JPH09312614A - Optical interface automatic changeover system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical interface automatic changeover system switching automatically an active system transmission line or a standby system transmission line connecting to an optical interface without terminating a main signal and without the need for installation of an excess optical fiber transmission line. SOLUTION: When a transmission line selection judging section 6a detects a fault in a transmission line 3d, an optical switch 2a is switched to select a standby system transmission line 4 from an active system transmission line 3. Then a transmission line information transmission section 5a sends prescribed transmission line selection information, which is synthesized with a main signal by a wavelength division multiplex(WDM) coupler 9a and the resulting signal is fed to a WDM coupler 10b. The WDM coupler 10b distributes the received transmission line selection information to a transmission line selection judging section 6b. The transmission line selection discrimination section 6b switches an optical switch 2b based on the received transmission line selection information so as to select the standby system transmission line 4 from the active system transmission line 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission system in which two stations are connected by a working transmission line and a protection transmission line, and the transmission line is selected without terminating the main signal while maintaining the optical interface. The present invention relates to an optical interface automatic switching method for switching.

[0002]

2. Description of the Related Art A conventional example will be described with reference to the drawings. FIG. 2 is an explanatory diagram showing a conventional example. Conventionally, an optical transmission system has a redundant configuration including an active transmission line 3 and a standby transmission line 4 in consideration of system stability. Each of the working transmission path 3 and the protection transmission path 4 is composed of a pair of an upstream transmission path and a downstream transmission path.

In such an optical transmission system, when a failure occurs in a part of the transmission lines, from the viewpoint of maintainability and operability, not only the transmission line in which the failure has occurred is switched, but the entire system is not switched. A switching method for switching between is adopted. That is, when a failure occurs in the active transmission line 3, the entire active transmission line 3 is switched to the standby transmission line 4.

Further, the abnormality of the transmission line is constantly monitored by the network operation system 21 connected to the optical switches 2a and 2b via the line 20. The network operation system 21 is a device that immediately issues an alarm and informs the operator when an abnormality such as a signal disconnection is detected on the transmission path. That is, conventionally, an operator manually performs a transmission path switching operation based on an alarm issued by a network operation system.

[0005]

As described above, in the conventional transmission line switching method in the optical transmission system, the operator manually switches the transmission lines.
Also, in order to automate this conventional switching method,
It is very uneconomical to install a dedicated optical fiber transmission line for transmitting and receiving transmission line switching information between the optical switches. The present invention is for solving such a problem, and it is possible to automatically provide a working system transmission line and a standby system transmission line without terminating a main signal and without laying an extra optical fiber transmission line. The purpose of the present invention is to provide an optical interface automatic switching method that switches manually.

[0006]

In order to achieve such an object, an optical interface automatic switching system according to the present invention is provided with a transmission line information transmitting means for transmitting predetermined transmission line selection information provided in a first station. And a first wavelength multiplexing means provided in the first station for multiplexing the main signal and the transmission path selection information, and a signal provided in the second station and multiplexed by the first wavelength multiplexing means. Then, the second wavelength multiplexing means for demultiplexing the main signal and the transmission path selection information from this signal and the transmission path selection information demultiplexed by the second wavelength multiplexing means provided in the second station are received. , And a transmission path selection judging means for selecting a transmission path system according to the transmission path selection information. With this configuration, the present invention can multiplex the transmission path selection information and the main signal, and simultaneously transmit and receive both signals between the optical switches.

[0007]

Next, details of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, station A and station B are provided between the transmission line 1a and the transmission line 1b.
The station and the B station are connected to each other by an active transmission line 3 and a standby transmission line 4. The transmission of the main signal between the A and B stations is performed via the active transmission line 3 in the normal state. The active transmission line 3 is composed of an upstream transmission line 3u and a downstream transmission line 3d. The backup transmission line 4 is also an upstream transmission line 4u and a downstream transmission line 4
d and has the same configuration as the active transmission line 3.

The configuration of station A will be described in detail. Station A is composed of an optical switch 2a, a receiver and a transmitter. The receiving unit includes a transmission path selection determining unit 6a and an optical / electrical converting unit 8
a, 12a and WDM (Wavelength D)
ivision Multiplexing) couplers 10a and 14a. The transmission unit is connected to the transmission path information transmission unit 5a and electricity /
It is composed of optical converters 7a and 11a and WDM couplers 9a and 13a which are wavelength multiplexing means.

The optical switch 2a changes the transmission line system connected to the transmission line 1a from the active transmission line 3 to the standby transmission line 4.
Alternatively, it is a device for switching from the backup transmission line 4 to the active transmission line 3. WDM couplers 9a, 10a, 13a, 1
Reference numeral 4a is a device that demultiplexes or multiplexes the signal received through the transmission path for each wavelength. Electric / optical converters 7a and 11a
Is a device that converts an electrical signal into an optical signal, and the optical / electrical conversion units 8a and 12a are devices that convert an optical signal into an electrical signal. The transmission path selection determination unit 6a is a device that controls the switching operation of the optical switch 2a according to the signal received from the transmission path. The transmission path information sending unit 5a is a device that outputs predetermined transmission path selection information according to the output of the transmission path selection determining unit 6a, that is, according to the state of the transmission path.

This transmission path selection information can be arbitrarily set in the transmission path information sending section 5a. For example, if the transmission path selection information is configured by the failure status of the transmission path (whether there is an abnormality) and information about the system of the selected transmission path, the pattern will be (current system transmission path failure, standby system transmission path being selected). , (Abnormal transmission line error, active transmission line selected), (No abnormality on active transmission line and standby transmission line, active transmission line selected), (Errors on active transmission line and standby transmission line) It is possible to set "None", "while the backup system transmission line is being selected", etc. In addition, as is clear from FIG.
The configuration of the station is the same as the configuration of the station A, so the description thereof will be omitted.

The operation of one embodiment of the present invention having the above configuration will be described in detail. In the normal state, the main signal transmission at the stations A and B is performed by the active transmission line 3
Done through. The main signal transmitted by station B is the transmission line 3
It is supplied to the WDM coupler 10a via d and is demultiplexed into a main signal and transmission path selection information. The demultiplexed main signal is supplied to the transmission line 1a via the optical switch 2a, and the demultiplexed transmission line selection information is converted from the optical signal to the electrical signal in the optical / electrical conversion unit 8a, and then the transmission line selection judgment is made. It is supplied to the section 6a.

The transmission path selection judging unit 6a interprets the received transmission path selection information and detects whether or not the transmission path selection information is normally received. If the transmission path selection information is normally received and the pattern is (no abnormality, the active transmission path is being selected), the active transmission path 3 can be continuously used. Therefore, the transmission path selection determining unit 6a transmits a control signal to the transmission path information sending unit 5a to periodically send the transmission path selection information of the pattern (no abnormality, the active transmission path is being selected) from the transmission path information sending unit 5a. To send. This transmission line selection information is converted into an optical signal having a wavelength different from that of the main signal in the transmission line 3u in the electric / optical conversion unit 7a. Then, this optical signal is transmitted to the WDM coupler 9a.
To the B station after being multiplexed with the main signal.

The signal transmitted to the B station is transmitted through the transmission line 3u.
Is supplied to the WDM coupler 10b through the WDM coupler 10b and is demultiplexed into a main signal and transmission path selection information in the WDM coupler 10b. The demultiplexed main signal is supplied to the transmission line 1b via the optical switch 2b. The demultiplexed transmission path selection information is
The electric signal is converted by the electric conversion unit 8b and then supplied to the transmission path selection judgment unit 6b. Then, if there is no abnormality in the active transmission line 3 and the transmission line selection information can be normally received, the transmission line selection judgment unit 6b sends out the transmission line selection information as in the case of the A station, and so on. The operation of.

By the way, when an abnormality occurs in the working transmission path 3d when the main signal transmitted by the station B is received by the station A, the transmission path selection judging section 6a may normally receive the transmission path selection information. become unable. The abnormalities include signal disconnection and abnormal signal level. Therefore, when such a situation occurs, the transmission path selection judgment unit 6a controls the optical switch 2a to perform switching control from the active transmission path 3 to the standby transmission path 4. Further, the transmission path selection judging section 6a controls the transmission path information sending section 5a to transmit the transmission path selection information of the pattern (the active transmission path is abnormal, the backup transmission path is being selected).

This transmission path selection information is transmitted to the B station via the active transmission path 3u and supplied to the transmission path selection judging section 6b. The transmission path selection judgment unit 6b controls the optical switch 2b by receiving the transmission path selection information of this pattern (abnormal system transmission path abnormal, standby system transmission path is being selected), and protection from the active system transmission path 3 is performed. Switching control to the system transmission line 4 is performed.
Further, the transmission path selection determining unit 6b causes the transmission path information sending unit 5b to transmit the transmission path selection information of the pattern (the active transmission path is abnormal, the backup transmission path is being selected). The transmitted transmission path selection information is converted into an optical signal having a wavelength different from that of the main signal in the electric / optical conversion unit 11b. This optical signal is W
It is supplied to the DM coupler 13b and multiplexed with the main signal.

The signal multiplexed by the WDM coupler 13b is transmitted to the A station via the backup transmission line 4d, and WD
It is supplied to the M coupler 14a. The WDM coupler 14a demultiplexes the main signal and the transmission path selection information, and the demultiplexed main signal is supplied to the transmission path 1a via the optical switch 2a. The demultiplexed transmission path selection information is supplied to the optical / electrical conversion unit 12a and converted into an electric signal, and then supplied to the transmission path selection determination unit 6a. The subsequent operation is the same as above.

When the active system transmission line 3 is selected in the normal state, the main signal is transmitted through the active system transmission line 3 and the transmission line selection information is the active system transmission line 3 and the standby system transmission line 4. Is transmitted in both transmission lines. Further, even if an abnormality occurs in the working transmission line 3 and the system of the transmission line is switched to the protection transmission line 4, if the working transmission line 3 is repaired and becomes usable, as described above. By changing the pattern of the transmission path selection information to the standby transmission path 4 to the active transmission path 3
Can be switched to.

[0018]

As described above, according to the present invention, the first station multiplexes the predetermined transmission path selection information into the main signal by using the wavelength multiplexing means, and the second station receives the main signal. Then, the transmission path selection information is demultiplexed. for that reason,
INDUSTRIAL APPLICABILITY The present invention can monitor the state of the transmission line only by demultiplexing the transmission line selection information from the main signal, and automatically switch the transmission line system with the optical interface without terminating the main signal. You can Further, it is very economical because it is not necessary to lay an extra optical fiber transmission line.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

1a, 1b ... Transmission line, 2a, 2b ... Optical switch, 3 ... Working transmission line, 3u ... Upstream transmission line, 3d ... Downstream transmission line, 4 ... Standby transmission line, 5a, 5b ... Transmission line Information transmission section, 6a, 6b ... Transmission path selection judgment section, 7a, 7b,
11a, 11b ... Electric / optical conversion units, 8a, 8b, 12
a, 12b ... Optical / electrical converter.

Claims (2)

[Claims] 1. A working system transmission line and a protection system transmission line for connecting a first station and a second station to transmit a main signal, and a transmission line provided for the first station and the second station. In an optical interface automatic switching system including an optical switch for switching between the two, a transmission path information sending unit, which is provided in the first station and sends predetermined transmission path selection information, is provided in the first station. First wavelength multiplexing means for multiplexing a signal and transmission path selection information, and a signal provided in the second station and multiplexed by the first wavelength multiplexing means are received, and a main signal is transmitted from this signal. Second wavelength multiplexing means for demultiplexing the path selection information, and transmission path selection information provided in the second station and demultiplexed by the second wavelength multiplexing means, and received according to the transmission path selection information. And a transmission path selection determining means for selecting a transmission path system. Interface automatic switching system. 2. The optical interface automatic switching system according to claim 1, wherein the transmission path selection information is composed of information on a system to be selected and information on a failure status of the transmission path.