Primary and secondary switching device, and switching method using the same

Abstract

The invention relates to a main / backup switching device and a method for carrying out main / backup switching by using the device; the device comprises a backboard and a reciprocal main / backup structure, a component, a first single plate and a second single plate with the completely same logic circuit; the first single plate is provided with a programmable logic device, a central processing unit and a peripheral circuit, intercommunication between the programmable logic device and the central processing unit is realized by a local bus; the input signals of the programmable logic device comprise: MS_IN, CL_IN, MS_HAND, SYS_DEF and CPU_WDI; the output signals comprise: MS_OUT and CL_OUT; the MS_OUT and CL_OUT output by the first single plate are respectively used as the MS_IN and CL_IN of the second single plate after passing through the backboard so as to be input into the second single plate; the MS_OUT and CL_OUT output by the second single plate are respectively used as the MS_IN and CL_IN of the first single plate after passing through the backboard so as to be input into the first single plate. The technical proposal of the invention occupies less backboard interconnection signals and reliably realizes the main / backup switching.

Description

technical field [0001] The invention relates to an active-standby switching device and a method for using the device to perform active-standby switching. Background technique [0002] Communication network system equipment has very high reliability requirements. In order to improve system reliability, the main and standby hot backup working mode is usually adopted for key single boards. The main board interface signal output is enabled in the system, that is, works online in real time; while the standby board interface signal output is disabled in the system. The interface signals of the two boards are multiplexed together on the back board. When the main board fails, the system should be able to switch automatically to ensure the reliability of the system. [0003] The existing master and backup technologies are as follows: [0004] 1. Use the RS trigger to realize simple interlocking of the hardware master and backup states. When one party initiates the master and slave ...

AI Technical Summary

Problems solved by technology

The problem is that when the single board is plugged in or there is external interference, it is easy to cause abnormal master-standby switchover or even master-standby competition to cause infinite oscillation, thus causing system failure

The problem is that the sampling frequency of the unbalanced filter is determined according to the slot information of the board. When the board is plugged in or there is interference on the main and standby signals, the final decision on who is the master is completely determined by the slot information. It may cause the original main board to become a backup, resulting in abnormal switching;

[0005] 2. Patent No. 99229246.8 is a patent titled "A Switching Method of Main and Standby Boards of Electronic Communication System". If the switch is ready, the master-standby switchover process can be initiated. The master-standby switchover at this time may cause the system to fall into a fault state.

Moreover, during the process of unplugging and inserting a single board, the presence signal of the opposite board may fall off before the active / standby state pin / be contacted after the active / standby state pin, causing the unplugged / inserted single board to mistakenly believe that the state of the opposite board is abnormal, and the Set it as active, due to the interlock mechanism of the active and standby states, the original active single board may become the standby at this time, causing the entire system to fail

[0006] 3. In order to solve the impact of plugging and unplugging the standby board on the main board, some master and backup technologies adopt the master lock method. If a fault occurs, the active state will be locked. For example, the patent No. 01121975.0 is entitled "Active-standby circuit switching equipment and its method", which can ensure that the active-standby relationship will not be abnormal during the normal unplugging process. However, in If the boards are not tightly inserted, loose during work, or interference signals appear on the backboard, it is likely that both boards will enter the active state. Or reset the single board, the two single boards will maintain the dual-master state, which may cause permanent damage to the device

[0007] 4. In order to achieve master-standby switchover without abnormality, the patent No. 01130715.3 titled "master-standby switchover control circuit and implementation method" implements a method of master-standby state control through a serial command interface. The implementation is more complicated, and all operations need to be controlled by software. Once the software of the main single board fails, the system may be interrupted for a long time

Patent No. 98118143.0 The patent titled "Active / Standby Switching Device" proposes to determine the active and standby boards through the ID signal set on the motherboard. However, when a single board fails, it cannot autonomously control the main board Switching to standby, and at the same time another single board is immediately switched from standby to active, which will cause system interruption

[0008] 5. In order to improve the reliability of the system, the patent application No. 200310111916 titled "A Master-Standby Switchover Control Method for Communication Equipment" proposes that the standby board resets the master board or the backup board initiates master-standby switchover function, but the reset protection work is not done enough, and abnormal active / standby switchover and active single board reset may occur when the board is unplugged or disturbed

With the improvement of board integration, backplane wiring resources are becoming more and more precious, especially the boards that adopt the active / standby mechanism are mostly in the control and switching centers, and this problem becomes more prominent. At the same time, too many interfaces Signal makes hardware less reliable

Images