurred in the 0-system switch 74 to the lines 84, 86 and 66 through the interface units 102B, 104B and 106B.

More specifically, if a failure occurs in the central processing unit 110A, the reset signal 122A is not output.
0A times out. Therefore, the time-out signal 94 is sent from the failure monitoring unit 112A to the central processing unit 110B of the first system switch 76.
Sent to The central processing unit 110B of the 1-system switch 76
Upon receiving the timeout signal 94, the interface unit 10
2B, 104B and 106B relay the fault indication signal to the trunk line 82,
Send to 86 and 66.

In the other switching system 12 connected to the trunk lines 82, 86 and 66, when the 0-system exchange 70 and the 1-system exchange 72 receive the fault indication signal, the 0-system exchange 74 of the exchange system 14 cannot be used. In this manner, the trunk 80 and the trunk 80 to the system 0 switch 74 of the switching system 14 are recognized.
82 is excluded from the route selection candidates, and other trunk lines 84 and
Only 86 remains a choice. Thereafter, the system 0 switch 70 of the switching system 12 has only the trunk line 84 to the system 1 switch 76 of the switching system 14, and the system 1 switch 72 has only the trunk line 86 to the system 1 switch 76 of the switching system 14. Use to set the route. That is, the communication request signal received from the switching system 40 by the 0-system switching unit 74 in the switching system 12 is transmitted to the 1-system switching unit 76 in the switching system 14 via the remaining line 84.

This state corresponds to the system 0 switch of the switching system 14.
At 74, the central processing unit 110A is initialized, the operation program is reloaded, and the failure monitoring unit 112A is reset and continued until normal operation is resumed. When the normal operation is restarted, the reset signal 122A is sent again from the central processing unit 110A to the failure monitoring unit 112A at a predetermined cycle.

The 1-system switch 76 of the switching system 14 that has received the communication request signal from the 0-system switch 74 of the switching system 12 sends this communication request signal to the switching system 42 via the trunk line 66. The switching system 42 selects a subscriber line 54 connected to any one of the terminating terminal devices 30 according to the communication request according to the communication request signal, and sets a route.

Thus, from the calling terminal device 20, the subscriber line
50, switching system 40, trunk 60, system 0 switch 70 of switching system 12, trunk 84, system 1 switching 76 of switching system 14,
A communication path to the called terminal device 30 via the trunk line 66, the switching system 42, and the subscriber line 54 is set. That is, the call setup is completed without uselessly accessing the 0-system switch 74 in the switching system 14 in which the failure has occurred, and the communication between the calling terminal device 20 and the called terminal device 30 becomes possible.

In this example, the switching system 42 receives a fault indication signal from the first system switch 76 of the switching system 14 via the trunk line 66. Therefore, the switching system 42 switches the call originating from the terminal device 30 to the switching system 0 of the switching system 14.
It can be redirected to the 1-system switch 76 bypassing the 74.

The switching system in the present invention is not limited to such a circuit switching system, but may be a non-circuit switching system, for example, a packet switching system. In this case, of course, the terminal devices 20 and 30 are packet-type terminals, and the switching systems 12, 14, 40, and 42 have a packet switching function.

Referring to FIG. 5, when a failure occurs in a central processing unit 124A of an exchange, for example, 74, an exchange system 14 according to another embodiment of the present invention is accommodated in the failed exchange 74. It has a self-failure notification function of sending a system down signal through the trunk lines 80, 84 and 64 that are present. For this purpose, in this embodiment, the system 0 switch 74 is used.
The timeout output signal line 94 from the failure monitoring unit 112A of
Instead of being connected to the central processing unit 110B of the 1-system switch 76 as in the embodiment shown in FIG. 1, it is connected to the interface units 102A, 104A and 106A of its own 0-system switch 74. More specifically, as shown in FIG. 6, the signal line 94 from the fault monitoring unit 112A is connected to the control circuit 204 of the interface unit 102A. In the case of this embodiment, the first system switch 76 of the switching system 14 and the switching system 12
The 0-system exchange 70 and the 1-system exchange 72 are similarly constructed.

In the operating state, for example, the switching system
When a failure occurs in the central processing unit 110A of the 0-system switch 74 in 14, the failure monitoring unit 112A generates the timeout signal 94 indicating this failure as described above,
It is sent to the interface units 102A, 104A and 106A at 74. Thus, for example, in the interface unit 102A, the control circuit 204 controls the interface conversion circuit 202 and sends a fault indication signal to the line 80 to the system 0 switch 70 of the switching system 12. Similarly, in the other interface units 104A and 106A, the 1-system exchange 72 of the exchange system 12 respectively.
Then, a failure indication signal is transmitted to the switching system 42. Thus, in this embodiment, the central processing unit 110A
The own system switch is operated by the system 0 switch 74 itself which has failed.
The occurrence of the 74 failure can be notified to the other switching systems 12 and 42.

The present invention is not limited to the digital communication system as described above, but can be applied to analog communication. For the sake of simplicity, for example, if the line 80 is a two-wire analog line, as shown in FIG.
102A is the same as the interface unit described with reference to FIG. 6 except that it includes switch units 210 and 212, and the configuration of the interface conversion circuit 202 and control circuit 204 related thereto is different.

The control circuit 204 includes control lines 230 and 2
They are connected to the switches 210 and 212 by 32, respectively, and have a function of controlling the switches 210 and 212 in response to the timeout signal 94 from the fault monitor 112A.

In the switch section 210, two contacts 220 and 222 are inserted as shown in two lines of the line 80 to the interface conversion circuit 202, and both contacts 220 and 222 are normally closed, that is, the connection state shown in FIG. It is in. The switch section 212 has a contact 224 connected as shown so that the line 80 to the interface conversion circuit 202 is short-circuited on the outside of the switch section 210 with two wires, and the contact 224 is always open.
That is, it is in the connection state shown in the figure. Switch section 210 and
212 may be a mechanical switch or a semiconductor switch. When the multiplex communication network 10 is an analog circuit network, the other interface units 104A and 106A, and each interface unit in the other exchanges 76, 70 and 72 are also interface units.
The configuration may be substantially the same as 102A.

In the interface circuit 102A shown in FIG. 7, for example, when the fault monitoring unit 112A of the system 0 switch 70 of the switching system 12 detects a fault in the central processing unit 110A and sends a timeout signal 94 to the control circuit 204, Circuit 204
By driving the switch sections 210 and 212, the former contact 220
And 222 are opened, and the latter contact 224 is closed. This closes the loop on line 80. Therefore, when the line 0 switch 70 of the opposite switching system 12 activates the line 80, by detecting the busy state in the loop Heiseki, it is possible to know the occurrence of the failure of the line 0 switch 74 of the switching system 14. In the embodiment shown in FIG. 7, the line 80 is a two-wire system, but it goes without saying that the present invention can be similarly applied to a four-wire system.

[0045]

As described above, according to the present invention, in a multiplexed communication network for setting a communication path between redundantly configured switching systems, a failure monitoring unit monitors the operation of a central processing unit, and one of the switching units. When a failure occurs in the central processing unit of the system, the occurrence of the failure is notified to the other switching system via a line, and a communication path is established via the other switching system, thereby restarting from the failure. The call loss during processing can be reduced.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of a switching system according to the present invention.

FIG. 2 is a relay system diagram showing an embodiment of a multiplex communication network according to the present invention.

FIG. 3 is a functional block diagram illustrating a configuration example of a central processing unit and a failure monitoring unit in the embodiment illustrated in FIG. 1;

FIG. 4 is a functional block diagram illustrating a configuration example of an interface unit in the embodiment.

FIG. 5 is a functional block diagram similar to FIG. 1, showing another embodiment of the switching system according to the present invention.

FIG. 6 is a functional block diagram showing a configuration example of an interface unit in the embodiment shown in FIG. 5;

FIG. 7 is a functional block diagram showing another configuration example of the interface unit.

[Explanation of symbols]

10 Multiplexed communication network 12, 14, 40, 42 Switching system 20, 30 Terminal device 102A, 102B, 104A, 104B, 106A, 106B Interface unit 114A, 114B Switch 110A, 110B Central processing unit 112A, 112B Fault monitoring unit

Claims (12)

[Claims] A first and a second line going to a first route, and a third and a fourth line going to a second route different from the first route are accommodated in the first and third lines. In a multiplexed communication network including a first switch for setting a communication path between the first and second lines and a second switch for setting a communication path between the second and fourth lines, the first switch includes: A first communication path means accommodating the first and third lines, and a first communication path means for setting a communication path between the first and third lines; a first communication path means for controlling the first communication path means; A first control means for setting a communication path between the first and third lines, and an operation of the first control means is monitored, and an abnormal operation of the first control means is detected. Output the first
A second communication path means for accommodating the second and fourth lines and setting up a communication path between the second and fourth lines; Control means for controlling the communication path means and setting a communication path between the second and fourth lines in the second communication path means, the communication network comprising: A first connection unit for connecting the failure information signal from the first communication unit to the second control unit. The second control unit receives the failure information signal from the first failure monitoring unit, and the second communication path unit And transmitting a signal indicating that the first switch is faulty to the second and fourth lines. 2. The system of claim 1, wherein the second switch further monitors operation of the second control means,
A second fault monitoring means for outputting a fault information signal when an abnormal operation of the second control means is detected, and the communication network further includes a fault information signal from the second fault monitoring means. A second connection unit connected to the control unit, wherein the first control unit, upon receiving the failure information signal from the second failure monitoring unit, controls the first communication path unit to perform the first and third connection operations. A failure notification system for transmitting a signal indicating that the second exchange has a failure to the line. 3. The system according to claim 2, wherein the first and second control means each generate a signal at a predetermined cycle when operating normally, and the first and second failure monitoring means are provided. Each of which includes timer means for generating the fault information signal when the signal is not received for a predetermined period longer than the predetermined cycle. 4. The system according to claim 2, wherein each of the first and second control means, when receiving the signal indicating the fault, does not perform the connection setting for the route receiving the signal. A failure notification system characterized by the following. 5. A communication path means for accommodating a plurality of lines, setting a communication path between the plurality of lines, controlling the communication path means, and communicating between the plurality of lines in the communication path means. Control means for setting a path; and fault monitoring means for monitoring the operation of the control means and outputting a fault information signal when an abnormal operation of the control means is detected. An exchange connected to monitoring means, and transmitting a fault indication signal to the plurality of lines upon receiving the fault information signal from the fault monitoring means. 6. The exchange according to claim 5, wherein said control means generates a signal at a predetermined cycle when operating normally, and said fault monitoring means operates for a predetermined period longer than said predetermined cycle. And a timer means for generating the failure information signal when the signal is not received. 7. A first and a second line going to a first route, a third and a fourth line going to a second route different from the first route are accommodated, and the first and third lines are accommodated. In a multiplexed communication network including a first switch for setting a communication path between the first and second lines and a second switch for setting a communication path between the second and fourth lines, the first switch includes: A first communication path means accommodating the first and third lines, and a first communication path means for setting a communication path between the first and third lines; a first communication path means for controlling the first communication path means; A first control means for setting a communication path between the first and third lines, and an operation of the first control means is monitored, and an abnormal operation of the first control means is detected. Output the first
First communication path means is connected to the first failure monitoring means,
Upon receiving the fault information signal from the first fault monitoring means,
A fault reporting system for a multiplex communication network, wherein a fault indication signal is transmitted to first and third lines. 8. The system according to claim 7, wherein the second switchboard accommodates the second and fourth lines, and sets up a communication path between the second and fourth lines. Path means; second control means for controlling the second communication path means; and setting a communication path between the second and fourth lines in the second communication path means; and operation of the second control means. Is monitored, and when an abnormal operation of the second control means is detected, a second fault information signal is output.
The second communication path means is connected to the second fault monitoring means,
Upon receiving the fault information signal from the second fault monitoring means,
A fault reporting system for transmitting a fault indication signal to second and fourth lines. 9. The system according to claim 8, wherein the first to fourth lines are digital lines, and the fault indication signal is included in a control signal transmitted through the digital line. Failure reporting system. 10. The system according to claim 8, wherein
The first to fourth lines are analog lines, and the first and second communication path means include means for forming a loop in the analog line, and the fault indication signal is transmitted by forming the loop. A failure notification system characterized by the following. 11. The system according to claim 8, wherein
The first and second control means each generate a signal at a predetermined cycle when operating normally, and the first and second fault monitoring means each generate a signal during a predetermined period longer than the predetermined cycle. A failure notification system comprising timer means for generating the failure information signal when no signal is received. 12. The system according to claim 8, wherein
A failure notification system, wherein each of the first and second control means, upon receiving the failure indication signal, does not perform connection setting for a route receiving the failure indication signal.