JP3242550B2 - Method and apparatus for controlling switching of a system of a duplexed communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching control method for a system in a duplex communication system and a switching control device for switching the system.

[0002]

2. Description of the Related Art In a transmission apparatus connected to a communication line, for example, an optical multiplex transmission apparatus connected to an optical transmission line, lines and circuits in the transmission apparatus are duplicated in order to improve the reliability of the communication system. I have. In a duplicated system,
It is necessary to constantly monitor the occurrence of a failure and, when a failure in the active system is detected, immediately switch to the standby system to protect the transmission information.

[0003] As a switching control process of a transmission device, there is a process for supporting a maintenance function such as a manual switching of a system for maintenance work, in addition to a process for relieving a failure.

FIG. 6 is a flowchart of a switching control process based on a conventional switching control method. In this switching control process, the execution cycle of the entire process is managed by a timer interrupt every 10 ms, and the timer interrupt every 10 ms is used as a clock of various timers necessary for the switching control. The switching control process is executed by a switching control unit in the transmission device.

First, it is determined whether or not a timer interrupt with a period of 10 ms has occurred (S11 in FIG. 5). If no timer interrupt is detected in this determination, the timer interrupt detection process is repeated.

On the other hand, when a timer interrupt is detected, the flow advances to step S12 to determine whether or not an interrupt has occurred due to setting of the operating environment and updating of control information. The system switching control process supports switching corresponding to various operating environments, artificial system switching for maintenance work, and the like. The setting information / control information that determines the switching conditions includes faults. The notification is sent from the system monitoring device to be monitored, and at that time, an interrupt for updating the setting information / control information is generated.

When an interrupt for updating the setting information / control information of the operating environment occurs (S12, YE
S), setting / control information of the operating environment is acquired (S1)
3). Then, the presence or absence of a failure in the line or the circuit of the transmission device is detected (S14). The detection of a failure is performed by a failure detection unit in the transmission device, and failure information detected by the failure detection unit is notified to the switching control unit.

Next, an appropriate switching condition is determined by comprehensively judging the presence / absence of a fault, a switching request for maintenance, and setting information / control information of the operating environment (S15), and the system is switched based on the switching condition. Perform (S16). Further, various timers are started / stopped, counted up, and counted down (S17). Next, a maintenance management function for collecting maintenance information, line quality information, and the like is controlled (S18). Then, the system switching status, maintenance management information, and the like in the event of a failure are edited and notified to the system monitoring device (S1
9).

[0009]

As the transmission apparatus handles a large amount of information at a high speed, it is required that the system can be normally restored in a short time when a failure occurs.

On the other hand, in the above-described conventional switching control method, when a failure is detected, switching to the standby system and normal operation of the system are performed in a single cycle for repairing the failure, providing maintenance management, and providing other service functions. Therefore, there is a problem that the processing time of the entire switching control process becomes longer, and it takes time to recover from the failure. Also,
Since the start timing of the switching control process is determined, even if the process is completed, the process is not executed until the next start timing, so that there is a problem that the processing efficiency is poor.

An object of the present invention is to make it possible to recover from a failure in a short time.

[0012]

SUMMARY OF THE INVENTION When switching between a working system and a standby system in a duplexed communication system, a system switching control method according to the present invention performs processing related to system switching control according to the priority of the processing. Into multiple processing groups,
The startup timing is changed for each processing group, and the process of detecting a failure and switching systems when a failure occurs is executed in the shortest cycle in the processing group whose startup timing is changed.

FIG. 1 is an explanatory view of the principle of the system switching control method of the present invention, and shows the contents of the switching control processing when the processing related to the system switching is divided into a plurality of processing groups.

In FIG. 1, processing related to system switching control needs to be executed periodically with a processing group (processing group 1) requiring a short processing time. Group that does not require the processing (processing group 2), a processing group that is not as time-limited as processing groups 1 and 2, or a processing group that only needs to be executed when requested by an operator (processing group 3). Are divided into three processing groups (steps S1, S3, S5 in FIG. 1). The activation timing of each processing group is made different.

Further, the switching control apparatus of the present invention for switching between the active system and the standby system includes a plurality of processing groups obtained by dividing processing related to system switching control according to the priority of each processing, Switching control means for determining whether or not it is time to start the group. This switching control means executes the switching control processing of FIG.

[0016]

In the system switching control method according to the present invention, the processing related to system switching is divided into a plurality of processing groups according to the priority of each processing, that is, the processing time required for each processing. . For example, a processing group (S1 in FIG. 1) including a process of detecting a failure and a process of switching from the active system to the standby system when the failure is detected, is always executed in order to recover from the failure in a short time. The processing group 2 that needs to be executed periodically is activated when the processing group 2 is activated (S2, YE
S) Executed (S3), and when it is time to activate processing group 3 (S4, YES), processing of processing group 3 that may be executed at a longer time interval than processing groups 1 and 2 is executed. (S5).

Therefore, according to the system switching control method of the present invention, the failure detection and the process of switching from the active system to the standby system at the time of failure detection have the shortest cycle among a plurality of processing groups executed at different startup timings. Therefore, switching from the active system to the standby system when a failure is detected can be performed in a short time, and the reliability of the communication system can be further improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system configuration diagram of a communication system to which the system switching control method of the present invention is applied.

This communication system is a synchronous optical network. The local exchanges 11a and 11b accommodating a plurality of telephones are connected to a backbone multiplex transmission apparatus 12a, and the local exchanges 11c and 11d are connected to a backbone multiplex transmission apparatus 12b. It is connected. Backbone multiplex transmission devices 12a and 12b
The line between the active system (work line) and the protection system (protectio
n line) and the space between the two is OC-X
[SONET (synchronous optical network) is the name of the optical signal hierarchy, for example, OC-12
= 600 Mbps, OC-3 = 150 Mbps). The DX-X [S] is provided between the subscriber exchanges 11a to 11d and the backbone optical multiplex transmission apparatuses 12a and 12b.
This is the name of the optical signal hierarchy in ONET.
For example, signal transmission is performed at DS-3 = 45 Mbps, DS-1 = 1.5 Mbps). The backbone multiplex transmission devices 12a and 12b
Performs system switching control.

Next, the operation of the embodiment having the above configuration will be described. FIG. 3 is a flowchart of the switching control processing of the backbone multiplex transmission device (hereinafter, referred to as a transmission device) according to the first embodiment of the present invention.

This embodiment shows a case where a timer management process and a system switching process for maintenance work are started by a timer interrupt of a CPU. A switching control process executed by the switching control unit, which is required to end the process in as short a time as possible, such as a failure detection process and a system switching process when a failure is detected, and a timer. Some tasks require processing to be executed at regular intervals, such as management, others require a relatively long processing time, such as maintenance work or other service functions, or some require maintenance or change the operating environment. The processing that needs to be performed only when the processing is performed is divided into three processing groups based on the processing time required for each processing.

In the following, each of the grouped processes will be described. First, the presence or absence of a fault in the line and circuit of the transmission device is detected (S21 in FIG. 3). Next, the priority of the switching factor is determined (S22). In this process, if a failure has occurred in the active system, it is determined whether or not the standby system is normal. If it is normal, it is determined which operation mode is set next, and the priority of switching is determined. Determine the degree. The transmission apparatus of this embodiment can set three operation modes: an automatic switching mode, a manual mode, and a force mode. In the automatic switching mode, the system is automatically switched when a failure occurs, and the manual mode is set. In this case, system switching is performed according to the operator's request, but system switching that stops the service is not accepted. On the other hand, in the force mode, a system switching request from the operator has priority.

When the priority of the switching factor is determined from the operation mode, the system is switched according to the determination result (S23). Thereafter, it is determined whether or not an internal interrupt has occurred every 10 ms (S24). If no internal interrupt has been detected every 10ms, the process returns to step S21 to repeat the fault detection process. In the present embodiment, the switching control process is divided into three groups, and a process requiring a short period of time, such as a fault detection and system switching process, is 10 ms.
It is always executed unless a timer interrupt occurs every 500 ms or every 500 ms. Processing with lower priority such as timer management is executed when a timer interrupt occurs every 10 ms, and switching of the system by maintenance work or the like is performed. As described above, the processing lower in priority than the timer processing is executed when a timer interrupt occurs every 500 ms.

In other words, until the internal interrupt occurs every 10 ms, only the processing in the cycle A including the fault detection processing and the system switching processing is executed. Detection and recovery can be performed in a short time.

When an internal interrupt every 10 ms is detected in the determination in step S24 (S24, YES),
The timer is counted up or down based on the interrupt signal for each ms (S25). Further, a maintenance management function such as notifying an operator which system is currently used is controlled (S26).

The above-described steps S21 to S2
The processing up to 6 is the processing of cycle B, and the processing in step S2
The timer management of No. 5 and the control of the maintenance management function of Step S26 are executed in a cycle of 10 ms.

When the control of the maintenance management function in step S26 is completed, it is determined whether or not an internal interrupt (a timer interrupt of the CPU) occurs every 500 ms (S27).
If an internal interrupt has not occurred every 500 ms in this determination, the process returns to step S21 to execute a failure detection process.

On the other hand, if an internal interrupt occurs every 500 ms in the determination in step S27, the process proceeds to step S28.
Then, setting information and control information of the operating environment are acquired. Next, an operation signal of the operator due to the maintenance work is captured (S29). Then, the number of system switching, maintenance information, line quality information, and the like are collected (S30). Thereafter, notification information editing processing for notifying the monitoring device of the collected information is performed (S31).

The processing of steps S21 to S31 described above is the processing of cycle C. In the processing of cycle C, the processing from the acquisition of the setting / control information of S28 to step S3 is performed.
Processing up to notification information editing processing for one monitoring device is 500
Executed in ms cycle.

In the first embodiment, a system switching control process requires processing in a short time, such as a failure detection and system switching process, and a system switching control process at fixed time intervals, such as timer management. There is a request that needs to be executed at a time interval that is not as short as the detection), a request that does not require processing in a relatively short time such as a switching process for maintenance work, or a request from the operator. Those that need to be executed only when necessary are divided into three processing groups according to the required processing time. Processing groups that need to be performed in a short time, such as failure detection and system switching processing, are executed in a short cycle A, and processing groups such as timer management are executed in a cycle B longer than the cycle A. Is executed in the cycle C longer than the cycle B.

Therefore, even if a failure occurs in the active system of the transmission device, it is possible to switch to the standby system in a short time,
The reliability of the transmission device can be improved. Next, a second embodiment of the present invention will be described with reference to the flowchart of FIG. 4 in which the activation timing of the grouped timer management processing groups and the activation timing of the switching processing group for maintenance work are set when an external interrupt occurs. .

First, the presence or absence of a fault in the line and circuit of the transmission device is detected (S41 in FIG. 4). Next, the priority of the switching factor is determined (S42). In determining the priority, if a failure has occurred in the active system, it is determined whether or not the standby system is normal. If it is normal, the next operation mode, that is, the automatic switching mode, the manual mode,
It is determined which of the force modes is set and the switching priority is determined. When the priority of the switching factor is determined, the system is switched according to the determination result (S43). Thereafter, it is determined whether or not an external interrupt has occurred every 10 ms (S44). If no external interrupt has occurred, the process returns to step S41 to repeat the fault detection processing.

In other words, until the external interrupt occurs every 10 ms, only the processing of the cycle A including the failure detection processing and the system switching processing is executed. Since the processing time of the cycle A is shorter than the processing times of the later-described cycles B and C, the failure can be detected and recovered in a short time.

When an external interrupt every 10 ms is detected in the determination in step S44 (S44, YES), a timer management process is executed, and the timer is counted up or down based on a signal every 10 ms (S4).
5). Further, control of a maintenance management function such as notifying an operator which system is currently used (S4).
6).

That is, when an external interrupt occurs every 10 ms, the above-described steps S41 to S41 are executed.
The processing of cycle B up to 46 is executed. Step S
When the control of the maintenance management function of 46 is completed, the next 500
It is determined whether an external interrupt for each ms has occurred (S4).
7). If no external interrupt is detected every 500 ms in this determination, the process returns to step S41 to execute a failure detection process.

On the other hand, if an internal interrupt occurs every 500 ms in the determination in step S47, the next step S4
In step 8, setting information and control information of the operating environment are acquired. Next, an operation signal of the operator due to the maintenance work is captured (S49). Then, the number of system switching, maintenance information, line quality information, and the like are collected (S50). Thereafter, a notification information editing process for notifying the monitoring device of the collected information is performed (S51).

That is, when an external interrupt occurs every 500 ms, the processing of the cycle C from step S41 to step S51 described above is executed. This second
In the embodiment, normally, a failure detection process in cycle A and a system switching process are executed, and when an external interrupt occurs every 10 ms, a timer management process for updating a timer is executed, and an external interrupt occurs every 500 ms. At this time, system switching processing for maintenance work is performed, so that failure detection and recovery can be performed in a short time.

Next, a third embodiment of the present invention in which the start timing of the timer management processing group and the start timing of the switching processing group due to maintenance work are performed when an internal interrupt occurs and when an external interrupt occurs will be described with reference to the flowchart of FIG. This will be described with reference to FIG.

In the third embodiment as well, the processing related to system switching is grouped according to the processing time required for each processing.
, The timer management processing group is executed in the cycle of cycle B, and the switching processing group for maintenance work is executed in cycle C.

The difference between the flowchart of the third embodiment and the flowchart of the first embodiment is that the determination as to whether or not it is the start timing of the switching process group by the maintenance work in step S67 of FIG. 5 is made every 500 ms. This is done by an external interrupt.

The third embodiment is also similar to the first and second embodiments described above.
As in the embodiment, processing related to system switching is grouped, and failure detection and system switching when a failure is detected are completed in a shorter cycle than before, so that failure of the transmission device can be shortened in a short time. Can be restored.

In the above-described embodiment, the case where the system switching control processing is divided into three processing groups based on the processing time required for each processing has been described. However, the number of groups to be divided is reduced to three. The present invention is not limited to this, and may be two or may be divided into four or more groups.

[0043]

According to the present invention, the processing related to system switching is divided into a plurality of processing groups according to the priority of each processing, and the activation timing of each processing group is changed, so that, for example, a failure Processing time related to detection and recovery from a failure can be shortened, and the failure can be recovered in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a switching control method according to the present invention.

FIG. 2 is a system configuration diagram of a communication system according to an embodiment.

FIG. 3 is a flowchart of a switching control process according to the first embodiment.

FIG. 4 is a flowchart of a switching control process according to a second embodiment.

FIG. 5 is a flowchart of a switching control process according to a third embodiment.

FIG. 6 is a flowchart of a conventional switching control process.

[Explanation of symbols]

 S1 processing group 1 S2 processing group 2 S3 processing group 3

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 29/14 G06F 11/20 310 H04L 1/22

Claims (6)

(57) [Claims] 1. A switching control method for switching between a working system and a standby system of a duplexed communication system, wherein processing related to system switching control is divided into a plurality of processing groups according to processing priorities. The startup timing is changed every time, and the failure detection and the system switching process when the failure occurs are executed in the shortest cycle in the processing group in which the startup timing is changed. Switching control method for a communication system. 2. The method according to claim 1, wherein a timer interrupt is used as the activation timing for each processing group.
A method for controlling switching of the described system. 3. A switching control device for switching between an active system and a standby system, wherein a plurality of processing groups obtained by dividing processing related to system switching control according to the priority of each processing, and activation of each processing group. A switching control device comprising: switching control means for determining whether or not it is a timing. 4. The plurality of processing groups include a first processing group for detecting a failure and switching a system when a failure occurs, a second processing group for updating a timer, and a system for maintenance. A third processing group for performing switching, wherein the determination processing includes, after execution of the first processing group, a first determination processing of determining whether or not it is a start timing of the second processing group; 4. The switching control device according to claim 3, further comprising a second determination process for determining whether or not it is the activation timing of the third processing group in a cycle longer than a determination cycle of the first determination process. 5. The switching control device according to claim 3, wherein the determination process determines whether a timer interrupt has occurred. 6. The switching control device according to claim 3, wherein the determination process determines whether an external interrupt has occurred.