JP2001358655A - Adm optical transmitter having trouble-avoiding function and optical network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the conventional ADM optical transmitters which have no optical switch or spare optical line where a trouble occurring in an optical transmitter disposed between terminal units brings all signals communicating trough that transmitter become communication disabled state. SOLUTION: Upon the occurrence of a trouble in an ADM optical transmitter 102 at an intermediate node, an optical input signal are made to bypass the transmitter in trouble through optical switches 121, 122, 131, 132, thus enabling communication astriding over across the failed transmitter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ADM optical transmission device,
In particular, when a failure occurs in the device, an A provided with a function of securing a transmission route by bypassing the inside of the failed device with an optical signal as it is.
The present invention relates to a DM optical transmission device and an optical network constituted by the optical transmission device.

[0002]

2. Description of the Related Art SDH (Synchronous Di)
ADM (Add Drop Multiplexin) used in a digital hierarchy network
g: Demultiplexing and insertion multiplexing) FIG. 1 shows an example of a connection configuration of a conventional ADM optical transmission device having no protection optical line or optical switch in the optical transmission device. The optical transmission devices 001 to 003
A pair of optical transmission lines 00 each comprising a bidirectional optical fiber
Optical interface units 010, 0 connected to 4,005
20, 030 and 040. The optical interface unit performs optical-to-electrical signal conversion (O / E) and electric-to-optical signal conversion (E / O), and converts the SDH frame signal converted into an electric signal into an optical signal. The frame extraction and overhead (O) are performed by the receiving signal processing unit 013, the optical receiving signal processing unit 023, the optical receiving signal processing unit 033, and the optical receiving signal processing unit 043.
H) After processing the information, the cross-connect unit 015,
Demultiplexing is performed by the cross-connect unit 025 and the cross-connect unit 045. Now, signals A and B are transmitted from optical transmission apparatus 001 to A
Assuming that the signal B is communicated with the DM optical transmission device 002 and the signal B is communicated between the optical transmission device 001 and the optical transmission device 003, the optical signal is multiplexed by the optical transmission device 001 and converted to an optical level. The signals A and B passed through the transmission line 004 pass through the optical interface unit 02 of the ADM optical transmission apparatus 002.
After being converted to an electric signal at 0 and terminating OH, etc.,
The signal A is transmitted from the cross-connect unit 025 to a downstream device of the ADM optical transmission device 002. The signal B is sent from the cross connect unit 025 to the optical interface unit 030,
After being converted into an optical signal again, it is transmitted to the optical transmission device 003 through the optical transmission path 005. In the optical transmission device 003, after the signals are converted by the optical interface unit 040 and the cross-connect unit 045, the signal B is transmitted to the downstream device.

[0003]

The ADM optical transmission device 00
2. If a device failure such as input power loss occurs,
Both signals A and B are in a communication disabled state until the failure of the ADM optical transmission device 002 is restored. Here, in the conventional ADM optical transmission device without an optical switch and a protection system optical line, a signal transmitted via the failure generating device due to a device failure of the optical transmission device disposed between the terminating devices. There is a problem that all communication is disabled. An object of the present invention is to provide an optical signal in a faulty device for a signal terminated in a device other than the device in which the device fault occurs even if a device fault occurs in a device arranged between devices performing communication. It is an object of the present invention to provide an optical optical transmission device and an optical network that can communicate by securing a transmission route by bypassing.

[0004]

According to the first aspect of the present invention, there is provided an ADM optical transmission apparatus having a failure avoidance function, comprising: a first optical transmission line for transmitting an optical signal in both directions of upstream and downstream; An optical transmission device (ADM optical transmission device) that is connected between transmission lines and multiplexes and demultiplexes a signal bidirectionally for each time slot on the optical transmission line, wherein a failure has occurred in the ADM optical transmission device. At this time, the A
A means for directly transmitting an optical signal input to the DM optical transmission device to the second optical transmission line and an optical signal input to the ADM optical transmission device from the second optical transmission line as the first signal;
Means for transmitting to an optical transmission line.
AD with fault avoidance function according to claim 2 of the present invention
2. The M optical transmission device according to claim 1, wherein the failure occurring in the ADM optical transmission device causes the ADM optical transmission device to transmit an optical signal input from the first optical transmission line to the ADM optical transmission device. A failure that makes it impossible for the device to send the signal to the second optical transmission line after the demultiplexing process, or an optical signal input from the second optical transmission line to the ADM optical transmission device is transmitted to the ADM optical transmission device. In the above, when one of two failures, one of which is impossible to be transmitted to the first optical transmission line after the demultiplexing processing, is one of the two optical signals which suffers from the failure is directly opposed. It is characterized by having means for transmitting to an optical transmission line. The ADM optical transmission device with a failure avoidance function according to the third aspect of the present invention is the ADM optical transmission device according to the first aspect, wherein the failure that occurs in the ADM optical transmission device according to the first aspect of the present invention is performed from the first optical transmission path. A failure in which an optical signal input to the ADM optical transmission device cannot be transmitted to the second optical transmission line after the demultiplexing process in the ADM optical transmission device, or Either one of the two failures, a failure in which the optical signal input to the optical transmission device cannot be transmitted to the first optical transmission line after the demultiplexing process in the ADM optical transmission device. Means for transmitting the two optical signals as they are to the opposing optical transmission lines. An ADM optical transmission apparatus with a failure avoidance function according to claim 4 of the present invention is the ADM optical transmission apparatus according to claims 1 to 3.
In the ADM optical transmission device with a failure avoidance function according to the invention according to the invention, means for converting an optical signal input from the first optical transmission line into an electric signal, means for performing a demultiplexing process on the converted electric signal, Means for converting the processed electrical signal back to an optical signal, means for bypassing the optical signal, and means disposed between the first optical transmission line and the means for converting the optical signal to an electrical signal; A first optical switching unit that switches the optical signal to a unit that converts the optical signal into an electric signal and a unit that bypasses the optical signal; a unit that converts the processed electric signal into an optical signal again; The optical signal from the bypass unit and the optical signal from the unit for converting the electric signal into an optical signal again, the optical signal being provided between the first optical transmission line and a second optical transmission line different from the first optical transmission line. Switch to the second optical transmission path and send Characterized in that it comprises a second optical switching means. An ADM optical transmission apparatus with a failure avoidance function according to the fifth aspect of the present invention is the ADM optical transmission apparatus with a failure avoidance function according to the fourth aspect of the present invention,
Further, the ADM optical transmission device with the failure avoidance function is provided with means for monitoring a failure that occurs in the ADM optical transmission device and controlling a switching operation of the optical switching means when a failure occurs. According to a sixth aspect of the present invention, there is provided an optical network in which the ADM optical transmission device with a failure avoidance function according to the first to fifth aspects is connected in cascade via an optical transmission line to form a ladder type. It is characterized by. An optical network according to a seventh aspect of the present invention is configured such that the ADM optical transmission device with a failure avoidance function according to the first to fifth aspects of the present invention is connected in a ring form via an optical transmission line. It is characterized by.

[0005]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a connection configuration of the first embodiment of the ADM optical transmission device having a failure avoidance function according to the present invention. In FIG. 2, an ADM having an optical switch
When a device failure occurs in which the line of the optical transmission line is completely disconnected in the optical transmission device 102, the optical switches 121, 122, 13
1 and 132 can be switched to the optical bypass lines 151 and 152 so that signals that are communicating between the optical transmission devices 101 and 103 can be made communicable. In FIG. 2, it is assumed that the optical transmission apparatuses 101 and 103 are terminating apparatuses, and a single-stage ADM optical transmission apparatus 102 is inserted between the terminating apparatuses, and a failure occurs in the ADM optical transmission apparatus 102. are doing. 2, the ADM optical transmission apparatus 102 includes an optical interface unit 120 on the left side (referred to as the east side), an optical interface unit 130 on the right side (referred to as the west side), an optical bypass line 151 and an optical bypass line 152, Cross connect part 153
And a device failure monitoring control unit 150. The optical transmission apparatuses 101, 102, and 103 are connected by an EAST-side optical transmission path 104 and a WEST-side optical transmission path 105, which are bidirectional optical transmission paths.

[0006] The optical interface section 120 has a receiving side for receiving an optical signal from the EAST side transmission line 104 as a receiving side.
The O / E conversion unit 123 converts the electric signal into a frame synchronization signal and an overhead (O / E).
H) The receiving side signal processing unit 125 that extracts and processes information is provided. The transmitting side of the optical transmission line includes a transmitting side signal processing unit 126 for inserting OH information and an E / O converting unit 124 for converting a multiplexed electric signal into an optical signal. Also,
The optical signal input from the EAST-side optical transmission line 104 is converted by the optical switch A121 into an O / E converter 123 or an optical bypass line connected to the optical switch B132, which converts the optical signal into an electric signal for signal processing in its own device. Fifteen
1 to any one of the following. In the optical switch B122, an E / E that converts an electric signal processed in the device into an optical signal is used.
One of the optical signal from the O conversion unit 124 and the optical signal bypassed from the optical switch A131 through the optical bypass line 152 is selected, and the optical signal is transmitted to the opposing device via the EAST-side optical transmission line 104. These optical switches A,
As B, a waveguide type optical switch utilizing an electro-optical effect represented by a directional coupler type optical switch, a mechanical optical switch having an electromagnetic driving mechanism, or the like can be used.
The control of the optical switch is performed by turning on / off the voltage applied to the optical switch according to the output signal from the device failure monitoring control unit. The device failure monitoring and control unit 150 sets the optical switches A and B to the ON state during normal operation, and sends a control signal for connecting the optical transmission line to the O / E converter or the E / O converter to the optical switches A and B. To send to. Then, when a device failure occurs such that the transmission optical signal of the optical transmission line 104 and the optical transmission line 105 connected to the ADM optical transmission device 102 including the power input abnormality and the internal device timing control unit abnormality is completely interrupted. Controls the optical switches A and B so that the control signal output to be sent to the optical switches A and B is turned off to select the optical bypass line side. Cross connect part 153
Separates the multiplexed signal received from the optical interface unit, and separates (DRO)
P) The signal to be output is output from the ADM optical transmission device 102 to the downstream device, and a signal obtained by multiplexing the signal input from the downstream device and the signal to be transmitted to another optical transmission device again is output to the optical interface units 120 and 130. It has the function of sending to The other functional blocks required for the operation of the apparatus and not described are not shown because they are not directly related to the present invention.

Next, the detailed operation of the configuration diagram of FIG.
The flow will be described as an example. In FIG. 2, a signal A is a signal communicated between the optical transmission device 101 and the ADM optical transmission device 102, and a signal B is a signal communicated between the optical transmission devices 101 and 103. Also, functional blocks having the same name in each device perform exactly the same processing. Signal A, B
After being multiplexed with other signals in the cross-connect unit 117 of the optical transmission apparatus 101, the optical transmission-side signal processing unit 116 inserts an OH and sends it to the E / O conversion unit 114. E
The signal converted into the optical signal by the / O converter 114 is sent to the EAST-side optical transmission line 104. In the ADM optical transmission device 102, the signals A and B are input to the optical switch A121 through the EAST-side optical transmission line 104. During normal operation of the ADM optical transmission device 102, the device failure control monitoring unit 150 sends a high level switching signal 154 to the optical switch A121, and the optical signal in which the signals A and B are multiplexed is sent to the O / E conversion unit 123. Sent out. Then, after being converted into an electric signal by the O / E conversion unit 123, the OH information is terminated by the optical reception-side signal processing unit 125, only the signal A is separated and dropped by the cross-connect unit 153, and the downstream device is transmitted. Output. The signal B is multiplexed with another signal and then transmitted from the cross-connect unit 153 to the optical transmission side signal processing unit 136. The signal B is converted to an optical level by the E / O conversion unit 134, and then the optical switch B132
Is input to In the optical switch B132, the optical switch 12
Since the high-level switching signal is received from the device failure control monitoring unit 150 as in the case of 1, the optical signal from the E / O conversion unit 134 is output to the WEST side optical transmission line 105. WE
The signal received by the optical transmission device 103 through the ST-side optical transmission line 105 passes through the O / E conversion unit 143 and the optical reception-side signal processing unit 145, and the signal B is separated and dropped by the cross-connect unit 147. Output to the downstream device.
In this way, signals A and B can be communicated between the optical transmission devices.

An ADM optical transmission device 10 which is a feature of the present invention
In the case where a device failure in which the line of the optical transmission line is completely disconnected occurs in the second example, this is referred to as a first example of the first embodiment. The fault monitoring unit 150 sends the low-level switching signal to the optical switch A12.
1, by sending out to the optical switch B122, the optical switch A131, and the optical switch B132, the optical switch A121,
131 outputs a signal to the optical bypass lines 151 and 152, and the optical switches B 122 and 132 perform an operation of selecting a signal from the optical bypass lines 151 and 152 and outputting the signal to the transmission line. Thereby, the EAST side optical transmission line 1
The optical signal inputted from the WEST side optical transmission line 105 is sent to the WEST side optical transmission line 105 as it is.
The signal input from the EAST side optical transmission line 10
4, the signal B communicated between the optical transmission apparatuses 101 and 103 becomes communicable even when a failure occurs in the ADM optical transmission apparatus 102.

In the first embodiment, a device failure that occurs in the ADM optical transmission device 102 causes a malfunction in the operation of the entire device, such as a power input abnormality or a clock abnormality in the ADM optical transmission device. Optical transmission lines 104 and 10
5 has been described in the case of a device failure in which the line transmitting 5 is completely disconnected. A failure of the cross-connect unit 153 having a function of multiplexing and demultiplexing signals at an electric level is similar to this. However, depending on the location of the failure, only one of the two-way transmission paths passes through the ADM optical transmission device as light via the optical bypass line, and the other
It is also conceivable to utilize the ADM function of the DM optical transmission device. The operation in this case is referred to as a second example of the first embodiment. For example, when a failure occurs in at least one of the O / E converter 123, the optical receiver signal processor 125, the optical transmitter signal processor 136, and the E / O converter 134, the EAST optical transmission path 104 The optical signal from the optical switch A121 and the optical switch 132 are switched to the optical bypass 151 side, and the optical signal from the optical transmission apparatus 101 is converted to the ADM.
WEST side optical transmission line 1
05 from the optical transmission apparatus 101 to the optical transmission apparatus 103
Communication to is ensured. Then, the optical switch B 122 and the optical switch A 131 receive the high-level control signal 154 of the device failure monitoring and control unit 150, communicate from the optical transmission device 103 to the ADM optical transmission device 102 and the optical transmission device 101, and transmit the ADM optical signal. From the transmission device 102 to the optical transmission device 10
Although communication to 3 is impossible, communication to only 101 can be ensured. For this purpose, the device fault monitoring and control device 150 needs to have a function of identifying or diagnosing the type of fault that has occurred in the ADM optical transmission device and transmitting different control signals 154 to the four optical switches. .

As a second embodiment of the present invention, the basic configuration is as shown in FIG. 1, but as shown in FIG. 2, an ADM optical transmission device is provided between the terminal optical transmission device 201 and the optical transmission device 20M. The case where a plurality of ADM optical transmission devices 20M-1 are connected in a ladder form is shown. Even in this case, AD
When a device failure occurs in the M optical transmission device 20N, the device 20
By transmitting a signal using an optical bypass line in the optical switch in N, the same effect that enables communication of signals C and D can be obtained. Further, as described in the second example of the first embodiment, depending on the type of a fault that occurs, one of the two-way transmission paths bypasses the failed ADM optical transmission device. In this embodiment, it is possible to secure the ADM function for the path in the other direction.

In a third embodiment of the present invention, all of the plurality of ADM optical transmission devices 301 to 303 with the failure avoidance function of the present invention are used.
FIG. 3 shows an example of a network in which these are formed in a ring shape. In this embodiment as well, the first embodiment in which the failed ADM optical transmission device is bypassed in both directions and the second embodiment in which the ADM function is secured in the other direction by bypassing only one direction are possible. It is.

[0012]

As described above, in the ADM optical transmission apparatus with a failure avoiding function according to the present invention, when a failure occurs in the ADM optical transmission apparatus of an intermediate node that relays a signal, the optical signal of the failed ADM optical transmission apparatus. By bypassing the signal inside the device by an optical switch, there is an effect of enabling communication between devices across the failure generating device. In particular, since the optical signal is bypassed as it is without depending on the synchronous multiplexing processing at the electric signal level, the reliability of the network is further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an ADM optical transmission device with a failure avoidance function according to the present invention.

FIG. 2 is a diagram illustrating a ladder-type optical network including an ADM optical transmission device with a failure avoidance function according to the present invention.

FIG. 3 is a diagram showing a ring type optical network constituted by an ADM optical transmission device with a failure avoidance function according to the present invention.

FIG. 4 is a diagram showing a configuration of a conventional ADM optical transmission device.

[Explanation of symbols]

 001 Optical transmission device 002 ADM optical transmission device 003 Optical transmission device 004 Optical transmission line 005 Optical transmission line 010 Optical interface unit 013 Optical receiving side signal processing unit 015 Cross connect unit 020 Optical interface unit 023 Optical receiving side signal processing unit 025 Cross connect Unit 030 Optical interface unit 033 Optical receiving side signal processing unit 040 Optical interface unit 043 Optical receiving side signal processing unit 045 Cross-connect unit 101 Optical transmission device 102 ADM optical transmission device 103 Optical transmission device 104 EAST-side optical transmission line 105 West-side light Transmission path 114 E / O conversion unit 116 Optical transmission side signal processing unit 117 Cross connect unit 121 Optical switch A 122 Optical switch B 123 O / E conversion unit 124 E / O conversion unit 125 Optical reception side signal processing unit 126 Transmission side signal Processing unit 1 0 Optical interface unit 131 Optical switch A 132 Optical switch B 134 E / O conversion unit 136 Optical transmission side signal processing unit 143 O / E conversion unit 145 Optical reception side signal processing unit 147 Cross connect unit 150 Device failure monitoring control unit 151 Light Bypass line 152 optical bypass line 153 cross-connect section 154 switching signal 201 optical transmission device 20M optical transmission device 202 ADM optical transmission device 20M-1 ADM optical transmission device 20N ADM optical transmission device 301 ADM optical transmission device

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) H04Q 11/04 LF term (reference) 5K002 AA05 DA04 DA11 EA05 EA31 EA33 FA01 5K019 AA08 AB07 BA57 EA28 5K028 AA14 BB08 CC02 DD05 DD06 KK03 MM14 PP02 QQ00 5K069 AA10 CA06 CB04 DB31 EA19 EA22 HA08

Claims (7)

[Claims] 1. A first method for transmitting an optical signal in both directions, up and down.
An optical transmission device (ADM optical transmission device) connected between the optical transmission line and the second optical transmission line for multiplexing and demultiplexing signals bidirectionally for each time slot on the optical transmission line, Means for transmitting an optical signal input from the first optical transmission line to the ADM optical transmission device as it is to the second optical transmission line when a failure occurs in the ADM optical transmission device, and the second optical transmission line An ADM optical transmission device with a failure avoidance function, comprising: means for directly transmitting an optical signal input from the ADM to the ADM optical transmission device to the first optical transmission line. 2. The method according to claim 1, wherein the failure occurring in the ADM optical transmission device causes an optical signal input from the first optical transmission line to the ADM optical transmission device to be transmitted to the ADM optical transmission device after the demultiplexing process. The optical signal input from the second optical transmission line to the ADM optical transmission device after the demultiplexing process in the ADM optical transmission device. Means for transmitting only one of the optical signals subjected to the failure to the opposing optical transmission line as it is when the failure is one of the two failures that cannot be transmitted to the optical transmission line. 2. The ADM optical transmission device with a failure avoidance function according to claim 1, wherein: 3. The ADM optical transmission device according to claim 1, wherein the failure occurs when the optical signal input from the first optical transmission line to the ADM optical transmission device is demultiplexed by the ADM optical transmission device after the demultiplexing process. The optical signal input from the second optical transmission line to the ADM optical transmission device after the demultiplexing process in the ADM optical transmission device. Means for sending both of the optical signals to the opposing optical transmission lines as they are, regardless of which of the two failures cannot be transmitted to the optical transmission line. 2. The ADM optical transmission device with a failure avoidance function according to claim 1, wherein: Means for converting an optical signal input from the first optical transmission line into an electric signal, means for performing demultiplexing processing on the converted electric signal, and converting the processed electric signal into an optical signal again. , A means for bypassing an optical signal, and means for converting the optical signal into an electrical signal, the optical signal being provided between the first optical transmission line and the means for converting the optical signal into an electrical signal. A first optical switching unit that switches between a unit that converts the optical signal and a unit that bypasses the optical signal, a unit that converts the processed electrical signal into an optical signal again, and a second optical switching device that is different from the first optical transmission line. And an optical signal from the means for bypassing and an optical signal from means for converting the electric signal into an optical signal again are transmitted to the second optical transmission line. Before providing a second light switching means The ADM optical transmission device with a failure avoidance function according to claim 1. 5. The ADM optical transmission device with a failure avoidance function further monitors a failure occurring in the ADM optical transmission device with a failure avoidance function, and controls a switching operation of the optical switching unit when a failure occurs. 5. The ADM optical transmission device with a failure avoidance function according to claim 4, further comprising means. 6. An optical network, wherein the ADM optical transmission device with a failure avoidance function according to claim 1 is connected in cascade via an optical transmission line to form a ladder type. 7. An optical network comprising the ADM optical transmission apparatus with a failure avoidance function according to claim 1 connected in a ring shape via an optical transmission line.