JP2546507B2 - Redundant line system switching method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active system (old ACT system) and a standby system (new ACT) for packetizing and communicating information.
System) and a dual line switching system.

[0002]

2. Description of the Related Art Conventionally, this kind of redundant line system switching system forcibly and instantaneously switches from the active system to the standby system, or predicts the system switching state of the line and uses a timer to switch to the next system. There are methods such as waiting for the transition to the state.

For example, in Japanese Patent Laid-Open No. 62-269537, a state monitoring function unit for monitoring the states of the central processing units of the active system and the standby system and the communication control device is provided between the active system and the standby system. When a failure is detected in the system, the failure status is notified to the active system and the operation of the active system is stopped.

After confirming this stop or due to timeout for a certain period of time, the central processing unit of the standby system is notified that an abnormality has occurred in the active system and that the standby system is to be the active system. To switch the system.

[0005]

However, in the conventional duplex line switching system, particularly the former forced forced switching system, cells are easily lost, and the latter timer is used to switch to the next system. The method of making the system wait for the transition to the state has a problem that it takes time to switch the system.

[0006]

A duplex line system switching system according to the present invention uses a system switching command in an active system transmitting means.
The first trigger cell for notifying the confirmation shown in FIG.
Stops collecting data cells when detected by
However, depending on the end of transmission of the remaining data cells,
The second trigger cell to notify the system switching timing
Transmits from the active system to the opposite node and receives the active system
The second trigger sequence from the opposite node via the active system.
Of the second trigger cell
The output of the data cell to the inside of the
At the stage, from the standby system to the opposite node in response to the system switching instruction
First trigger to notify the confirmation of system switching instruction to
Send the cell and collect the data cell using the active transmission means.
After the data is stopped, it follows the data cell from inside the local node.
The data cells to
Start the second trigger cell that notifies the switching timing
The data cells collected by
To the standby system, and the standby system receiving means switches the system.
In response to the instruction, the first node transmitted from the opposite node via the backup system
1 trigger cell is detected, and then the
Detect the second trigger cell from the
The output of data cells inside the local node is stopped by the system receiving means.
If it is stopped, it will be received after the second trigger cell.
The data cells are sequentially output to the inside of the own node . Also, a first storage means (12) for accumulating cells input via the switch receiving side driver (13) at the time of system switching, notification of transmission of the last cell of the working system and transmission of the first cell of the protection system line. A trigger cell generator (11) for generating a first trigger cell for notifying each of the above and a second trigger cell for notifying that the protection channel of the own node has received the switching instruction, the first storage means and the trigger cell generation. (10) for selecting and outputting any of the outputs of the detector, a trigger cell detector (14) for detecting the first and second trigger cells input from the line, and a system switching of the trigger cell input from the line Second storage means (15) that accumulates at times and a switch transmission side receiver (16) that transmits the output of the second storage means to the switch side
And a system switching controller (18) for controlling the first and second storage means, the selector, the switch receiving side driver and the switch transmitting side receiver according to the output of the trigger cell detector.

[0007]

According to the present invention, it is possible to switch to the standby system (new ACT system) line at high speed without data loss.

[0008]

FIG. 1 is a block diagram showing a system to which a duplex line switching system according to the present invention is applied. In the figure, 1 and 2 are nodes, these nodes 1 and 2 are devices in the system, and in particular, node 2 is provided at a remote place.

A network management system (hereinafter referred to as NMS) 3 includes nodes 1 and 2
Centrally manage. 4 is a central processing unit (hereinafter referred to as CPU)
The CPU 4 manages each device in the node 1. Reference numeral 5 is a switch group (hereinafter, referred to as SW), 6 is a gateway (hereinafter, referred to as GW), and this GW 6 performs format conversion of control channel from control information and communication channel data.

Reference numerals 7, 8 and 9 are lines, for example, line 7 is a current system (old ACT system) and line 8 is a standby system (new ACT system).
System). The node 1 is CPU4, SW5, GW
6 and lines 7, 8 and 9. The node 2 has the same configuration as the node 1, and the number of each part is A
, CPU4A, SW5A, GW6A, line 7,
8, 9 (current system (old ACT system) 7A, standby system (new ACT)
System) 8A).

The system to which the duplex line switching system is applied is centrally managed by the NMS 3.
It is composed of some devices having a line interface for packetizing information like ATM cells for communication.

FIG. 2 shows an embodiment of a duplicated line system switching system according to the present invention. In particular, FIG. 3 is a block diagram showing a system switching function unit of a line, and FIG. 3 shows a special cell for line system switching of FIG. It is a figure which shows a flow. In the figure, 10 is a selector, 11 is a trigger cell generator, and this trigger cell generator 11 has a trigger cell T119 as shown in FIG.
And a trigger cell T2 21 is generated.

Reference numeral 12 is a line transmission side FIFO that stores cells at the time of system switching, 13 is a switch reception side driver, and 14
As shown in FIG. 3, is a trigger cell detector that detects the trigger cell T1 and the trigger cell T2, 15 is a switch sending side FIFO that stores cells at the time of system switching, 16 is a switch sending side receiver, 17 is a timer, and 18 is each part It is a system switching controller that does.

The trigger cell T1 19 and the trigger cell T2 21 are special packets (ATM cells) for notifying the system switching state of the partner line interface. In particular, the trigger cell T119 notifies that the own node has received the system switching instruction. Further, the trigger cell T2 21 is for notifying the transmission of the last cell C1 20 of the working system (old ACT system) or the first cell C2 22 of the standby system (new ACT system). Also, the switch
H reception driver 13, line transmission side FIFO 12, trigger
The cell generator 11 and the selector 10 correspond to transmitting means.
Then, the trigger cell detector 14, the switch sending side FIFO1
5 and the switch sending side receiver 16 are equivalent to receiving means.
I do.

FIG. 4 is a flow chart showing a switching sequence of the opposite line transmission direction system of the working system (old ACT system) line, and FIG. 5 is a flow chart showing a opposite reception direction system switching sequence of the working system (old ACT system) line. FIG. 6 is a flowchart showing the opposite line sending direction system switching sequence of the standby system (new ACT system) line, and FIG. 7 is a flowchart showing the opposite line receiving direction system switching sequence of the standby system (new ACT system) line.

Next, the operation of the duplicated line system switching system having the above configuration will be described with reference to the flow charts of FIGS. First, from the state in which the node 1 and the node 2 are connected by the line 7 and line 7A of the active system (old ACT system), the line 8 and line 8A of the standby system (new ACT system)
When the system is switched so as to connect with each other, the NMS 3 manages the respective devices by the CPU 4 and the node 2 of the node 1.
It is necessary to instruct the CPU 4A to switch the system.

Therefore, the NMS 3 directly notifies the CPU 4 of the node 1 of the control information. Then, the control information notified to the CPU 4 is converted into a communication path data format by the GW 6, and then the line 9 and the lines 9A, S of the node 2 are transmitted.
The communication path data is again converted into the control information format by the GW 6A via the W5A and is notified to the CPU 4A.

Upon receiving the notification of the system switching instruction, the CPU 4 of the node 1 notifies the working system (old ACT system) line 7 and the standby system (new ACT system) line 8 of the control system system switching instruction. To do. Also, the CPU 4A of the node 2
Receives the notification of this system switching instruction, the active system (old A
CT system line 7A and standby system (new ACT system) line 8A
Notify the system switching instruction of the control system.

At this time, in order for the line that has received the system switching instruction from the NMS 3 to start the system switching of the telephone line, it is essential that the state of the system configuration is the same as that of the opposite line.
Therefore, when the standby system (new ACT system) circuit 8 of the node 1 and the standby system (new ACT system) line 8A of the node 2 receive the notification of the system switching instruction of the control system, the trigger generator 1
1 is operated to send the trigger cell T1 19 to the opposite line.

Then, the standby system (new ACT system) line that has received this trigger cell T1 19 is the active system (old ACT).
By notifying the (system) line of the system switching completion of the control system of the opposite node, the system configuration states of the opposite line can be recognized with a minimum delay time.

According to the above description, using the trigger cells T1 19 and T2 21 which are special cells,
By exchanging the minimum necessary information about the system switching state of the opposing line interface units in real time, the time required for system switching can be shortened.

Then, the operation of switching the communication path system in the opposite line sending direction of the working system (old ACT system) line will be described with reference to FIG. First, when the system switching instruction is received (step SA1), the timer 17 is started (step SA
2) Monitor the system switching end notification of the control system of the opposite node from the backup system (new ACT system) line (step SA
3).

Before the time is over (step SA1
0), or when the opposite node system switching completion notification is received before the self node (step SA3: Yes),
The timer 17 is stopped (step SA4), and the cell takeover from the SW is stopped as a normal system switching operation (step SA5).

Further, the timer is over (step S
A10 / Yes), the CPU is notified of the timer over (step SA11), and it is determined that the system switching sequence is abnormal, and the system is switched to the forced system switching operation (step SA1).
2). When the cell transaction from the SW is stopped (step SA5), a cell take-over start instruction is sent to the standby system (new ACT system) line (step SA6).

When cell transmission to the opposite line is completed (step SA7), the trigger cell T2 21 is transmitted subsequently to the final cell C1 20 (step SA).
8) The standby system (new ACT system) line is notified of the completion of cell transmission to the opposite line (step SA9), and the switching of the communication path system in the opposite line transmission direction is completed.

Next, the operation of switching the communication path system in the opposite line receiving direction of the working system (old ACT system) line will be described with reference to FIG. First, the system switching instruction is received (step SB1). Then, from the opposite line, the trigger cell T2
21 is received (step SB2), the trigger cell T
The last cell C1 20 received before 2 21 is sent to the SW (step SB3).

Therefore, the cell transmission to the SW is stopped (step SB4), the standby system (new ACT system) line is notified of the cell transmission start instruction to the SW (step SB5), and the communication line in the opposite line reception direction is transmitted. The system switchover can be completed.

Next, the communication path switching operation in the opposite line sending direction of the backup system (new ACT system) line will be described with reference to FIG. First, when the system switching instruction is received (step SC1), the trigger cell T1 19 is transmitted to the opposite line (step SC2). And the active system (old ACT
When the cell take-in start instruction from the (system) line is received (step SC3), the cell take-up from the SW is started (step SC4).

Before sending the first cell C2 22 received from SW to the opposite line, the trigger cell T2 21 is sent (step SC5), and the opposite line is notified of the start of cell sending (step SC6). Then, the cell transmission completion notification from the other system to the opposite line is monitored (step SC7), and when this is received (step SC7, Yes), the switching of the communication path system in the opposite line transmission direction is completed (step SC).
8).

Next, referring to FIG. 7, the operation of switching the communication path system in the opposite line receiving direction of the standby system (new ACT system) line will be described. First, when the system switching instruction is received (step SD1), the reception of the trigger cell T1 19 from the opposite line is monitored (step SD2), and this is received (step SD2, Yes), and the working system (old ACT system) line is received. Sends the opposite node system switch end notification to (step SD
3).

Then, from the opposite line, the trigger cell T2 2
When 1 is received (step SD4), first cell C2 2
2 is taken in as a cell to be sent to SW, and a cell sending instruction from the working (old ACT) line to SW is monitored (step SD5). When the cell transmission instruction to the SW is received (step SD5, Yes), the cell transmission to the SW is started (step SD6), and the switching of the communication path in the opposite line receiving direction is finished (step SD7).

Then, the standby system (new ACT system) line notifies the CPU of the completion of the system switching by the completion of the switching of the communication line system in the opposite line transmitting / receiving direction of the own line, and the CPU completes the system switching completion. You can be notified.

As described above, when the line interface unit receives a system switching instruction from the NMS 3 upon switching the redundant line, the line interface unit of the working system (old ACT system) takes over the cells from the inside of the device. Then, the line interface of the standby system (new ACT system) is allowed to take cells from the inside of the device.

Then, a sufficient buffer (line transmission side FIFO) for accumulating cells in the line interface section of the standby system (new ACT system) until the transmission of the accumulated cells of the active system (old ACT system) is completed. And switch transmission side FI
FO) is prepared.

Then, the line interface unit of the working system (old ACT system) is configured to permit the cell transmission to the inside of the apparatus, and the loss of the cell is avoided.

[0036]

As described above in detail, according to the duplex line system switching method according to the present invention, it is possible to realize high-speed line system switching without data loss. Moreover, there are effects such as improvement of communication reliability and reduction of the buffer amount required for line switching.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system to which a duplex line switching system according to the present invention is applied.

FIG. 2 is a configuration diagram showing an embodiment of a duplicated line system switching system according to the present invention.

FIG. 3 is a diagram showing a flow of a special cell for switching the line system of FIG.

FIG. 4 is a flowchart showing an opposite line transmission direction system switching sequence of a working system (old ACT system).

FIG. 5 is a flowchart showing an opposite reception direction system switching sequence of a working system (old ACT system) line.

FIG. 6 is a flowchart showing a switching sequence of the opposite line transmission direction system of the standby system (new ACT system) line.

FIG. 7 is a flowchart showing an opposite line reception direction system switching sequence of a backup system (new ACT system) line.

[Explanation of symbols]

 1 node 2 node (remote location) 3 network management system (NMS) 4,4A CPU 5,5A switch group (SW) 6,6A gateway (GW) 7,8,9 line 10 selector 11 trigger cell generator 12 line transmission side FIFO 13 Switch receiving driver 14 Trigger cell detector 15 Switch sending FIFO 16 Switch sending receiver 17 Timer 18 System switching controller

Claims (2)

(57) [Claims] With centralized control by 1. A network management system, and duplicated configuration in the active system line and protection line between nodes with line interface for performing communication by packetizing information to the data cell, the network
In response to a system switching instruction from the management system,
Switching the communication line from the active system to the standby system at each switching node
In the redundant line system switching method, each node sequentially transfers a predetermined data cell from its own node before system switching.
Next take and send from the active node to the peer node
It is transmitted from the opposite node via the active transmission means and the active system before system switching.
Active system that receives the received data cells and outputs them to its own node
Receiving means and a predetermined data cell from within the node itself after switching the system
It is assumed that the next system will take over and transmit from the standby system to the opposite node.
Data transmission from the opposite node via the equipment transmission means and the standby system after system switching.
Standby system receiving means for receiving the network
And the active system transmitting means notifies the confirmation of the system switching instruction.
When the trigger cell of 1 is detected by the standby system receiving means
To stop collecting data cells and
System switching depending on the end of transmission of the data cell
The second trigger cell to notify the
To the second node from the opposite node via the active system.
Detection of the second trigger cell and detection of this second trigger cell
The output of the data cell to the inside of the own node is stopped in accordance with the
Notify the peer node of confirmation of system switchover
1 trigger cell is transmitted, and the data transmission is performed by the active transmission means.
After the data collection is stopped, the
Data cells that follow the data cell
The second task that notifies the system switching timing
Is the data cell retrieved with the Riga cell at the top a standby system?
From the standby system to the opposite node in sequence, and the standby system receiving means passes through the standby system according to the system switching instruction.
Then detects the first trigger cell transmitted from the opposite node
Then the second bird from the opposite node via the backup system.
While detecting the gas cell, the active system reception means
If the output of data cells to the internal
Note that the data cell received after the second trigger cell is
A duplex line switching system characterized by sequentially outputting to the inside of a node . 2. A switch receiving side driver in a line switching system in which a node having a line interface for performing centralized management by a network management system and packetizing information for communication has a dual structure of a working line and a protection line. First storage means for accumulating cells input via the cell at the time of system switching, and a first trigger cell for notifying the transmission of the last cell of the working system and the transmission of the first cell of the protection system line and its own node A trigger cell generator for generating a second trigger cell notifying that the standby system line has received a switching instruction, and a selector for selecting and outputting one of the outputs of the first storage means and the trigger cell generator, A trigger cell detector for detecting the first and second trigger cells input from the line, and a trigger cell input from the line Second storage means for accumulating at the time of system switching, a switch transmission side receiver for transmitting the output of the second storage means to the switch side, first and second storage means, a selector, according to the output of the trigger cell detector, A duplex line system switching method comprising a system switching controller for controlling a switch receiving side driver and a switch transmitting side receiver.