JPH11266275A - Redundancy system of communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a system that is inexpensive and redundant by controlling the switching of two adjoining node devices that bidirectionally connect plural node devices in a loop shape, based on a result of mutually supervision of an operation state and functioning it as the current system or a spare system to one communication terminal. SOLUTION: Two ATM exchange devices 0 if a node B can notify a mutual state via an Ethernet (R) interface 9 and are connected to a common terminal device 11 via a switching device 10. The device 11 is capable of communicating with both of two current and spare system ATM exchange device 0 by switching the device 10. The current and spare system ATM exchange devices 0 are communicable and incommunicable with the device 11, because an ATM switch 12 is connected to or disconnected from a terminal interface 7. Thus, it is possible to obtain a system that is inexpensive and redundant without the use of an additional device, such as opticals coupler and light switches.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a redundant system for a communication system using an optical interface / optical cable, and more particularly, to a redundant system without using an additional device such as an optical coupler or an optical switch. The present invention relates to a redundancy system for a communication system that can be constructed.

[0002]

2. Description of the Related Art For example, in a communication system using an optical interface / optical cable, an asynchronous transfer mode (ATM: Asynchronous Transfer Mode) is used as a node device constituting the system.
Some use an ATM switching device having a switching function of a synchronous transfer mode.

FIGS. 7 and 8 show an example of a conventional system redundancy method using an ATM switching device. FIG. 7 shows a flow of communication data (normal communication state) when communication is performed using the active ATM switching device 13, and FIG. 8 shows that a failure of the active device 13 shown in FIG. 7 is detected. In this case, the flow of communication data when communication is performed using the standby system device 13 is shown.

Here, the optical coupler 17 is a device for branching a one-port optical input into multiple ports and outputting the light, and an optical switch 16 selects one port from the multi-port optical input and performs optical output. It is a device to do. The ATM switching device 13
Has port switching means for the optical coupler 17 and the optical switch 16.

The active and standby ATM switching devices 13 are
Connect with the other cable (two ATM exchanges 13
Are regarded as one node), and these two ATM switching devices 13 notify each other of the status (normal / failure) via an Ether cable.

[0006] In addition, 2 connected by an Ether cable
The ATM switching devices 13 are connected to a common terminal device 11 via the switching device 10.

[0007] The terminal device 11 can communicate with either one of the two ATM switching devices 13 by switching the switching device 10. But at the same time
It cannot communicate with one ATM switching device 13.
The ATM switching device 13 has means for switching the switching device 10.

As described above, in the conventional ATM switching system redundancy system, a standby ATM switching device 13 having the same function as the working ATM switching device 13 is prepared, and the working ATM switching device 13 is provided. When a failure occurs, switching between the optical coupler 17 and the optical switch 16 is performed to perform communication using the standby ATM switching device 13 and continue the operation of the system, thereby achieving system redundancy. .

[0009]

As described above, in the conventional redundant system of the ATM switching system, one node in the system is connected to an active ATM switching device and a standby ATM switching device. When forming a redundant configuration using
For one node, one optical coupler and one optical switch are required, and switching means for switching between the optical coupler and the optical switch must be prepared.

However, devices for handling light, such as the optical coupler and the optical switch, are expensive because the optical device is expensive.
The device itself is also expensive.

For this reason, it is impossible to construct an inexpensive redundant system by a conventional method in which an expensive device must be installed for each redundant node.

Therefore, the present invention solves the above problem,
An object of the present invention is to provide a redundancy system for a communication system that can construct a redundant system without using an additional device such as an optical coupler and an optical switch.

[0013]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of node devices are connected in a loop by two-way transmission lines having different transmission directions, and a plurality of node devices are connected on the loop. Communication means for connecting two adjacent node devices; monitoring means for monitoring the operation state of each of the node devices via the communication means; and selective communication between one of the two node devices and a communication terminal. Switching means for switching connection; and switching control means for controlling switching of the switching means based on a monitoring result of the monitoring means. Alternatively, it is characterized by functioning as a standby system.

According to a second aspect of the present invention, in the first aspect of the present invention, a failure occurs in a terminal interface of the active node device during communication with the communication terminal connected to the active node device. In this case, the communication terminal is switched and connected to a standby node device.

According to a third aspect of the present invention, in the first aspect of the present invention, if a failure occurs in the active node device during communication with the communication terminal connected to the active node device, The transmission path is looped back by a node device adjacent to the active node device on the loop, and the communication terminal is switched to a standby node device for connection.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the node device includes an asynchronous transfer mode (AT
M) is an ATM switching device having a switching function of M).

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an overall outline of the present invention will be described.

According to the present invention, an inexpensive redundant system can be provided by constructing a redundant system without using an additional device such as an optical coupler or an optical switch, as in the related art. The present invention relates to a communication system having a redundant system.

Hereinafter, an embodiment of a redundancy system for a communication system according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration and a normal communication state of an ATM switching system to which a redundancy system of a communication system according to the present invention is applied.
The redundancy is achieved by making two adjacent node devices on the loop function as an active system or a standby system for one communication terminal.

In FIG. 1, ATMs constituting the system
The switching device 0 includes a cell light input / output interface port (1) 3 (cell light input interface port (1) 1 and cell light output interface port (1) 2), a cell light input / output interface port (2) 6 (cell light Input interface port (2) 4 and cell light output interface port (2) 5), terminal interface 7 for accommodating terminal device 11, switching device switching means 8, Ethe
It has an r interface 9 and has an ATM switch 12 built therein. The ATM switch 12 has a cell input / output interface port (1) 3,
(2) It performs a switching operation of cells input from 6 and terminal interface 7 and outputs cells to cell input / output interface ports (1) 3, (2) 6 and terminal interface 7.

The ATM switching apparatus 0 has a cell input / output interface port # (1) 3 or (2)
6} and a cell input from the terminal interface 7 are output to the same cell input / output interface port {(1) 3 or (2) 6} or the terminal interface 7 as the cell was input. Is provided. The loopback operation will be described later in detail.

The two ATM switching devices 0 are connected to the Eth
The status (normal / failure) of each other can be notified via the er cable.

Two A's connected by an Ether cable
The TM switching device 0 is connected to a common terminal device 11 via a switching device 10.

The terminal device 11 can communicate with either of the two ATM switching devices 0 by switching the switching device 10. However, it is not possible to communicate with the two ATM switching devices 0 at the same time.

In this embodiment, the ATM switching device 0 in communication with the terminal device 11 is referred to as the active device according to the setting state of the switching device 10 and the ATM switching device in a state separated from the terminal device 11. 0 is called a standby system device. In the example shown in FIG. 1, of the two ATM switching devices 0 of the node B, the one shown above is the active system,
Shown below is the state of the standby system.

In the active system, the ATM switch 1
2 and the terminal interface 7 are in a connected state, the terminal device 11 and the ATM switching device 0 can communicate with each other, and in the standby device, the ATM switch 12 and the terminal interface 7 are in a disconnected state. The device 11 and the ATM switching device 0 cannot communicate with each other.

As described above, according to the above configuration, a redundant system can be constructed without using an additional (expensive) device such as an optical coupler or an optical switch as in the related art. An inexpensive redundant system can be provided.

Next, a description will be given of a redundancy system when the terminal interface 7 of the active ATM switching apparatus 0 shown in FIG. 1 has failed.

FIG. 2 is a diagram showing a communication state when the terminal interface 7 of the active ATM switching apparatus 0 shown in FIG. 1 has failed.

In the communication state shown in FIG.
When a failure occurs in the terminal interface 7 of the TM exchange 0, first, the switching device 10 is switched to the terminal device 1
0 is disconnected from the active system and connected to the standby system device.

Then, the terminal interface 7 is separated from the ATM switch 12 in the active system device, and the ATM switch 12 and the terminal interface 7 are separated in the standby system device.
Connect.

As described above, by performing the above operations, the terminal interface 7 of the active ATM switching apparatus 0 is
2 is in a communication state as shown in FIG. 2, and the standby apparatus can be operated to continue the operation of the system.

Next, a description will be given of a redundant system in the case where the ATM switch 12 or the cell input / output interface ports (1) 3, (2) 6 of the active ATM switching apparatus 0 shown in FIG.

FIG. 3 is a diagram showing a communication state when the ATM switch 12 or the cell optical input / output interface ports (1) 3, (2) 6 of the active ATM switching apparatus 0 shown in FIG. 1 has failed. .

In the communication state shown in FIG.
When a failure occurs in the ATM switch 12 or the cell optical input / output interface ports (1) 3 and (2) 6 of the TM switching apparatus 0, first, the same processing as that performed when the terminal interface 7 described in FIG. Perform the operation. That is, the switching device 10 is switched, and the terminal device 11 is disconnected from the active system and connected to the standby system device. Then, in the active system, the ATM switch 12 sends the terminal interface 7
And the ATM switch 12 and the terminal interface 7 are connected in the standby system.

Then, the active system device that has failed further is disconnected from the system. Specifically, the cell optical input / output interface port (1) is connected to two ATM switching devices 0 (one of the two is the standby device) adjacent to the failed active device on the loop. ) 3 or (2) 6
By using the loopback function of outputting the cell input from the same port as the cell input port, looping back all the cells to be output to the failed active device, the active device is output from the system. Disconnect.

As described above, by performing the above operations, the ATM switch 12 or the cell optical input / output interface port (1) 3, of the active ATM switching apparatus 0,
(2) Even when the device 6 fails, the communication device shown in FIG. 3 is established by disconnecting the failed active device from the system, and the standby device can be operated to continue the operation of the system.

FIG. 4 is a diagram showing a schematic configuration of the ATM switching apparatus 0 shown in FIG. 1 and an example of a normal switching state. In this case, the ATM switch 12 is connected to the cell optical input / output interface port (1). 3) The cell input operation from the cell optical input interface port (1) 1 and the terminal interface 7 is switched, and the cell input from the cell optical input interface port (1) 1 is exchanged with the terminal interface 7 side. Output interface port (2) 6-cell light output interface port (2)
4 shows a state where a cell input from the terminal interface 7 is output to the cell output interface port (2) 4 of the cell input / output interface port (2) 6 side.

FIG. 5 is a diagram showing a schematic configuration of the ATM switching apparatus 0 shown in FIG. 1 and an example of a switching state when loopback is performed in the ATM switch 12. In this case, the ATM switch 12 The cell input / output interface port (1) of the cell optical input / output interface port (1) 3 and the cell input from the terminal interface 7 are exchanged, and the cell input from the cell optical input / output interface port (1) 1 is changed. Loopback is performed in the terminal interface 7 and the ATM switch 12 to output to the cell light output interface port (1) 2 on the cell light input / output interface port (1) 3 side and to input the cell input from the terminal interface 7 A
This figure shows a state in which loopback is performed in the TM switch 12 and output to the cell light output interface port (1) 2 on the cell light input / output interface port (1) 3 side.

FIG. 6 is a diagram showing a schematic configuration of the ATM switching apparatus 0 shown in FIG. 1 and an example of a switching state when loopback is performed in the cell optical input / output interface port (2) 6. In the case, the ATM switch 12 is connected to the cell optical input / output interface port (1).
The cell exchange operation of the cell input from the cell optical input interface port (1) 1 and the terminal interface 7 is performed, and the cell input from the cell optical input interface port (1) 1 is exchanged with the terminal interface 7 side. In the output interface port (2) 6, loopback is performed to output the cell light output interface port (1) 2 on the side of the cell light input / output interface port (1) 3 and to convert the cell input from the terminal interface 7 into a cell. This figure shows a state in which loopback is performed in the optical input / output interface port (2) 6 and output to the cell optical output interface port (1) 2 on the side of the cell optical input / output interface port (1) 3.

The loopback operation described above may be performed at the point in FIG. 5 or at the point in FIG.

[0043]

As described above, according to the present invention,
A plurality of node devices are connected in a loop by two-way transmission paths having different transmission directions, and communication means for connecting two adjacent node devices on the loop is provided. Monitoring means for monitoring an operation state; switching means for selectively switching and connecting one of the two node devices to the communication terminal; and switching for controlling switching of the switching means based on a monitoring result of the monitoring means. Control means, so that two adjacent node devices on the loop function as an active system or a standby system for one communication terminal.
As in the related art, for each node forming a redundant configuration, for example, a redundant system can be constructed without using an additional device such as an optical coupler or an optical switch,
Thereby, an inexpensive redundant system can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration and a normal communication state of an ATM switching system to which a redundancy system of a communication system according to the present invention is applied.

FIG. 2 is a diagram showing a communication state when a terminal interface of the active ATM switching device shown in FIG. 1 has failed.

FIG. 3 shows a communication state when an ATM switch or a cell optical input / output interface port of the active ATM switching apparatus shown in FIG. 1 fails.

FIG. 4 is a diagram showing an example of a schematic configuration of the ATM switching apparatus shown in FIG. 1 and an example of a normal switching state;

FIG. 5 is a schematic configuration of an ATM switching device shown in FIG.
FIG. 4 is a diagram illustrating an example of a switching state when loopback is performed in a TM switch.

FIG. FIG. 2 is a diagram illustrating an example of a schematic configuration of the ATM switching apparatus illustrated in FIG. 1 and a switching state when loopback is performed at a cell optical input / output interface port.

FIG. 7 is a diagram showing an example of a redundant system for an ATM switching system using a conventional ATM switching device.

FIG. 8 is a diagram showing an example of a redundancy system of an ATM switching system using a conventional ATM switching device.

[Explanation of symbols]

 0 ATM switching device 1 Cell light input interface port (1) 2 Cell light output interface port (1) 3 Cell light input / output interface port (1) 4 Cell light input interface port (2) 5 Cell light output interface port (2) Reference Signs List 6 Cell light input / output interface port (2) 7 Terminal interface 8 Switching device switching means 9 Ether interface 10 Switching device 11 Terminal device 12 ATM switch

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takeshi Kanzaki 3-1-1 Asahigaoka, Hino-shi, Tokyo Inside Toshiba Communication Technology Corporation

Claims (4)

[Claims] 1. A communication unit for connecting a plurality of node devices in a loop by two-way transmission paths having different transmission directions, connecting two adjacent node devices on the loop, and via the communication unit. Monitoring means for monitoring the operation state of each of the node devices; switching means for selectively switching and connecting one of the two node devices to the communication terminal; and switching means based on a monitoring result of the monitoring means. Switching control means for controlling switching, wherein two adjacent node devices on the loop are caused to function as an active system or a standby system for one communication terminal. method. 2. During communication in a state in which the communication terminal is connected to an active node device, if a failure occurs in a terminal interface of the active node device, the communication terminal is switched to a standby node device. The redundancy system for a communication system according to claim 1, wherein the connection is established. 3. A node adjacent to the active node device on the loop when a failure occurs in the active node device during communication with the communication terminal connected to the active node device. 2. A redundancy system for a communication system according to claim 1, wherein the transmission line is looped back by a device, and the communication terminal is switched and connected to a standby node device. 4. The system according to claim 1, wherein said node device is an ATM switching device having an asynchronous transfer mode (ATM) switching function.