JPH09135244A - System changeover method for cell switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system changeover method for a cell switch capable of simplifying a system control function and easily dealing with the trouble during system changeover operation. SOLUTION: This method is provided with cell switches 2A and 2S switching and storing an inputted cell by the output destination, line interfaces 11..., 31... which temporarily hold the received input cell to output to a cell switch (2A) specified by group information, stop the output of cell to the cell switches 2A and 2S during the reception of an output stop signal and output the storing cell of the cell switch (2A), and a system controller 40 which outputs the active/ standby groups of the cell switches 2A and 2S by system information, outputs an output stop signal by the generation of a system switching request, helds the signal, checks the residence of the cell stored in the cell switches 2A and 2S by buffer storing information and outputs system information of system switching to stop the output of the output stop signal when the residence of the cell exists no longer.

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 of a cell switch that is duplicated by an active system and a standby system, and particularly, a system control function can be simplified and a problem during system switching operation can be easily dealt with. The present invention relates to a cell switch system switching method.

In recent years, ATM has been used in the communication of digital information.
(Asynchronous Transfer Mode) is frequently used, and an ATM cell switch usually employs a duplex system of an active (Active) system and a standby (Stanby) system.

[0003]

2. Description of the Related Art Conventionally, in this type of cell switch system switching system, as shown in FIG.
TM cell switches 9A and 9S buffers 9A2 and 9S2
Is monitored and controlled to ensure cell continuity. FIG.
It is a connection state diagram in the middle of system switching.

A technique for guaranteeing the continuity is described in, for example, Japanese Patent Application Laid-Open No. 5-7213. In this description, the active system path in operation outputs the input to the switch 9A1 of the active ATM cell switch 9A by the input side system switching device 91, as indicated by the broken line of the input side system switching device 91 in FIG. Further, the switch 9A1 is connected to the output side system switching device 94 via the buffer 9A2. Active ATM connected to the system switching devices 91 and 94
The system switching signal instructing the cell switch 9A is output from the external control device 95 to each of the input side and the output side.

In this system, the ATM is switched from the active system to the standby system.
When switching the cell switch, first, the external control device 95
Sends an input side system switching signal to the input side system switching device 91, switches the input cell from the switch 9A1 of the active ATM cell switch 9A to the switch 9S1 of the standby ATM cell switch 9S, and at the same time outputs the standby ATM cell. Output a cell control signal to the buffer 9S2 of the switch 9S,
The cell output from the buffer 9S2 to the output side system switching device 94 is suppressed.

Next, the external control unit 95 determines the active AT.
The cell storage status of the buffer 9A2 of the M cell switch 9A is monitored by an empty monitoring signal, and when all the cells are output from the buffer 9A2 and become empty, an output side system switching signal is output to the output side system switching device 94. Therefore, the system switching device 94 determines that the cell take-out destination is the active ATM cell switch 9
It switches from A to the standby ATM cell switch 9S, takes out from the buffer 9S2, and outputs it.

[0007]

According to the conventional cell switch system switching method described above, when switching the ATM cell switch from the active system to the standby system, first, the active system ATM cell switch is switched to standby by the system switching device on the input side. At the same time as switching to the system ATM cell switch, the output of cells from the standby system ATM cell switch to the system switching device on the output side is suppressed.
When the cell storage status of the buffer of the active ATM cell switch is monitored and becomes empty, the system switching device on the output side switches the active ATM cell switch to the standby ATM cell switch.

With this configuration, the active system changes from the active system to the standby system.
When switching the TM cell switch, the input side and the output side are switched at different timings, and since both the active system and the standby system ATM cell switches are operating at the same time, the system control becomes complicated and the system switching operation is in progress. There is a problem that the problem of is likely to spread to all lines.

An object of the present invention is to provide a system switching system of a cell switch which can simplify a system control function and can easily deal with a defect during system switching operation.

Since the cells are normally handled in the "ATM" mode, the description of "ATM" will be omitted.

[0011]

The cell switch system switching system according to the present invention stops the cell output at the input side line interface of the cell switch when the system switching request is generated due to a predetermined condition, and is in use. System switching is suspended while the cells output from the active cell switch remain in the active cell switch, and then when the active cell switch has no cells remaining, the active system becomes the standby system and the standby system. Means for canceling the output stop of the cell after switching the system to the active system.

[0012] Further, one embodied configuration is to switch the input cell by output destination and store the duplicated two cell switches, and to temporarily hold the cell input received from the incoming line. While outputting the cell to the active cell switch designated based on the system information received separately,
While receiving the output stop signal, stop outputting the cell to the cell switch, while taking out the cell stored in the active cell switch and outputting it to the output line, and the two cells The active or standby system of the switch is notified to the line interface by system information, and when a system switching request is generated under a predetermined condition, an output stop signal is sent to the line interface and the active cell switch is sent to the active cell switch. Check the stored cell retention with the buffer storage information, and when the cell retention is exhausted, output the system information that switched the active system to the standby system and the standby system to the active system to the line interface, and then output it. And a system control function for stopping the sending of the stop signal.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the present invention. In the system switching system of the cell switch shown in FIG. 1, N line interfaces 11 to 1 are provided on the input side.
Each of the active cell switch 2A and the standby cell switch 2S connecting N connects the line interfaces 31 to 3N corresponding to the N input sides to the output side, and switches between the active and standby systems. It is assumed that the control function 40 is controlling.

Each of the line interfaces 11 to 1N includes an input line buffer 111 to 11N and an output control function 121.
To 12N, and the line interfaces 31 to 3N have switch selection functions 311 to 31N, respectively. The active cell switch 2A and the standby cell switch 2S have switches 21A and 21S and buffers 22A and 22S, respectively. The system control function 40 also has a system switching hold function 41.

FIG. 1 is different from the conventional one in that the incoming line buffers 111 to 11N are installed and the system information and output stop signal is sent by the system switching hold function 41.

Next, each functional block will be described.
First, each of the N input line buffers 111 to 11N receives cells from the input side line and temporarily stores them. The output control functions 121 to 12N are connected to the active and standby switches 21A and 21S, respectively, and the cells in the respective incoming line buffers 111 to 11N are designated by the system information received from the system control function 40. It is output to either the active system switch 21A or the standby system switch 21S, but the output of the cell is stopped while the output stop signal is received from the system control function 40.

Each of the switches 21A and 21S receives cells from the N output control functions 121 to 12N, separates them for each output destination, and sends them to the corresponding destinations of "1 to N" in the buffers 22A and 22S. The buffers 22A and 22S have buffers 1 to N corresponding to the output destination line interfaces 31 to 3N, respectively, and store the received cells in one of the buffers 1 to N, and store the staying information output means (not shown). ) Sends buffer storage information indicating the storage state of cells (for example, presence / absence of accumulated cells) to the system switching hold function 41 of the system control function 40.

The switch selection functions 311 to 31N are connected to the buffers 22A and 22S, and the system control function 40
Buffers 22A, 22 based on the designation of system information received from
One of S is selected, the stored cell is taken out from the corresponding buffer among the buffers 1 to N, and is output to the output side line. In addition, the system switching hold function 41, when switching the system information, until the output 22 of the input side is controlled until it is confirmed by the buffer storage information that the cells are not accumulated in the buffer 22A of the active cell switch 2A. The output stop signal is sent to 12N and the sending of the system information for switching the system from the system information sending means (not shown) is suspended.

Next, referring to FIG. 1, the cell input to the line interface 11 from the input side is the line interface 3
The operation from N to output to the output side will be described.
The system switching hold function 41 of the system control function 40 uses the system information to
It is assumed that the operating side is the active cell switch 2A and the standby side is the standby cell switch 2S.

First, the cell input to the line interface 11 is temporarily stored in the input line buffer 111. When the cell is stored in the incoming line buffer 111, the output control function 121 is notified of the operation of the active cell switch 2A by the system information. Therefore, the output control function 121 takes out the cell stored in the incoming line buffer 111 and outputs "A". It outputs to the switch 21A on the side. In the active cell switch 2A, the switch 21A
Outputs the received cell to the buffer 22A-N corresponding to the output line interface 3N. In the line interface 3N, since the switch selection function 31N has been notified of the operation of the active cell switch 2A by the system information from the system switching hold function 41, the buffer 22A on the "A" side
-The stored cell is fetched from N and output to the output side line.

Next, with reference to FIG. 1 and FIG. 2 together, a procedure for switching between the active system and the standby system will be described.

First, as described above, it is assumed that the active cell switch 2A is operating (procedure S1) according to the system information sent by the system switching suspension function 41 of the system control function 40.

Now, when a system switching request is generated (step S2), the system control function 40 sends an output stop signal to the input side line interfaces 11 to 1N, so that the line interface 11 to 1N output control function 121. ~ 12N stop the output of the cell upon receiving this output stop signal (procedure S
3) On the other hand, the system control function 40 checks the cells currently staying in the active cell switch 2A in operation by the buffer storage information notified from the buffer 22A (step S4).

"No cell retention" (YES in step S5)
In this case, the system control function 40 receives the system information from the system information sending means by receiving it according to the buffer storage information and switching the operating side to the standby system, and each of the line interfaces 11 to 1N, 31 to 3N receiving this system information. Processes the standby cell switch 2S up to now as the operating side (step S6). As a result, each of the line interfaces 31 to 3N performs an operation of taking out the cells stored in the corresponding buffers 22S-1 to 22S on the "S" side.

Next to the switching operation in step S6 by sending the system information, the system control function 40 stops sending the output stop signal to the line interfaces 11 to 1N on the input side. Line buffer 1
The output stop of the cells stored in 11 to 11N is released (step S7). As a result, a cell is output to the switch 21S of the standby cell switch 2S, the standby system becomes the operating side, and the operation as the active system (step S8) is started.

[0027]

As described above, according to the present invention, when a system switching request is generated under a predetermined condition, cell output is stopped at the input side line interface of the cell switch and output from the active cell switch. While the cells to be stored stay in the active cell switch, switching of the system is suspended, and then when the active cell switch stops storing cells, the active system becomes the standby system and the standby system becomes the active system. After the system is switched, a system switching system of the cell switch that releases the cell output stop is obtained. With this configuration, in the system switching system of the cell switch according to the present invention, only the active system operates and the standby system waits for the operation until the switching is completed and the standby system starts operating after the system switching request is generated. Therefore, the system control function can be simplified, and it is easy to deal with problems during system switching operation.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing one form of a system switching procedure in FIG.

FIG. 3 is a functional block diagram showing an example of the related art.

[Explanation of symbols]

 11-1N (input side) line interface 111-11N (input line) buffer 121-12N output control function 2A active cell switch 2S standby cell switch 21A, 21S switch 22A, 22S buffer 31-3N (output side) line interface 311 to 31N Switch selection function 40 system control function 41 system switching hold function

Claims (5)

[Claims] 1. In a system switching system of a cell switch duplicated by an active system and a standby system, when a system switching request is generated under a predetermined condition, cell output is stopped at an input side line interface of the cell switch. Along with the cells output from the active cell switch staying in the active cell switch, switching of the system is suspended, and then when the active cell switch has no cells remaining, the active system becomes the standby system. A system switching system for a cell switch, comprising means for canceling the output stop of the cell after switching the standby system to the active system and switching the system. 2. In a system switching system of a cell switch that is duplicated by an active system and a standby system, two duplicated cell switches that store an input cell by switching each destination and store the cell from an incoming line. It receives an input and temporarily holds it, and outputs the held cell separately to the active cell switch specified based on the system information received, while outputting the cell to the cell switch while receiving the output stop signal. On the other hand, the line interface for taking out the cell stored in the active cell switch and outputting it to the outgoing line, and for notifying the active or standby system of the two cell switches to the line interface by system information When a system switching request is generated under a predetermined condition, an output stop signal is sent to the line interface and the active cell switch Check the buffer storage information for the stagnation of the cells stored in the switch, and when the stagnation of the cells is exhausted, after sending the system information to the line interface, the system in which the active system is switched to the standby system and the standby system is switched to the active system. And a system control function for stopping the output of the output stop signal and canceling the cell output. 3. The cell switch according to claim 2, wherein the cell switch switches an input cell for each output destination and outputs the cell, a buffer for storing the cell output from the switch, and a buffer for each output destination. And a staying information output means for outputting the staying status of stored cells as the buffer storage information. 4. The line interface according to claim 2, wherein on the input side, an incoming line buffer for temporarily holding a cell input from an incoming line, and an active system based on the system information based on the cell held in the incoming line buffer While being output to the cell switch, while having an output control function of stopping the output of the cell to the cell switch while receiving the output stop signal, on the output side, it is stored from the active cell switch based on the system information. A system switching system for cell switches, which is equipped with a switch selection function that takes out the selected cells and outputs them to the outgoing line. 5. The system control function according to claim 2, wherein the system information sending means sends, to the line interface, system information in which the two cell switches are designated as one of an active system and a standby system, and a predetermined condition. When a system switching request is generated by the system, the output stop signal is sent to the line interface, and the buffer storage information sent from the active cell switch is checked. After the system information for switching the active system to the standby system and the standby system to the active system is transmitted to the information transmitting means, a system switching hold function for canceling the output stop signal and canceling the cell output stop is provided. Characteristic cell switch system switching method.