JP2001298459A - System changeover device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system changeover device that can prevent both an active system and a stand-by system from falling in a system-down, even in the case that the stand-by system is faulty when the active system is switched into the stand-by system. SOLUTION: A master bus controller 100 of the active system and a master bus controller 200 of the stand-by system monitor operations of slave bus controllers 130-160 and 230-260 connected respectively to the controllers 100, 200. When any of the slave bus controllers 130-160 is faulty and the master bus controller 100 of the active system is going to select the stand-by system and any of the slave bus controllers 230-260 of the stand-by system is faulty, the master bus controller 100 forcibly turns off a slave error signal 101, to inhibit switching to the stand-by system and to continue the operation by the active system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system switching device and, more particularly, to an active system slave bus controller.
The present invention relates to a system switching device for preventing a system failure by switching to a standby slave bus controller by a master bus controller when a failure occurs in a bus controller.

[0002]

2. Description of the Related Art Conventionally, an apparatus for relaying an audio signal has two buses, and if one of the bus systems fails, the entire system is switched.
That is, the system is duplicated by the active master bus controller that controls the active slave bus controller and the standby master bus controller that controls the standby slave bus controller, so that data loss due to a failure does not occur. As shown in FIG. When a failure occurs in the active slave bus controller, the active slave bus controller is switched to the standby slave bus controller. For example, the active system and the standby system each have four slave bus controllers (the active system is # 10, # 11,
# 12, # 13, standby systems are # 20, # 21, # 22, #
23), when a failure occurs in any one of the active slave bus controllers # 10 to # 13, a failure occurs instead of switching only the failed one to the standby system. As a result, all of the active slave bus controllers # 10 to # 13 are replaced with all of the standby slave bus controllers # 20 to # 23.

[0003]

However, according to the conventional system switching device, when a failure occurs in the active slave bus controller and the system is switched to the standby system, one of the standby system slave bus controllers fails. Has occurred, the standby master bus controller notifies the active system of the occurrence of the fault. For this reason, switching to the standby system is not performed, and a state in which a slave error signal is output in both the active system and the standby system occurs, and both the active system and the standby system may go down. Such a situation becomes a problem in a highly public system.

An object of the present invention is to provide a system capable of preventing both the active system and the standby system from being shut down when the active system is switched to the standby system, even if the standby system has a fault. A switching device is provided.

[0005]

According to the present invention, in order to achieve the above object, an active master bus controller and a standby master bus controller are mutually connected, and each of the master bus controllers has a plurality of slave buses. A system switching device that includes a bus controller and switches from the active master bus controller to the standby slave bus controller by the active and standby master bus controllers when a failure occurs in the active slave bus controller; In switching to the standby system slave bus controller, when a failure occurs in the standby system slave bus controller, switching to the standby system is prohibited and the operation of the active system slave bus controller is continued. Having control means for causing Providing system switching device according to symptoms.

According to this configuration, when a failure occurs in the active slave bus controller and a failure occurs in the standby slave bus controller, the control means switches from the active system to the standby system. The system is not switched and the operation is maintained as it is. This can prevent both the active system and the standby system from going down.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a system switching device according to the present invention. The system switching device includes a master bus controller 100 as an active system, a master bus controller 200 as a standby system, a slave bus controller 130 whose operation state is monitored by the master bus controller 100,
140, 150, 160, master bus controller 2
The slave bus controllers 230, 240, 250, and 260 whose operating states are monitored by 00 are configured. The master bus controller 100 and the master bus controller 200 are mutually connected.

The master bus controller 100 includes a slave bus controller status monitoring unit 110 and a master bus controller status monitoring control unit 120. The slave bus controller status monitoring unit 110 receives slave fault signals 112 from the slave bus controllers 130 to 160. Similarly, the slave bus controller includes a slave bus controller status monitoring unit 210 and a master bus controller status monitoring control unit 220. The slave bus controller status monitoring unit 210 receives a slave fault signal 212 output from the slave bus controllers 230 to 260. Is entered. The slave bus controller status monitoring unit 110 turns on the active slave status signal 111 sent to the slave bus controller status monitoring unit 210, and further sets the slave error signal 10 sent to the master bus controller status monitoring and control unit 120.
Turn 1 ON. In response to this, the master bus controller status monitoring control unit 120 turns on the system switching signal 121. The system switching signal 121 is received by the master bus controller status monitoring controller 220, and the master bus controller 100 executes switching to the standby system.

FIG. 2 shows the processing timing of the system switching device of FIG. With reference to FIG. 2, the operation of the system switching device having the configuration of FIG. 1 will be described below. When normal, each slave fault signal 1 from the slave bus controllers 130 to 160
Reference numeral 12 is OFF. When a failure occurs in any of the slave bus controllers 130 to 160 (S1)
1), the slave fault signal 112 of the faulty slave bus controller is turned on (S12). At this time, if the standby slave status signal 211 output from the slave bus controller status monitoring unit 210 is OFF, the slave bus controller status monitoring unit 110 of the master bus controller 100 outputs the slave error signal 1
01 is turned ON (S13), and the master bus controller status monitoring and control unit 120 receiving this turns on the system switching signal 121.
Is generated (S14), switching from the active system to the standby system is performed (S17).

However, the master bus controller 200
Any one of the slave bus controllers 230 to 260
In the event that a failure has occurred (S15) and the slave failure signal 212 of the slave bus controller is ON, the master bus controller status monitoring unit 210 of the master bus controller 200 sends it to the slave bus controller status monitoring unit 110. The slave status signal 211 of the standby system is turned on (S16). Accordingly, the slave bus controller status monitoring unit 110 determines the status of the standby system, and forcibly turns off the slave error signal 101 (S18). O of this slave error signal 101
The FF does not switch from the active system to the standby system (S19), and the operation by the active system slave bus controller is continued (S20). At this time, the system of the slave bus controller in which the failure in the active system has stopped operating, but the system of the normally operating slave bus controller in the active system can be continuously used. Therefore, even if a partial down occurs, a situation in which the entire system goes down is avoided.

FIG. 3 shows an application example of the system switching device of the present invention. Here, an audio signal relay device is taken as an application object. The system switching device 300 according to the present invention is incorporated in the bus system of the relay device. Relay device 500
Are provided between a higher-level device 400 and a lower-level device (not shown), and include upper-level shelves 510, # 0 shelves 520, and # 1.
The shelf 530 has a three-shelf configuration. The upper device 400 is, for example, an exchange (base station) in a network or a circuit system, and the lower device is a portable terminal or the like. Upper shelf 510 is line interface 5
11 and the # 0 shelf 520 includes a line relay circuit 521.
# 1 shelf 530 includes a line relay circuit 5
31 to 533. These line relay circuits include:
For example, each channel of a communication line is connected. The system switching device 300 includes an upper shelf 510 and a # 0 shelf 52.
0, and are shared by the # 1 shelf 530, but operate on the active system (master bus controller 100).
Or, one of the standby systems (master bus controller 200), and the other is on standby.

A signal from the host device 400 is sent to the master bus controller by the line interface 511 as one signal.
00,200. Since the master and slave bus systems have a redundant configuration, a circuit for switching from the active system to the standby system is provided. The master bus controller 100 is connected to the slave bus controllers 130 and 140 of the # 0 shelf 520, and the master bus controller 200 is connected to the slave bus controllers 230 and 240 of the # 1 shelf 530. Signals from the master bus controllers 100 and 200 are sent from the slave bus controllers 130, 140, 230 and 240 to the line relay circuits 521 to 523 and 531 to 533 and relayed to lower-level devices.

Next, the operation of the system shown in FIG. 3 will be described with reference to FIG. Master bus controller 10
0 constantly monitors the state of the slave bus controllers 130 and 14. When a failure occurs in any of the slave bus controllers 130 and 140 due to an external factor,
Slave fault signal 11 of the slave bus controller
2 is turned ON, and a state change is transmitted to the master bus controller 100. The slave fault signal 112 is received by the slave bus controller status monitor 110, and the slave bus controller status monitor 110 turns on the slave status signal 111 of the active system, and further sets the slave error signal 10
Turn 1 ON. In response to the slave error signal 101 being turned on, the master bus controller status monitoring control unit 120 turns on the switching signal 121. As a result, the master bus controller is switched from the active system to the standby system.

When switching to the standby system, if any of the standby slave bus controllers 230 and 240 has a fault, the master bus controller 200 causes the master bus controller status monitoring unit 210 to output a standby slave status signal. 211 is turned on to notify the slave bus controller status monitoring unit 110 of the master bus controller 100 of the prohibition of switching. In response to this notification, the slave bus controller state monitoring unit 110 forcibly turns off the slave error signal 101 so as not to switch to the standby system so that the slave error signal 101 does not turn on. In addition, as a post-process, the administrator performs recovery work (inspection, repair, replacement, and the like) of the slave bus controller in which the failures in the active system and the standby system have occurred.

In the configuration as shown in FIG. 3, it is unlikely that two slave bus controllers of the active system and the standby system will fail at the same time. However, when the power supply of the shelf is cut off, two slave bus controllers fail simultaneously. In such a case,
By including the switching prohibition device 300 according to the present invention, other shelves can be in operation.
For example, when a failure occurs in the slave bus controller 130 and the master bus controllers 100 and 200 attempt to switch from the active slave bus controllers 130 and 140 to the standby slave bus controllers 230 and 240, the slave bus controller 23
If the fault has occurred in the slave bus controller 140 of the active system, the switching to the spare slave bus controller 230 or 240 is not performed.
Only done by. Therefore, # 0 shelf 520
Goes down, but the # 1 shelf 530 stays down.

FIG. 4 shows the details of the configuration of the slave bus controller status monitor 110 of FIG. Here, only the active system side is illustrated, but the configuration of the standby slave bus controller status monitoring unit 210 is the same. NAND gates 301, 302, 30 whose output terminals are commonly connected
3,304, one open collector (Open Collecto
r, hereinafter referred to as O / C) includes a slave fault signal 112
, Slave resistors 305, 306, 307, 308 are connected between each of these input lines and the ground. N
Each of the other O / Cs of the AND gates 301 to 304 is pulled up to the power supply Vcc. N
A resistor 313 is connected between the output terminals of the AND gates 301 to 304 and the ground. Further, an inverter 314 and a buffer 315 are connected to output terminals of the NAND gates 301 to 304. Inverter 314
Is connected to one input terminal of the NAND gate 316, and the other input terminal of the NAND gate 316 is connected to the output terminal of the buffer 317. NAN
The output signal of the D gate 316 is the slave error signal 10
1 is output. Inverter 314, NAND gate 3
16 and the buffer 317 form a wired OR circuit. The buffer 317 is supplied with the standby slave state signal 211 and its output signal becomes the active slave state signal 111. Note that the NAND gate 3
The reason why the pull-down processing is performed in 01 to 304 is that it can be regarded as a failure even at the time of reset and when not mounted.

Next, the operation of the system switching device of the present invention will be described with reference to FIGS. The slave bus controllers 130 to 160 are normally at the “L” level, and go into the “H” level (high-impedance state) when a failure occurs. For example, slave bus controller 1
When the failure 40 is caused by an external factor, the slave failure signal # 1 becomes "H" level. Therefore, NA
Since one input terminal of the ND gate 302 is at “H” level and the other input terminal is also pulled up by the resistor 309 to be at “H” level, the output terminal of the NAND gate 302 is at “L” level. This signal becomes an "L" level slave signal 111 through the buffer 315, and becomes an active slave status signal 111 for transmitting a fault in the active system to the standby system. Further, the output signal of NAND gate 302 is inverted by inverter 314 to attain an "H" level.

At this time, the slave status signal 211 of the standby system is input to the buffer 317 from the slave bus controller status monitor 210. If all the standby slave bus controllers 230 to 260 are in a normal state, the standby slave state signal 211 is at "H" level, indicating "normal standby system". Therefore, NA
Both inputs of the ND gate 316 become “H” level,
The output signal of the slave error signal 101 is “L”.
Become a level. Upon receiving this signal from the slave bus controller status monitoring unit 110, the master bus controller status monitoring control unit 120 determines that the active slave has a fault, turns on the system switching signal 121, and switches to the standby system.

On the other hand, when any one of the slave bus controllers 230 to 260 in the standby system enters the fault state, the slave status signal 211 in the standby system becomes "L" level, indicating that a fault has occurred in the standby system. If the standby system slave state signal 211 is at “L” level, the inverter 314
Irrespective of the level state of the output signal, the output of the NAND gate 316, that is, the slave error signal 101 becomes "H" level, and the failure of the active slave bus controller is masked. Thus, even if a failure occurs in the active slave bus controller, if any of the standby slave bus controllers fails,
Switching to the standby system is not performed.

[0020]

As described above, according to the system switching device of the present invention, when a failure occurs in the active slave bus controller and a failure occurs in the standby slave bus controller, control is performed. Since the means does not switch from the active system to the standby system, even when a failure occurs in both the active system and the standby system, a system down can be prevented. In addition, the control can be performed only by the master bus controller without taking care of the host device, so that the system is not enlarged.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system switching device according to the present invention.

FIG. 2 is an explanatory diagram showing processing timing of the system switching device of FIG. 1;

FIG. 3 is a block diagram showing an application example of the system switching device of the present invention.

FIG. 4 is a circuit diagram showing details of a configuration of a slave bus controller status monitoring unit of FIG. 1;

[Explanation of symbols]

100, 200 Master bus controller 101, 201 Slave error signal 110, 210 Slave bus controller status monitoring unit 112, 212 Slave failure signal 120, 220 Master bus controller status monitoring control unit 121, 221 System switching signal 130, 140, 150, 160 Slave bus controller 230, 240, 250, 260 Slave bus controller 300 System switching device 301-304, 316 NAND gate 314 Inverter 315, 317 Buffer

Claims (4)

[Claims] An active master bus controller and a standby master bus controller are interconnected, each of the master bus controllers includes a plurality of slave bus controllers, and a failure occurs in the active slave bus controller. In the system switching device for switching from the active master bus controller to the standby slave bus controller by the active and standby master bus controllers, when switching to the standby slave bus controller, And a control unit for prohibiting switching to the standby system and continuing the operation of the working slave bus controller when a failure occurs in the slave bus controller. 2. The slave bus controller status monitoring unit that generates a slave status signal when a slave fault signal indicating that a fault has occurred is input from the slave bus controller, the master bus controller of the active system and the master bus controller of the standby system; 2. The system switching device according to claim 1, further comprising a master bus controller status monitoring control unit that transmits a system switching signal to a partner system based on a slave status signal from the bus controller status monitoring unit. 3. The slave bus controller status monitor includes: a NAND gate that generates the active slave status signal using the slave fault signal as an input condition; an output of the NAND gate and the standby slave status signal. 3. The system switching device according to claim 2, further comprising a wired OR circuit that generates a slave error signal by taking the logic of (1). 4. The system switching device according to claim 2, wherein said NAND gate is of an open collector type.