JPH04333162A - System switching system - Google Patents

Abstract

PURPOSE:To hold a working CPU as an ACT (working) system before a system switching device has a fault even if the CPU and then the system switching device have the faults. CONSTITUTION:A working state information transmission circuit 70 of a system switching device 10 sends the system switching device operating state information 80 showing the working state of its own device to the CPU 20 and 30. At the same time, a system switch signal transmission circuit 60 sends the system switch signals 40 and 50 of both an ACT and STBY(stand-by) systems to both CPU 20 and 30 respectively. The system deciding circuits 140 and 190 receive the information 80 from the device 10 and recognizes the normalcy of the information 80. Thus the circuits 140 and 190 decide whether their own systems are identical with the ACT or STBY system based on the system recognizing signals 110 and 160 and then transmit the ACT signals 120 and 170. The system information transmission circuits 150 and 180 latch the information on the signal 120 or 170 and send this latched information to the circuits 140 and 190 of the distant CPU 20 and 30 as the other system state signals 90 and 100.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system switching system for electronic exchanges, and more particularly to a system switching system when a system is redundantly controlled by two central processing units.

0002

2. Description of the Related Art Conventionally, in this type of system switching system, as shown in FIG. 2, a system switching signal sending circuit 60 of a system switching device 10 sends system switching signals 40,
Send 50. At this time, if the central processing unit 20 is currently in use (hereinafter referred to as ACT system), it sends the "L" level to the system switching signal 40 and the "H" level to the system switching signal 50, and if the central processing unit 30 is in the ACT system, In this case, the system switching signal 40 is “H”.
” level, and the “L” level is sent to the system switching signal 50.

The central processing units 20, 30 receive the system switching signals 40, 50 and recognize whether they are the ACT system or the standby system (hereinafter referred to as STBY system). Also, system switching device 1
0 has failed and there is no system switching device in the process of dealing with it, the system switching signals 40 and 50 both go to the "H" level due to the pull-up resistors, and both the central processing units 20 and 30 recognize the same system. Therefore, one of them was fixed to the ACT system (for example, the central processing unit 20 was fixed to the ACT system).

0004

[Problems to be Solved by the Invention] In the conventional system switching system described above, when the system switching device 10 is out of order, one of the central processing units (for example, the central processing unit 20) becomes the ACT system and controls the system. For example, if a failure occurs in the central processing unit 20, the system switching device 1
0 switches the central processing unit 30 to the ACT system,
When this central processing unit 30 is controlling the system,
When a failure occurs in the system switching device 10, the central processing unit 30
Although the central processing unit 20 side is forcibly switched to the ACT system even though the system is operating normally, there is a drawback that the system cannot be controlled because the central processing unit 20 is out of order.

An object of the present invention is to provide a system switching system that maintains the central processing unit that was operating as an ACT system before the failure of the system switching device even if a failure occurs in the system switching device of one of the central processing units. Our goal is to provide the following.

[0006]

[Means for Solving the Problems] The system switching method of the present invention is as follows:
The central processing units are duplicated, and one system switching device sends a system switching signal indicating the system information of the active system and the standby system to the two central processing units, and this system switching signal causes the two systems to switch between the two central processing units.
In an electronic exchange in which system switching of two central processing units is performed, the system switching device has an operating state information sending circuit that sends system switching device operating state information indicating the operating state of the own device to the two central processing units. Each of the two central processing units has a system information sending circuit that sends out a system status signal indicating the system information of the system switching device to each other, and a system switching device operating state information that indicates the system switching device. and a system determination circuit that selects the system switching signal from the CPU and the other system status signal between the two central processing units, and performs system switching control of the system based on the selected information.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The central processing unit 20 includes a system recognition unit 130 that detects a system switching signal from the switching device 10, a system determination unit 140 that detects and determines whether it is an ACT system or a STBY system from the system switching signal, and a system determination unit 140 that detects the system switching signal and determines whether it is an ACT system or a STBY system, The central processing unit 30 also includes a system recognition section 200, a system determination section 190, and a system information transmission section 180.

The system switching device 10 includes a system switching signal sending circuit 60 that sends out system switching signals for the ACT system and STBY system, and an operating state information sending circuit 70 that sends out operating state information of the system switching device 10. ing.

The system switching device 10 includes a system switching signal sending circuit 6
0 to the system recognition circuit 130 of the central processing units 20 and 30
and sends system switching signals 40 and 50 to 200. The system recognition units 130 and 200 perform ACT from these two signals.
, STBY information is detected and the system recognition signals 110 and 16 are detected.
0 to the system determination circuits 140 and 190, respectively.

The system determination circuits 140 and 190 receive the system switching device operation information 80 sent from the operating state information sending circuit 70 of the system switching device 10, and if they recognize normal operation, they issue system switching signals 40 and 50. ACT identified from,
The STBY information is sent as an ACT signal 120 or 170. When an abnormality in operation is recognized, it receives other system status signals 90 and 100 between the central processing units 20 and 30, determines whether the own system is an ACT system or a STBY system, and sends it as an ACT signal 120 or 170. .

This ACT signal 120 or 170 becomes system information for the central processing units 20 and 30 and is sent to system information sending circuits 150 and 180. The system information sending circuits 150 and 180 latch the information of the ACT signal 120 or 170 along with the change, and send it to the system determination circuits 140 and 190 of the other system central processing unit as the other system status signal 90 or 100 between the central processing units. . With such a configuration, even if a failure occurs in the system switching device 10 from a state where the central processing unit 20 is out of order and the central processing unit 30 is operating as an ACT system, the central processing units 20 and 30 If either of these is normal, the system determination circuits 140 and 190 of each central processing unit select the normal central processing unit (central processing unit 30 in the above example) as the ACT system, thereby making system control possible.

[0013]

As explained above, the present invention allows the system switching device 10 to send the operating state information of the system switching device 10 to the central processing units 20 and 30, and also allows the system switching device 10 to transmit its own system information between the central processing units 20 and 30. A failure occurs in the central processing unit 20 as the central processing unit mutually sends other system status information indicating whether the system is currently an ACT system or a STBY system to the other system central processing unit, and the system switching device 10 causes the central processing unit 30 to is an ACT system,
Even if a failure occurs in the system switching device 10 while controlling the system, the normal central processing unit 30
Since the system is controlled while maintaining the CT system, it is possible to prevent the central processing unit 20 from becoming an ACT system and unable to control the system, thereby improving the reliability of the system.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a system switching system of the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional system switching system.

[Explanation of symbols]

10 System switching device 20, 30 Central processing unit 40, 50 System switching signal 60 System switching signal sending circuit 70 Operation status information sending circuit 80 System switching device operation information 90,100 Other system status signal 110,160 System recognition signal 120,170 ACT signal 130,200 system recognition circuit 140, 190 System determination circuit

Claims (1)

[Claims] Claim 1: The central processing units are duplicated, and one system switching device sends a system switching signal indicating system information of the active system and standby system to the two central processing units, and by this system switching signal, In the electronic switching system in which system switching of the two central processing units is performed, the system switching device includes an operating state information sending circuit that sends system switching device operating state information indicating the operating state of the own device to the two central processing units. Each of the two central processing units has a system information sending circuit that sends out a system status signal indicating the system information of the system switching device to each other, and a system switching device operating state information. A system characterized by comprising a system determination circuit that selects the system switching signal from the switching device and the other system status signal between the two central processing units, and performs system switching control of the system based on the selected information. Switching method.