JP2003158527A - Communication network and communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost network and a node apparatus that requires only a short time from the occurrence of the failure to restoration of communications. SOLUTION: When a demultiplexer section 10a of a node 110-1 detects a failure in a receiver side active transmission line 204a, a switch section 120-1 captures a signal addressed to itself from a receiver side standby transmission line 201b to stop transmission of the signal to a transmitter side active transmission line 201a. When a demultiplexer section 10c of a node 110-2 detects the stop of the signal received from the receiver side active transmission line 201a, a switch section 120-2 captures the signal addressed to itself from a receiver side standby transmission line 202b to stop the transmission of the signal to a transmitter side active transmission line 202a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed and large-capacity optical network and a node device constituting the optical network,
In particular, the present invention relates to a network having a redundant function on a transmission line and a node device for separating a signal from the transmission line and inserting a signal into the transmission line.

[0002]

2. Description of the Related Art With the spread of the Internet, it is desired to efficiently accommodate packet data, not voice data, realize an optical network with high transmission speed, large transmission capacity, and high reliability at low cost. It is rare.

An optical ring network is known as a highly reliable high-speed large-capacity network. The optical ring network is a ring-shaped network in which a plurality of node devices are connected by optical fibers. A node device that constitutes an optical ring network is an Add / Drop multiplexer (hereinafter referred to as an ADM device) that has a function of inserting a signal such as packet data into a transmission line and separating the signal from the transmission line. .

In order to secure reliability against failures, the optical ring network has an optical fiber disconnection, an optical transmitter failure,
When various failures such as an optical receiver failure occur, it has a function (hereinafter, referred to as a protection function) of disconnecting a failure point by a loopback or switching of a transmission path to restore communication.

An example of a physical layer of an optical ring network is one using SONET / SDH frames. In SONET / SDH, since a protection function against a transmission line failure is specified, when the transmission line failure occurs, the communication can be restored by the function.

[0006] Specifically, from the ADM device on the transmission side, S
Information for network management (information such as transmission path failure and quality, automatic switching control (APS)) is added to a specific field of the overhead of the ONET / SDH frame and transmitted, and the SONET / SDH termination of the receiving ADM device is performed. The circuit analyzes the overhead to detect the failure and quality deterioration of the transmission line, and automatically switches the route.

Most SONET / SDH ADM devices perform switching in the electric signal portion after converting an optical signal into an electric signal. However, there is also an ADM device that uses an optical switch to switch the path in the optical signal portion.

As another example of the physical layer of the optical ring network, IEEE (The Institute a) is used.
nd Electronics Engineers)
10 Gbps, which is being standardized with 802.3ae
There is Ethernet WAN-PHY. this is,
It is intended to realize a low-cost network by using a SONET / SDH frame as a base and using only the minimum function of the overhead. Therefore, 10 Gbps Ethernet WAN PH
Y does not include the path switching function defined as SONET / SDH, and depends on the function of the upper layer for the path switching with respect to the failure of the transmission path.

[0009]

In the SONET / SDH network, since the automatic switching control is performed between the ADM devices by using the overhead of the SONET / SDH frame, the communication is performed by switching the route in a short time after the occurrence of the transmission line failure. Can be restored.

However, the SONET / SDH having a function of adding information for network management to the overhead and transmitting the information, analyzing the overhead to detect a failure or quality deterioration of the transmission path, and automatically switching the path. ADM
The device is expensive to implement these functions.

Further, when an optical switch is used for path switching, the optical signal is looped back, so that the distance over which the optical signal is transmitted becomes longer than in normal operation. If the transmission distance becomes long, S due to dispersion and loss in the optical fiber
The deterioration of the / N ratio becomes large. Therefore, the electro-optical converter (hereinafter referred to as E / O) is required to have high output and high dispersion resistance, and the opto-electric converter (hereinafter referred to as O / E) is required to have high reception sensitivity. , The cost of the ADM device is even higher.

On the other hand, 10 Gbps Ethernet
A device with a reduced overhead processing function, such as an ADM device using WAN-PHY, is a SONET / SDH A
The cost is lower than that of the DM device. Such a device
The route switching for the failure of the transmission line depends on the function of the upper layer. For example, a LAN located in the upper layer
As a result, the faulty route is not used due to the route selection function of the interconnection device.

However, since the route selection function by the function of the upper layer does not directly detect the fault of the transmission line to switch the route, it takes time until the route is not used after the fault occurs. , It takes longer for normal communication.

An object of the present invention is to provide a network and a node device which are low in cost and take a short time from the occurrence of a failure to the restoration of communication.

[0015]

In order to achieve the above object, the communication network of the present invention is a communication network in which three or more nodes are connected in a dual ring shape by a working transmission line and a protection transmission line. When a failure is detected in the working transmission line of the receiving side, the first node that stops the signal transmission to the working transmission line of the transmitting side by fetching the signal addressed to itself from the backup transmission line of the receiving side and the receiving side When the signal received from the working transmission line of 1 stops, the second node has a second node that takes in the signal addressed to itself from the backup transmission line of the receiving side and stops the transmission of the signal to the working transmission line of the transmitting side.

Therefore, when the first node detects a failure in the transmission line, it changes the route inside itself and stops the signal transmission to the second node to cause the second node to change the route. .

Further, when the node has the functions of the first node and the second node and a failure occurs in any of the working transmission lines, the node that detects the failure operates as the first node. However, it is preferable that all the other nodes operate as the second node so that communication between all the nodes is performed on the backup transmission path.

In another communication network of the present invention, three or more nodes are connected by a working transmission line and a protection transmission line in which respective sections between the nodes have different signal flow directions,
In a dual ring communication network, when a failure of the working transmission line of the receiving side is detected, the signal addressed to itself is taken in from the backup transmission line of the receiving side and the signal is transmitted to the backup transmission line of the transmitting side. The first node that stops the signal received from the backup transmission line of the receiving side and is not addressed to itself to the working transmission line of the transmitting side, and when the signal received from the backup transmission line of the receiving side stops, It has a second node for returning a signal received from the working transmission line and not addressed to itself to the backup transmission line on the transmitting side.

Further, when the node has the functions of the first node and the second node, and a failure occurs in any of the working transmission lines, the node that detects the failure operates as the first node. Then, the node that was transmitting the signal to the working transmission path in which the failure has occurred operates as the second node, so that communication is performed in the working transmission path and the backup transmission path other than the section in which the failure has occurred. It is preferable that

Yet another communication network of the present invention is
A communication network in which three or more nodes are connected in a dual ring shape by a working transmission line and a protection transmission line, and which transmits and receives wavelength-multiplexed signals, in which at least one wavelength of the working transmission line on the receiving side has a fault. First, the signal of the wavelength addressed to itself is fetched from the backup transmission line on the reception side, and the transmission of the signal to the wavelength to the working transmission line on the transmission side is stopped.
Node and the signal of at least one wavelength received from the working transmission line of the receiving side are stopped, the signal of the wavelength addressed to itself is taken in from the backup transmission line of the receiving side, and the signal is transmitted to the working transmission line of the transmitting side. It has a second node that stops the transmission of the wavelength signal.

Therefore, when the first node detects a failure at a specific wavelength of the transmission path, it switches its own internal path for the wavelength and stops the signal transmission to the second node to change the path. Let

Further, when the node has the functions of the first node and the second node and a fault of at least one wavelength occurs in any working transmission line, the node that has detected the fault is the first node. It is preferable that communication of the wavelength between all the nodes be performed on the backup transmission line by operating as one node and all other nodes as the second node.

Yet another communication network of the present invention is
It is a dual ring communication network in which three or more nodes are connected by working transmission lines and backup transmission lines in which the sections between the nodes are different in the signal flow direction and which transmit and receive wavelength-multiplexed signals. When detecting a failure of at least one wavelength of the working transmission line of the receiving side, the signal of the wavelength addressed to itself is taken in from the backup transmission line of the receiving side, and the transmission of the signal to the backup transmission line of the transmitting side is stopped, A first node that returns a signal of the wavelength other than its own received from the backup transmission line of the receiving side to the working transmission line of the transmitting side, and a signal of at least one wavelength received from the backup transmission line of the receiving side. When stopped, the signal of the wavelength other than that addressed to itself, which is received from the working transmission line on the receiving side, is returned to the backup transmission line on the transmitting side.
Node.

Further, when the node has both the functions of the first node and the second node and a fault of at least one wavelength occurs in any working transmission line, the node that has detected the fault is the first node. The node that was operating as the first node and was transmitting a signal to the faulty working transmission line operates as the second node, so that the working transmission line and the standby transmission line other than the faulty section It is preferable that the communication of the wavelength is performed.

The communication device of the present invention is a communication device that is connected in a dual ring shape by working and protection transmission lines to form a communication network, and a plurality of high-speed signals from the receiving side working transmission line are transmitted. When separated into low-speed signals, multiple low-speed signals are multiplexed and transmitted as high-speed signals to the working transmission line on the transmitting side, and when a failure of the working transmission line on the receiving side is detected,
And a high speed signal received from the working transmission line of the receiving side is stopped, a working demultiplexing unit that stops each low speed signal that separates the high speed signal of the working transmission line of the receiving side, and a standby transmission line of the receiving side Of the high speed signal is separated into a plurality of low speed signals, the low speed signal from the working demultiplexer is stopped when the low speed signal from the working demultiplexer is stopped, and the low speed signal from the working demultiplexer is stopped. It has a switch unit which takes in a signal addressed to itself from the low speed signals from the demultiplexing unit and stops the transmission of the low speed signal multiplexed on the transmission side working transmission line to the working demultiplexing unit.

Therefore, when a failure of the working transmission line is detected, the working demultiplexing unit which has detected the failure stops the signal transmitted on the transmission line and causes the switch unit to change the path. The switch unit stops the signal transmitted to the working transmission line, and causes another communication device to change the route.

Further, a plurality of the working demultiplexing units, the backup demultiplexing units and the switch units may be provided for each wavelength to transmit / receive wavelength-multiplexed signals.

Another communication device of the present invention is a communication device which is connected in a dual ring by working and backup transmission paths in which signals flow in different directions to form a communication network. The high-speed signal from the path is separated into a plurality of low-speed signals, multiple low-speed signals are multiplexed and transmitted as a high-speed signal to the backup transmission path on the transmitting side, and when a failure of the working transmission path on the receiving side is detected, A first demultiplexing unit that stops each low-speed signal that separates the high-speed signal of the working transmission line on the receiving side, and a high-speed signal from the backup transmission line on the receiving side is separated into a plurality of low-speed signals, Multiplexed as high-speed signals and transmitted to the working transmission line on the transmitting side, and when the high-speed signal received from the backup transmission line on the receiving side stops, each low speed that separates the high-speed signal on the backup transmission line on the receiving side Second multiplex to stop signal And parts, the low-speed signals from the first demultiplexing unit stops, stop the transmission to the first demultiplexing unit of the low-speed signals to be multiplexed to the protection transmission line of the transmission side,
From the low speed signals from the second demultiplexing unit, a signal addressed to itself is taken in, signals other than those addressed to itself are returned to the second demultiplexing unit as low speed signals, and low speed signals from the second demultiplexing unit are received. When the signal is stopped, the low-speed signal from the first demultiplexing unit has a switch unit that returns a signal other than its own signal to the first demultiplexing unit as a low-speed signal.

Therefore, when a fault in the working transmission line is detected, the working demultiplexing unit that has detected the fault stops the signal transmitted through the transmission line, and causes the switch unit to change the route. The switch unit stops the signal to be transmitted to the backup transmission line and causes another communication device to change the route.

Further, a plurality of the first demultiplexing units, the second demultiplexing units and the switch units are provided for each wavelength,
You may transmit / receive the wavelength-multiplexed signal.

Still another communication device of the present invention is a communication device which is connected in a dual ring shape by working and protection transmission lines to form a communication network and detects a failure of a working transmission line on the receiving side. , And when the signal from the working transmission line on the receiving side is stopped, the signal addressed to itself is taken in from the backup transmission line on the receiving side, and the transmission of the signal to the working transmission line on the transmitting side is stopped.

Still another communication apparatus according to the present invention is a communication apparatus which constitutes a communication network by connecting in a dual ring with working and protection transmission paths in which signals flow in different directions. When a failure is detected, the signal transmission to the backup transmission line on the transmitting side is stopped, the signal addressed to itself is taken in from the signals on the backup transmission line on the receiving side, and the signal other than its own is transmitted on the active side of the transmitting side. When the signal from the backup transmission line on the receiving side stops, the signal other than its own among the signals from the working transmission line on the receiving side is returned to the working transmission line on the transmitting side. .

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION When an add / drop multiplexer (hereinafter referred to as an ADM device) of the present invention detects a transmission line failure such as an optical signal interruption, it positively activates the link multiplexed on the transmission line. By automatically disconnecting, a path switching within itself is immediately generated, and by actively disconnecting the link of the transmission path whose path is to be switched to another, path switching within the adjacent ADM device is generated.

(First Embodiment) A first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the optical ring network of the first embodiment. Referring to FIG. 1, the optical ring network includes nodes 110-1 and 11-1.
0-2, 110-3, 110-4 and the line 201a,
201b, 202a, 202b, 203a, 203b,
It is composed of 204a and 204b.

Lines 201a, 201b, 202a, 20
Reference numerals 2b, 203a, 203b, 204a, and 204b are lines of optical fiber cables that connect nodes and transmit data.

The line 201a transmits data from the node 110-1 to the node 110-2, and the line 201b transmits data from the node 110-2 to the node 110-1. The line 202a is from the node 110-2 to the node 110.
-3 to the node 110,
-3 to node 110-2. The line 203a transmits data from the node 110-3 to the node 110-4, and the line 203b transmits data from the node 110-4 to the node 110-3. Line 204a
Transmits data from the node 110-4 to the node 110-1, and the line 204b is transmitted from the node 110-1 to the node 1
Data is transmitted to 10-4.

Lines 201a, 202a, 203a, 20
4a is a working line, and lines 201b,
202b, 203b, 204b are spare (Protect
Ion).

Nodes 110-1, 110-2, 110-
Reference numeral 3,110-4 is an ADM device for transmitting and receiving data to and from each other by inserting a signal such as packet data into an optical network and separating the signal from the optical network.
All have the same configuration.

The node 110-1 is a demultiplexer (MUX).
/ DEMUX) 10a, 10b and switch unit 120
-1.

The demultiplexers 10a and 10b perform, for example, 8: 1 demultiplexing and 1: 8 demultiplexing. Demultiplexer 1
0a separates the signal from the line 204a into eight signals and transmits them from the eight channels of the port 11a, and
Line 20 by multiplexing the signals of the eight channels of port 12a
Send to 1a. The demultiplexer 10b demultiplexes the signal from the line 201b and transmits it from the eight channels of the port 11b, and multiplexes the signals of the eight channels of the port 12b and transmits it to the line 204a.

The demultiplexing unit 10a is connected to the line 204a.
When the input disconnection of the optical signal is detected, the signal transmission to the port 11a is stopped in order to detect the link disconnection in the subsequent stage. When the demultiplexing unit 10b detects the disconnection of the optical signal of the line 201b, the demultiplexing unit 10b stops transmitting the signal to the port 11b.

The switch unit 120-1 has an Add port 22 and a Drop port 21 connected to a communication device (not shown) in the upper layer, and is connected to the demultiplexing unit 10a by the ports 11a and 12a and multiplexed. The separation unit 10b is connected to the ports 11b and 12b.

Since the switch section 120-1 is composed of 24 × 24 switches, it can output an input signal of an arbitrary channel of an arbitrary port as an output signal of an arbitrary channel of an arbitrary port. Since the working line 204a is normally active, a signal addressed to itself (that is, a signal to be passed to a higher-level communication device connected to itself) is output from the port 11a to the Drop port 21, and signals other than those addressed to itself are added. The signal from the port 22 is output to the port 12a. Further, the switch unit 120-1 outputs a signal input from the port 201b and not addressed to itself and a signal from the Add port 22 to the port 12b.

The switch section 120-1 is for the working line 20.
4a and 201a are active, and while the signal addressed to itself of port 11a is being output to Drop port 21, if input interruption of the signal of port 11a is detected, port 11b
The switch is switched so as to output the signal addressed to itself to the Drop port 21, and the output of the signal to the port 12a is stopped. The switch unit 120-1 has a port 11a.
The same switching operation is performed even when the link disconnection of the signal is detected.

If the signals of the ports 11a, 11b, 12a and 12b are optical signals, the light transmission to the port 12a may be stopped. Here, as an example, the line signal is Gbp.
In the case of sEthernet, the optical signal to the port may be stopped in order to generate Link Down. However, as long as Link Down can be generated immediately, another method may be used instead of stopping the optical signal.

Also, the ports 11a, 11b, 12a, 1
2b may be an electric signal, and in that case, transmission of a frame may be stopped so that a link disconnection can be detected at a later stage.

The node 110-2 has the same structure as the node 110-2, and has demultiplexing units 10c and 10d and a switching unit 120-2.

FIG. 2 shows the demultiplexing units 10a, 10b, 10
It is a block diagram which shows the structure of c and 10d. The demultiplexing units 10a, 10b, 10c, and 10d have the same configuration, and are shown as the demultiplexing unit 10 in FIG.

Referring to FIG. 2, the demultiplexing unit 10 has a terminating unit 13, a multiplexing unit 14, an electro-optical converting unit (EO) 15, an electro-optical converting unit (OE) 16 and a demultiplexing unit 17.

The terminating unit 13 is provided for each channel and terminates the low-speed signal of each channel in which the optical signal of the line is separated and converted into electricity, and the port 11 to the switch unit 12 are used.
Signals transmitted / received to / from an upper layer communication device (not shown) connected via 0-1 are terminated and interface conversion between these signals is performed.

When the terminal section 13 detects a link break on the line side or receives a notification of an optical signal input break from the opto-electric converter 16, the terminal section 13 stops sending the signal to the port 11 and disconnects the link. Generate.

The multiplexing section 14 multiplexes the signals from the terminal section 13 of each channel.

The electro-optical conversion unit 15 converts the signal multiplexed by the multiplexing unit 14 from electricity to light and transmits it to the line.

The opto-electric converter 16 converts an optical signal from the line into electricity. When the photoelectric conversion unit 16 detects the disconnection of the optical signal, the photoelectric conversion unit 16 notifies the termination unit 13 of the disconnection and stops the transmission of the signal to the port 11.

The separation unit 17 separates the high-speed signal converted into electricity by the photoelectric conversion unit 16 into low-speed signals for each channel.

In this example, the line is a SONET / SDH-based Gbps Ethernet frame format, and the SONET / SDH frame has a minimum of A1 and A2 bytes for synchronization, B1 and B2 bytes for error monitoring. Field is used, and the E1 byte and E2 byte of the protection function are not used.

FIG. 3 is a diagram for explaining the operation of the node of this embodiment.

As shown in FIG. 3, it is assumed that communication is interrupted due to a failure such as optical power loss in the line 204a of the optical ring network. The failure of the line 204a is caused by the demultiplexing unit 1
0a, node 110-1 stops the signal on port 11a. As a result, the link that has been using the port 11a is disconnected.

When the signal of the port 11a is stopped, the switch section 120-1 which detects it stops the signal of the port 12a. As a result, the link using the port 12a is disconnected. Then, the switch unit 120-1
The connection to the Drop port 21 is changed from the port 11a to the port 11b. By changing this port, node 1
As the recognition of 10-1, the working lines 204a, 201a
From the active state, the spare lines 204b, 201
b becomes active.

The stoppage of the signal of the port 12a is transmitted to the node 110-2 by the line 201a via the demultiplexing unit 10a.

Since the disconnection of the link is detected by the demultiplexing unit 10c, the node 110-2 stops the signal similarly to the node 110-1 and switches the switch unit 120-2. As a result, the node 110-2 recognizes that the working lines 201a and 202a are in the active state and the protection lines 201b and 202b are in the active state.

In this way, the spare lines become active one after another between the nodes, and finally all the spare lines become active and communication is restored.

Therefore, the node of the first embodiment is
When a failure in a transmission path is detected, the link transmitted on that transmission path is disconnected at the location where the failure is detected, and the switch unit changes the path. Since the node changes the route, each unit can perform a simple operation to switch the route at high speed.Therefore, it is necessary to have a complicated means for controlling the route based on the failure information collected from the entire device. No, it is low cost.

(Second Embodiment) A second embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a block diagram showing the configuration of the optical ring network of the second embodiment. Referring to FIG. 4, the optical ring network includes nodes 210-1, 21.
0-2, 210-3, 210-4 and the line 201a,
201b, 202a, 202b, 203a, 203b,
It is composed of 204a and 204b.

Lines 201a, 201b, 202a, 20
Reference numerals 2b, 203a, 203b, 204a, and 204b are lines of optical fiber cables that connect nodes and transmit data.

The line 201a transmits data from the node 210-1 to the node 210-2, and the line 201b transmits data from the node 210-2 to the node 210-1. The line 202a is connected from the node 210-2 to the node 210.
-3 to the node 210
-3 to node 210-2. The line 203a transmits data from the node 210-3 to the node 210-4, and the line 203b transmits data from the node 210-4 to the node 210-3. Line 204a
Transmits data from the node 210-4 to the node 210-1, and the line 204b is transmitted from the node 210-1 to the node 2
Data is transmitted to 10-4.

Lines 201a, 202a, 203a, 20
4a is a working line, and lines 201b,
202b, 203b, 204b are spare (Protect
Ion).

Nodes 210-1, 210-2, 210-
Reference numerals 3, 210-4 are ADM devices that insert signals such as packet data into the optical network and separate the signals from the optical network, and all have the same configuration.

The node 210-1 is a demultiplexer (MUX).
/ DEMUX) 10a, 10b and switch unit 220
-1.

The demultiplexing units 10a and 10b have the same configuration as that of the first embodiment and perform 8: 1 demultiplexing and 1: 8 demultiplexing. In the second embodiment, the demultiplexing unit 10a is
The signal from the line 204a is separated into eight signals, which are transmitted from the eight channels of the port 11a and the port 12a.
The signals of the eight channels of a are multiplexed and transmitted to the line 204b. The demultiplexing unit 10b demultiplexes the signal from the line 201b into eight signals, transmits the signals from the eight channels of the port 11b, and multiplexes the signals of the eight channels of the port 12b and transmits the signals to the line 201a.

Further, the demultiplexing unit 10a uses the line 204a.
When the input disconnection of the optical signal is detected, the signal transmission to the port 11a is stopped in order to detect the link disconnection in the subsequent stage. When the demultiplexing unit 10b detects the disconnection of the optical signal of the line 201b, the demultiplexing unit 10b stops transmitting the signal to the port 11b.

The switch unit 220-1 has an Add port 22 and a Drop port 21 connected to a communication device (not shown) in the upper layer, and is also connected to the demultiplexing unit 10a and the ports 11a and 12a for multiplexing. The separation unit 10b is connected to the ports 11b and 12b.

Since the switch section 220-1 is composed of a 24 × 24 switch, it can output an input signal of an arbitrary channel of an arbitrary port as an output signal of an arbitrary channel of an arbitrary port. Since the working lines 204a and 201a are normally active, the signal addressed to itself is separated from the port 11a and the Drop port 2
1 and outputs signals other than those addressed to itself and signals from the Add port 22 to the port 12b. Also, the switch unit 2
20-1 outputs a signal input from the port 11b to other than itself and a signal from the Add port 22 to the port 12a.

The switch section 220-1 is used for the working line 20.
4a and 201a are active and the signal of the port 11a is being output to the Drop port 21, the port 11a
When the disconnection of the signal of a is detected, the switch is switched to output the signal addressed to itself from the port 11b to the Drop port 21, the signal other than addressed to itself from the port 11b is returned to the port 12b, and the signal to the port 12a is transmitted. Stop signal output.

The switch section 220-1 performs the same switching operation even when the link break of the signal of the port 11a is detected.

Here, the signal of the line is Gbps Ether
If it is net, the optical signal to the port may be stopped to generate Link Down. However, as long as Link Down can be generated immediately, another method may be used instead of stopping the optical signal.

The node 210-2 has the same configuration as the node 210-1, and has demultiplexing units 10c and 10d and a switching unit 220-2. Node 210-4 is
Demultiplexing units 10g and 10h and switch unit 220-4
have.

FIG. 5 is a diagram for explaining the operation of the demultiplexing units facing each other in the second embodiment. The demultiplexing units 10-1 and 10-2 included in different nodes face each other. As shown in FIG.
When a failure occurs in the line from the demultiplexing unit 10-2 to the demultiplexing unit 10-1, the demultiplexing unit 10-1 detects it. When detecting the failure, the demultiplexing unit 10-1 stops the signal to the port 11-1. When the signal to the port 11-1 is stopped, the switch unit (not shown) connected thereto stops the signal to the port 12-1.

When the signal of the port 12-1 is stopped, the information is transmitted to the demultiplexing unit 10-2 of the opposite node. Then, the demultiplexing unit 10-2 that detects the disconnection of the link stops the signal of the port 11-2. When the signal of the port 11-2 is stopped, the switch unit (not shown) connected thereto stops the signal of the port 12-2.

FIG. 6 is a diagram for explaining the operation of the node of the second embodiment.

Referring to FIG. 6, it is assumed that communication is interrupted due to a failure such as optical power loss in the line 204a of the optical ring network. The failure of the line 204a is caused by the demultiplexing unit 1
0a, node 210-1 ceases to signal port 11a.

When the signal of the port 11a is stopped, the switch unit 220-1 which detects it stops the signal of the port 12a, changes the connection to the Drop port 21 from the port 11a to the port 11b, and also addresses itself. Signals other than the above are returned from the port 11b to the port 12b.

The stoppage of the signal of the port 12a is transmitted to the node 210-4 by the line 201a via the demultiplexing unit 10a. Since the link break is detected by the demultiplexing unit 10h, the node 210-4 stops the signal, and the switch unit 220-4 loops back, similarly to the node 210-1.

In this way, the faulty part is separated from the loop and a new loop is constructed, whereby communication is restored.

(Third Embodiment) A third embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a block diagram showing the configuration of the nodes that form the optical ring network of the third embodiment. In FIG. 7, only one node is shown, but the network is a ring configuration with the same nodes.

The optical network is a WDM (Wavelength Division) in which optical signals of four wavelengths are multiplexed.
It is a network of Multiplexing). The node 1000-1 is a WDM ADM device that inserts a signal such as packet data into any of the four wavelengths of the optical network and separates the signal.

The node 1000-1 includes the wavelength demultiplexing unit 41.
a, 41b, wavelength multiplexing units 42a, 42b, wavelength node 1
10-1A, 110-1B, 110-1C, 110-1
D and the wavelength node switch 130-1.

The wavelength demultiplexing units 41a and 41b demultiplex and extract four signals having different wavelengths multiplexed on the line between the nodes. The wavelength is, for example, λA = 1539.77n.
m, λB = 1546.12 nm, λC = 1552.52
nm and λD = 1558.98 nm.

The wavelength multiplexers 42a and 42b multiplex four signals having different wavelengths into one line.

Wavelength nodes 110-1A, 110-1B,
110-1C and 110-1D are the nodes 110-1 of FIG.
The configuration is the same as that of the above, and the respective signals separated by the wavelength separation units 41a and 41b are input. Wavelength node 11
0-1A, 110-1B, 110-1C, 110-1D
Separates and multiplexes signals for each wavelength. Wavelength nodes 110-1A, 110-1B, 110-1C, 1
The signals multiplexed by 10-1D are wavelength multiplexing units 42a and 42a.
The wavelength is multiplexed in b.

Wavelength nodes 110-1A, 110-1B,
110-1C and 110-1D are the nodes 110- of FIG.
Although the configuration is the same as that of No. 1, since the wavelengths of the optical signals to be handled are different, the wavelengths of the optical signals generated by the respective electro-optical conversion units are different.

The wavelength node switch 130-1 includes switch sections 120-1A, 120-1B, 120-1C and 12-1.
The Add port 132 and the Drop port 13 are connected to the Add port and the Drop port of 0-1D, and are also connected to the communication device (not shown) of the upper layer.
Have one. The wavelength node switch 130-1 can output the input of any channel of the switch units 120-1A to 120-1D to any channel.

Wavelength node switch 130-1 and switch units 120-1A, 120-1B, 120-1C and 120
With the combination of -1D, it is possible to multiplex a signal from an upper layer device into an arbitrary channel of an arbitrary wavelength, separate a signal from an arbitrary channel of an arbitrary wavelength, and transmit the separated signal to an upper layer communication device. . Also, in the same way,
It is possible to switch channels between wavelengths.

FIG. 8 is a diagram for explaining the operation of the node of the third embodiment when a failure occurs in the line between the nodes.

As shown in FIG. 8, it is assumed that the line 204a of the optical ring network suffers a failure such as optical power loss and communication of all wavelengths is interrupted. The failure of the line 204a is caused by all wavelength nodes 110-1
A, 110-1B, 110-1C, 110-1D demultiplexing unit 10a detects, and nodes 110-1A, 110
-1B, 110-1C, 110-1D stop the signal of its own port 11a.

When the signal of the port 11a is stopped, the switch unit 120-1 which detects it stops the signal of the port 12a and changes the connection to the Drop port 21 from the port 11a to the port 11b. All wavelength nodes 110-1A, 110-1B, 110-1C, 11
0-1D changes the port so that the node 100
As a recognition of 0-1, the working lines 204a and 201a are changed from the active state to the protection lines 204b and 201b.
Becomes active.

Stopping the signal of the port 12a of each wavelength node is performed by the line 201a via each demultiplexing unit 10a.
Is transmitted to each wavelength node of the adjacent node, switching occurs in all nodes in order from the adjacent node,
Eventually, all the spare lines become active and communication is restored.

FIG. 9 is a diagram for explaining the operation of the node of the third embodiment when a failure occurs in a line of one wavelength.

As shown in FIG. 9, it is assumed that a line having a wavelength λA = 1539.77 nm separated by the wavelength separation unit 41a has a failure, and communication of signals multiplexed therein is interrupted. The failure is the demultiplexing unit 10 of the wavelength node 110-1A.
a, the wavelength node 110-1A is detected as port 11a.
Stop the signal.

When the signal of the port 11a is stopped, the switch section 120-1A which detects it stops the signal of the port 12a and changes the connection to the Drop port 21 from the port 11a to the port 11b. When the wavelength node 110-1A changes the port, the wavelength λA
= 153.77 nm, the node 000-1 recognizes that the working lines 204a and 201a are in the active state and the protection lines 204b and 201a are in the active state.

The stoppage of the signal at the port 12a of the wavelength node 110-1A is stopped by the line 201 via the demultiplexer 10aA.
It is transmitted to the wavelength node of the same wavelength of the adjacent node by a, and switching occurs in all nodes in order from the adjacent node, and finally all the backup lines of that wavelength become active and communication is restored. To do. in this way,
When a failure occurs in only one wavelength, the same operation as that of the first embodiment is performed for that wavelength, and the spare line is activated for only that wavelength.

(Fourth Embodiment) A fourth embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 10 is a block diagram showing the configuration of a node which constitutes the optical ring network of the fourth embodiment. Although only one node is shown in FIG. 10,
The network is a ring structure with the same nodes.

The optical network is a WDM network in which signals of four wavelengths are multiplexed. Node 2000-
Reference numeral 1 denotes a WDM ADM device that inserts a signal such as packet data into a signal of an arbitrary wavelength among signals of four wavelengths of an optical network and separates the signal.

The node 2000-1 includes the wavelength demultiplexing unit 41.
a, 41b, wavelength multiplexing units 42a, 42b, wavelength node 2
10-1A, 210-1B, 210-1C, 210-1
D and the wavelength node switch 230-1.

The wavelength demultiplexing units 41a and 41b are the same as those in the third embodiment and demultiplex and extract the signals of four wavelengths multiplexed on the line between the nodes. The wavelengths are, for example, λA = 1539.77 nm and λB = 1546.1.
2 nm, λC = 1552.52 nm and λD = 155
It is 8.98 nm.

The wavelength multiplexers 42a and 42b are the same as those in the third embodiment and multiplex four signals having different wavelengths into one line.

Wavelength nodes 210-1A, 210-1B,
210-1C and 210-1D are the nodes 210-1 of FIG.
The configuration is the same as that of, and the signals separated by the wavelength separation units 41a and 41b are input. Wavelength node 210
-1A, 210-1B, 210-1C, 210-1D
Separates and multiplexes signals for each wavelength. Wavelength nodes 210-1A, 210-1B, 210-1C, 2
The signals multiplexed in 10-1D are wavelength multiplexing units 42a and 42a.
The wavelength is multiplexed in b.

Wavelength nodes 210-1A, 210-1B,
210-1C and 210-1D are the nodes 210- of FIG.
Although the configuration is the same as that of No. 1, since the wavelengths of the optical signals to be handled are different, the wavelengths of the optical signals generated by the respective electro-optical conversion units are different.

FIG. 11 is a diagram for explaining the operation of the node of the fourth embodiment when a failure occurs in the line between the nodes.

As shown in FIG. 11, it is assumed that the line 204a of the optical ring network suffers a failure such as optical power loss and communication of all wavelengths is interrupted. The failure of the line 204a is caused by all wavelength nodes 210-1 of the node 2000-1.
A, 210-1B, 210-1C, 210-1D demultiplexing unit 10a detects, node 210-1A, 210
-1B, 210-1C, 210-1D stop the signal of the port 11a.

When the signal of the port 11a is stopped, the switch unit 220-1 which detects it stops the signal of the port 12a, changes the connection to the Drop port 21 from the port 11a to the port 11b, and also addresses itself. Signals other than the above are returned from the port 11b to the port 12b.

Stopping the signal of the port 12a of each wavelength node is performed by the line 201a via the respective demultiplexing unit 10a.
Is transmitted to each wavelength node of the node 2000-4. The node 2000-4 stops the signal and loops back at the switch unit, similarly to the node 2000-1.

In this way, the faulty point is separated from the loop for all wavelengths and a new loop is constructed, whereby communication is restored.

FIG. 12 is a diagram for explaining the operation of the node of the fourth embodiment when a failure occurs in the line of one wavelength.

As shown in FIG. 12, the line 204a of the optical ring network is broken by the wavelength demultiplexing unit 41a and the line of wavelength λA = 1539.77 nm fails, and the communication of the signals multiplexed therein is interrupted. Suppose The failure is detected by the demultiplexing unit 10a of the wavelength node 210-1A of the node 2000-1, and the wavelength node 210-1A stops the signal of the port 11a.

When the signal of the port 11a is stopped, the switch unit 220-1A which has detected it stops the signal of the port 12a, changes the connection to the Drop port 21 from the port 11a to the port 11b, and sends it to itself. Signals other than the above are returned from the port 11b to the port 12b.

Stopping the signal of the port 12a is performed by the node 2000-through the line 201a via the demultiplexing unit 10aA.
4 wavelengths of the same wavelength are transmitted to the node 2000.
Similarly to the node 2000-1, the node -4 stops the signal and loops back at the switch unit.

As described above, when a failure occurs at only one wavelength, the same operation as that in the second embodiment is performed for that wavelength, and the failure point is separated from the loop for that wavelength to form a new loop. By doing so, communication is restored.

[0123]

According to the communication network of the present invention, a node that has detected a failure in a transmission line changes its own internal route, and at the same time, stops transmitting signals to other nodes and changes the route to other nodes. Therefore, it is not necessary to provide a complicated procedure for controlling the route between the nodes, and it is possible to realize a highly reliable communication network that can switch routes at high speed at low cost.

Further, the node that has detected the failure of the specific wavelength of the transmission path switches its own internal path for the wavelength and stops the signal transmission to other nodes to change the path. There is no need to provide a complicated procedure to control the paths of all wavelengths at low cost,
It is possible to realize a highly reliable communication network with a large transmission capacity, which enables high-speed path switching.

Further, according to the communication apparatus of the present invention, when a fault in the working transmission line is detected, the signal transmitted on the transmission line is stopped in the working demultiplexing unit which has detected the fault,
Since the switch unit changes the route, and the switch unit stops the signal to be transmitted to the working transmission line and causes another communication device to change the route, each unit performs a simple operation, so that the route can be changed at high speed. Can be switched, and there is no need to have a complicated means for controlling the route based on the failure information collected from the entire device, which is low cost.

When a fault on the working transmission line is detected,
The working demultiplexer that detected the failure stops the signal transmitted on that transmission line, causes the switch to change the route, and the switch stops the signal to be transmitted to the standby transmission line. Since the communication device changes the route, each unit can perform a simple operation to switch the route at high speed, and it is necessary to have a complicated means to control the route based on the failure information collected from the entire device. It is low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical ring network according to a first embodiment.

FIG. 2 is a block diagram showing a configuration of a demultiplexing unit.

FIG. 3 is a diagram for explaining the operation of the node according to the first embodiment.

FIG. 4 is a block diagram showing a configuration of an optical ring network according to a second embodiment.

FIG. 5 is a diagram for explaining the operation of opposing demultiplexing units in the second embodiment.

FIG. 6 is a diagram for explaining the operation of the node according to the second embodiment.

FIG. 7 is a block diagram showing a configuration of a node configuring an optical ring network according to a third embodiment.

FIG. 8 is a diagram for explaining the operation of the node of the third embodiment when a failure occurs in the line between the nodes.

FIG. 9 is a third example when a failure occurs in a line of one wavelength.
FIG. 6 is a diagram for explaining the operation of the node of the exemplary embodiment.

FIG. 10 is a block diagram showing a configuration of a node configuring an optical ring network of a fourth exemplary embodiment.

FIG. 11 is a fourth example when a failure occurs in a line between nodes.
FIG. 6 is a diagram for explaining the operation of the node of the exemplary embodiment.

FIG. 12 is a diagram for explaining the operation of the node of the fourth embodiment when a failure occurs in a line of one wavelength.

[Explanation of symbols]

10, 10-1, 10-2, 10a, 10aA, 10b
A, 10b, 10c, 10d, 10g, 10h Demultiplexing unit (MUX / DEMUX) 11, 11-1, 11-2, 11a, 11b, 12, 1.
2-1, 12-2, 12a, 12b Port 13 Termination Unit 14 Multiplexing Unit 15 Electro-Optical Conversion Unit (EO) 16 Electro-Optical Conversion Unit (OE) 17 Separation Unit 21, 131, 231 Drop Port 22, 132, 232 Add Ports 41a, 41b Wavelength demultiplexing units 42a, 42b Wavelength multiplexing units 110-1, 110-2, 110-3, 110-4, 2
10-1, 210-2, 210-3, 210-4, 10
00-1, 2000-1 to 2000-4 nodes 110-1A to 110-1D, 210-1A to 210-
1D wavelength nodes 120-1, 120-1A to 120-1D, 120-
2,220-1,220-1A to 220-1D, 220
-2, 220-3, 220-4 switch units 130-1, 230-1 wavelength node switches 201a, 201b, 202a, 202b, 203a,
203b, 204a, 204b lines

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04J 14/02

Claims (14)

[Claims] 1. A communication network in which three or more nodes are connected in a dual ring shape by a working transmission line and a protection transmission line, and when a failure of the working transmission line on the receiving side is detected, a signal addressed to itself is transmitted. Is received from the backup transmission line on the receiving side and stops transmitting signals to the working transmission line on the sending side, and when the signal received from the working transmission line on the receiving side stops, it receives the signal addressed to itself A communication network having a second node that takes in from a backup transmission line on one side and stops transmitting signals to the working transmission line on the transmitting side. 2. The node has the functions of the first node and the second node, and when a failure occurs in any of the working transmission lines, the node that detects the failure operates as the first node. The communication network according to claim 1, wherein all the other nodes operate as the second node so that communication between all the nodes is performed on the backup transmission line. 3. A dual ring communication network in which three or more nodes are connected by an active transmission line and a backup transmission line in which the sections between the nodes have different signal flow directions, When it detects a failure in the working transmission line on the receiving side, it takes in the signal addressed to itself from the backup transmission line on the receiving side, stops the signal transmission to the backup transmission line on the sending side, and receives itself from the backup transmission line on the receiving side. When the signal received from the first node that returns signals other than those addressed to the transmitting side current transmission line and the signal received from the receiving side backup transmission line stops, signals other than those addressed to itself are received from the receiving side current transmission line. A communication network having a second node that loops back to a backup transmission line on the transmitting side. 4. The node has both the functions of the first node and the second node, and when a failure occurs in any of the working transmission lines, the node that has detected the failure operates as the first node. Then, the node that was transmitting the signal to the working transmission path in which the failure has occurred operates as the second node, so that communication is performed in the working transmission path and the backup transmission path other than the section in which the failure has occurred. The communication network according to claim 3, wherein: 5. A communication network in which three or more nodes are connected in a dual ring shape by an active transmission line and a standby transmission line, and which transmits and receives wavelength-multiplexed signals, and at least the active transmission line on the receiving side. When a failure of one wavelength is detected, a signal of the wavelength addressed to itself is taken in from the backup transmission line on the reception side, and a first node that stops transmission of the signal to the wavelength to the working transmission line on the transmission side, and a reception node When the signal of at least one wavelength received from the working transmission line of the side stops, the signal of the wavelength addressed to itself is taken in from the backup transmission line of the receiving side, and the signal of the wavelength is transmitted to the working transmission line of the transmitting side. A communication network having a second node for terminating. 6. The node has both the functions of the first node and the second node, and when a fault of at least one wavelength occurs in any working transmission line, the node that has detected the fault is the first node. 6. The communication of the wavelength between all the nodes is performed on the backup transmission line by operating as one node and all other nodes as the second node. Communication network. 7. Three or more nodes are connected by an active transmission line and a backup transmission line in which respective sections between the nodes have different signal flow directions, and transmit and receive wavelength-multiplexed signals.
In a double ring communication network, when a failure of at least one wavelength of the working transmission line of the receiving side is detected, the signal of the wavelength addressed to itself is taken in from the backup transmission line of the receiving side, and the backup of the transmitting side is taken. From the first node that stops the transmission of the signal to the transmission line and returns the signal of the wavelength other than its own received from the receiving side standby transmission line to the transmitting side working transmission line, and from the receiving side standby transmission line A communication network having a second node in which, when the received signal of at least one wavelength is stopped, the signal of the wavelength other than that addressed to itself received from the working transmission line of the receiving side is returned to the backup transmission line of the transmitting side. 8. The node has the functions of the first node and the second node together, and when a fault of at least one wavelength occurs in any working transmission line, the node that has detected the fault is the first node. The node that was operating as the first node and was transmitting a signal to the faulty working transmission line operates as the second node, so that the working transmission line and the standby transmission line other than the faulty section The communication network according to claim 7, wherein communication of the wavelength is performed in the communication network. 9. A communication device, which is connected in a dual ring shape by working and protection transmission lines to form a communication network, wherein a high-speed signal from a reception-side working transmission line is separated into a plurality of low-speed signals. , A plurality of low-speed signals are multiplexed and transmitted as a high-speed signal to the working transmission line of the transmitting side, and when a failure of the working transmission line of the receiving side is detected, and when received from the working transmission line of the receiving side. When a high-speed signal is stopped, a current demultiplexing unit that stops each low-speed signal that separates the high-speed signal of the receiving-side working transmission line, and separates the high-speed signal from the receiving-side standby transmission line into a plurality of low-speed signals, A standby demultiplexer that multiplexes a plurality of low-speed signals and sends them to the backup transmission line on the transmission side, and when the low-speed signal from the working demultiplexer stops, the low-speed signals from the standby demultiplexer are addressed to themselves. The signal of A communication device having a switch unit for stopping transmission of a low-speed signal multiplexed on a working transmission line on the transmitting side to the working demultiplexing unit. 10. The communication device according to claim 9, wherein a plurality of the working demultiplexing units, the backup demultiplexing units, and the switch unit are provided for each wavelength, and wavelength-multiplexed signals are transmitted and received. 11. A communication device, comprising a plurality of high-speed signals from a receiving-side working transmission path, which is a communication device which is connected in a dual ring with working and protection transmission paths having different signal flowing directions to form a communication network. Of the low-speed signal, multiple low-speed signals are multiplexed and transmitted as a high-speed signal to the backup transmission line of the transmitting side, and when a failure of the working transmission line of the receiving side is detected, the working transmission line of the receiving side is detected. The first demultiplexing unit that stops each low-speed signal that separates the high-speed signal and the high-speed signal from the backup transmission line on the receiving side are separated into multiple low-speed signals, and the multiple low-speed signals are multiplexed and transmitted as high-speed signals. Second multiplex for stopping each low-speed signal that is separated from the high-speed signal of the receiving-side backup transmission line when the high-speed signal received from the receiving-side backup transmission line is stopped. A separation part, and the first multi When the low-speed signal from the demultiplexing unit is stopped, the transmission of the low-speed signal multiplexed on the backup transmission path on the transmission side to the first demultiplexing unit is stopped, and the low-speed signal from the second demultiplexing unit is stopped. A signal addressed to itself is taken in from the inside, a signal other than that addressed to itself is returned to the second demultiplexing unit as a low speed signal, and when the low speed signal from the second demultiplexing unit stops, the first demultiplexing unit is stopped. A communication device having a switch unit for returning signals other than those addressed to itself in the low-speed signal from the device to the first demultiplexer as a low-speed signal. 12. The communication device according to claim 11, wherein a plurality of the first demultiplexing units, the second demultiplexing units, and the switch units are provided for each wavelength, and wavelength-multiplexed signals are transmitted and received. 13. A communication device, which is connected in a dual ring shape by working and protection transmission lines to form a communication network, when a failure of the working transmission line on the receiving side is detected, and on the working transmission on the receiving side. A communication device characterized in that, when a signal from a line stops, a signal addressed to itself is taken in from a backup transmission line on the receiving side and transmission of the signal to the working transmission line on the transmitting side is stopped. 14. In a communication device that constitutes a communication network by connecting in a dual ring shape with working and protection transmission paths having different signal flow directions, when a failure is detected in the working transmission path on the receiving side, the transmitting side Stop sending the signal to the backup transmission line of the receiver, take in the signal addressed to itself from the signals from the backup transmission line of the reception side, loop back the signals other than those addressed to the current transmission line of the transmission side, and protect the reception side A communication device, wherein when a signal from a transmission line is stopped, a signal other than its own among the signals from the active transmission line on the receiving side is returned to the active transmission line on the transmitting side.