JPH11225118A - Node device and ring network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a node device capable of economically performing wavelength multiplexing of a large number of optical signals, and a failure of an optical fiber disconnection, an optical fiber cable disconnection, and a multiplexing device (ADM). However, we propose a ring network that has restoration ability. SOLUTION: The node device accommodates optical fibers 5-1 to 5-4 and 6-1 to 6-4 for transmitting a wavelength multiplexed optical signal. The node device includes optical switch units 9-1 to 9-4 for switching an optical transmission line for inputting / outputting an optical signal, and a wavelength separator 11- for separating a wavelength multiplexed signal from the optical switch unit.
2, 11-3, 11-5, and 11-8, and wavelength multiplexers 11-1 and 11 for wavelength-multiplexing an optical signal to the optical switch unit.
-4, 11-6, 11-7 and a multiplexer ADM provided between the wavelength demultiplexer and the wavelength multiplexer for demultiplexing, inserting, or regenerating and repeating optical signals of each wavelength.
And is provided. Also, a ring network is configured using a plurality of the node devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a node device and a ring network constituting a network, and more particularly to a node device for separating, inserting, or regenerating and repeating optical signals, and an optical fiber 1 connected to the node device. The present invention relates to a ring network in which optical signals of a plurality of wavelengths are connected by wavelength division multiplexing (WDM) optical fibers.

[0002]

2. Description of the Related Art As a prior art related to a typical ring network to which an optical fiber is applied in public communication,
For example, "Fiber Network Service Survivabilit
y, Tsong-Ho Wu, published by Artech House, 1992. "
A ring network called SHR (Self-Healing Ring) described in U.S. Pat.

A ring network using an optical fiber includes a plurality of add-drop multiplexers (hereinafter referred to as ADMs) and two or four ADMs for connecting them in a ring.
And an optical fiber. The ADM is a device that realizes insertion (add) of a signal into a ring, separation (drop) of a signal from the ring, and relaying (pass-through) of a signal flowing through the ring to a downstream side. Also, ADM
For example, in the case of a four-fiber type, a plurality of optical fibers connecting each other transmit traffic as active fibers, and the remaining two are used as spare fibers.

[0004] The above-mentioned conventional ring network has a recovery capability against an optical fiber disconnection, an optical fiber cable disconnection, and a failure of a multiplexer (ADM), and realizes recovery by line switching, loopback, and the like. doing. Also, the ring network according to the prior art is WD
M can also be applied. In this case, the network configuration is a two-fiber type, and by equivalently transmitting bidirectional optical signals of two wavelengths to each optical fiber, a four-fiber type ring network is equivalently realized. can do.

[0005]

In the ring network according to the prior art described above, when the number of wavelength multiplexing is further increased to increase the total transmission capacity of the ring, a multiplexer (ADM) for the number of wavelengths is required. However, there is a problem that the cost increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to make it possible to economically perform wavelength multiplexing of a large number of optical signals. An object of the present invention is to provide a ring network capable of recovering from a failure of a multiplexer (ADM).

[0007]

According to the present invention, an object of the present invention is to provide a node device in a network in which a plurality of node devices are connected by an optical transmission line using an optical fiber for transmitting a wavelength multiplexed optical signal. An optical switch for switching an optical transmission path for inputting and outputting an optical signal,
A wavelength separator for separating the wavelength multiplexed signal from the optical switch, a wavelength multiplexer for wavelength multiplexing the optical signal to the optical switch, and a wavelength separator provided between the wavelength separator and the wavelength multiplexer. This is achieved by including a multiplexer that separates, inserts, or regenerates and repeats optical signals of each wavelength.

Further, the above object is achieved by forming a ring network by connecting a plurality of node devices having the above-described configuration in a ring by an optical transmission line using an optical fiber for transmitting a wavelength multiplexed optical signal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a ring network using an optical fiber according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a ring network to which the present invention is applied, and FIG. 2 is a block diagram showing the configuration of a node device according to the first embodiment of the present invention. 1 and 2, reference numerals 1 to 4 denote node devices and 5-1.
5-4 are current optical fibers A, 6-1 to 6-4 are standby optical fibers A, 7-1 to 7-4 are current optical fibers B, 8-
1-8-4 are spare optical fibers B, 9-1-9-4 are optical switch sections, 10-1-10-8 are optical amplifiers, 11-1-1
11-8 is a wavelength division multiplexer (WDM), 12-1 to 12-12
-8 is a multiplexer (ADM), 13-1 to 13-8 are regenerators (REG), and 14 is an optical performance monitoring unit.

A ring network to which the present invention shown in FIG. 1 is applied includes node devices 1 to 4 and working optical fibers A5-1 to 5-4 and standby optical fiber A6-1 as optical transmission lines connecting them. 6-4, working optical fiber B7-1
7-8 and a bidirectional four-fiber optical ring network configured using spare optical fibers B8-1 to B-8-4. In the illustrated example, the signal flow of the working optical fiber A is counterclockwise, and the signal flow of the standby optical fiber B is clockwise. In the illustrated example, a ring network is configured using four node devices, but more node devices can be used. In addition, it is assumed that optical signals of wavelengths λ1 to λ4 are multiplexed and transmitted in the optical fiber connecting the node devices.

Although the node device according to the first embodiment of the present invention shown in FIG. 2 is an example of the node device 1, the node devices 2 to 4 have the same configuration. Each node device is composed of a plurality of 1 × 2 optical switches for inputting / outputting an optical signal, and an optical switch unit 9-1 accommodating an optical fiber.
To 9-4, an optical amplifier and a WDM symmetrically arranged between two optical switches, an ADM and a REG interposed between the two WDMs, and an optical performance monitoring unit 14. It is configured as shown in FIG.

The WDM is a well-known device having a function of a wavelength multiplexer and a wavelength separator for multiplexing or demultiplexing a plurality of optical signals having different wavelengths, and the ADM is a device for separating and inserting optical signals. Or a well-known multiplexing device having a function of performing reproduction relay. Further, the REG is a known device having only a function of reproducing and repeating an optical signal. The 1 × 2 optical switches constituting the optical switch units 9-1 to 9-4 are indicated by reference numerals in the 900th order in FIG.

Next, the operation of the node device according to the first embodiment of the present invention configured as described above will be described with reference to FIG.

The optical signal input from the working optical fiber A5-4 is transmitted to the 1 × 2 optical switch 92 in the optical switch section 9-2.
2, 921, and amplified by the optical amplifier 10-2, then demultiplexed in the WDM 11-2 into wavelengths λ1, λ2, λ3, and ADM12-1, ADM12-2, and ADM12-2, respectively.
It is input to the ADM 12-3. ADM12-1, ADM
The optical signals of wavelengths λ1, λ2, λ3 input to each of the ADM 12-2 and the ADM 12-3 are thereafter converted to the WDM 11-1.
After being multiplexed in the optical amplifier 10-1, the signal is amplified by the optical amplifier 10-1 and the 1 × 2 optical switch 912 in the optical switch unit 9-1.
911 to the current optical fiber A5-1 from the node device 1.
Is output to

The optical signal from the working optical fiber B7-1 is also output to the working optical fiber B7-4 in the same manner as described above, but the path is through the optical switches 931 and 9 of the optical switch section 9-3.
32 → Optical amplifier 10-5 → WDM11-5 → ADM12
−5, 12−6, 12−7 → WDM 11−6 → optical amplifier 10−6 → optical switches 941 and 9 of the optical switch unit 9-4
42. The path of the optical signal from the spare optical fiber A6-1 is the optical switch 915 of the optical switch unit 9-1,
916 → optical amplifier 10-3 → WDM11-3 → REG1
3-1, 13-2, 13-3 → WDM 11-4 → optical amplifier 10-4 → optical switch 925 of optical switch section 9-2,
926 → standby optical fiber A6-4, and the path of the optical signal from the standby optical fiber B8-4 is changed to the optical switch section 9-4.
Optical switches 946 and 945 → optical amplifier 10-8 → WD
M11-8 → REG13-5, 13-6, 13-7 → W
DM11-7 → optical amplifier 10-7 → optical switch section 9-3
Optical switches 936 and 935 → spare optical fiber B8-1
Becomes

The ADM 12-4 is a backup ADM, and the wavelength λ4 passing therethrough is a backup wavelength. And A
When a failure (device failure) occurs in one of the ADMs among the DMs 12-1 to 12-3, the failed ADM is referred to as an ADM.
The signal is switched to 12-4, and the optical signal of the wavelength λ4 is used. Similarly, the ADM 12-8 and the optical signal of the wavelength λ4 passing therethrough, the REG 13-4 and the optical signal of the wavelength λ4 passing therethrough, R
The EG 13-8 and the optical signal of the wavelength λ4 passing therethrough are also spares in the event of a device failure.
Will be described later.

Each of the optical switch units 9-1 to 9-4 has optical switches 911 to 91 provided therein.
6, 921 to 926, 931 to 936, 941 to 946
Thus, as described later, when the working optical fiber is cut or the cable is cut, the path of the optical signal is switched so that the optical signal is bypassed from the working optical fiber to the spare optical fiber.
At this time, the spare optical fibers 6-1, 6-4, 8-1, 8
The signal flow of -4 can take both clockwise and counterclockwise directions.

In the above description, the optical switch units 9-1 to 9-
The configuration of No. 4 need not be limited to the example shown in FIG. 2. For example, the optical switch unit 9-2 is configured such that the working optical fiber A5-4 is connected to the optical amplifier 10-2 during normal operation, and the The spare optical fiber A6-4 is an optical amplifier 10-2.
As long as it is connected, any other configuration may be used. The optical switch unit 9-1 also connects the output of the optical amplifier 10-1 to the working optical fiber A5-1 during normal operation,
Other configurations may be used as long as the standby optical fiber A6-1 and the working optical fiber A5-1 can be connected at the time of loopback. As for the configurations of the optical switches 9-3 and 9-4, other configurations may be used as long as they have the same functions as the optical switches 9-1 and 9-2, respectively.

The optical performance monitoring unit 14 monitors the monitoring line 1 indicated by a dotted line.
5 monitors optical components such as optical amplifiers, WDMs, and optical switches, and also monitors signals. The means include optical power detection, S / N ratio monitoring, and the like.

FIG. 3 is a block diagram showing the configuration of the node device according to the second embodiment of the present invention. In FIG.
Reference numerals 9-5 and 9-6 denote optical switch units.
Is the same as The node device according to the second configuration example shown in FIG. 3 has the same configuration as that of FIG. 2 except for the configuration of the optical switch unit and the position of the optical amplifier, and the operation is the same as that of FIG.

That is, in the node device shown in FIG. 3, the optical amplifier is arranged so as to directly accommodate the optical fiber, and the optical switch unit 9-5 is replaced with the optical switch units 9-1 and 9 in FIG.
-3, and a function of connecting between the working backup optical fibers that perform bidirectional signal transmission. Similarly, the optical switch unit 9-6 is provided with the functions of both the optical switch units 9-2 and 9-4 in FIG.
It is configured to have a function of connecting between the working backup optical fibers that perform bidirectional signal transmission.

As will be described later, when the node device shown in FIG. 3 is used, the signal flow of the spare optical fibers 6-4 to 6-1 is clockwise, and the signals of the spare optical fibers 8-1 to 8-4 are clockwise. Is fixed in a counterclockwise direction. Thereby, the direction of the flow of the optical signal in the working optical fibers 5-1 to 5-4 is counterclockwise, and the working optical fibers 7-4 to
The direction of the optical signal flow in 7-1 is clockwise.

The above-described embodiment of the present invention employs a current AD.
M, 3 working wavelengths, 1 spare ADM
The base and the spare wavelength are set to one wavelength, but if there are a plurality of ADMs and wavelengths, and the spare ADM and wavelength shared by these, the number of working ADMs, the number of wavelengths, the number of spare ADMs,
The ratio to the number of wavelengths may be any number, and in general, N
As a positive integer can be N: 1. In the above description, the spare optical fiber is not ADM but RE.
G is used, but because REG is cheaper than ADM, even if the number of wavelengths of WDM increases,
This is because it is cheaper than preparing the number of wavelengths using M. Of course, it is assumed that the optical switch unit is sufficiently inexpensive.

FIGS. 4 to 6 show the first and second embodiments of the present invention.
FIG. 9 is a diagram for explaining a method of restoring an optical fiber disconnection failure and a cable disconnection failure by an optical switch unit when a ring network is configured using the node device according to the embodiment of the present invention, and then refer to FIGS. And how to recover from the failure.

FIG. 4 shows a working optical fiber 5-1 between the node device 1 and the node device 2 on the ring network using the node device according to the first embodiment described with reference to FIG. FIG. 4 is a diagram for explaining a recovery method (span switching method) in the case where is disconnected.
In FIG. 4, the WDM and AD of the node device shown in FIG.
Reference numeral 30 denotes a portion constituted by M and an optical amplifier.

In FIG. 4, during normal operation, the node device 1
The optical switch units 9-1 to 9-4 do not perform switching,
The working optical fiber A5-4 and the working optical fiber A5-1 are connected, and the spare optical fiber A6-4 and the spare optical fiber A6 are connected.
-1, the working optical fiber B7-1 and the working optical fiber B7-4 are connected, and the spare optical fiber B8-4 and the spare optical fiber B8-1 are connected. Node device 2
Similarly, each of the optical switch units No. to No. 4 does not switch, and similarly to the case of the node device 1, optical fibers at both ends of each node device are connected.

Now, it is assumed that a failure occurs in which the working optical fiber A5-1 for transmitting a signal from the node device 1 to the node device 2 is disconnected. At this time, the optical switch unit 9-1 of the node device 1 switches the working optical fiber A5-1 to the spare optical fiber A6-1 as indicated by 50. As a result, the optical signal that should have been output from the node device 1 to the working optical fiber A5-1 is bypassed to the standby optical fiber A6-1. In the downstream node device 2, the optical switch unit 9-2 replaces the working optical fiber A5-1 with the optical signal from the protection optical fiber A6-1 and replaces the working optical fiber A5-1 with the working optical fiber A.
Switching is performed as indicated by 51 so as to output to the side of 5-2. As a result, the optical signal of the standby optical fiber A6-1 is output from the output side of the node device 2 to the working optical fiber A6-1.
It will be detoured to 5-2.

As described above, communication between the node device 1 and the node device 2 is performed using the spare optical fiber A6-1. As a result, the failure of the optical signal interruption due to the interruption of the working optical fiber A5-1 has been restored. Similarly, when the working optical fiber between the node device 2 and the node device 3, between the node device 3 and the node device 4, or between the node device 4 and the node device 1 is disconnected, the failure is also generated. Can be restored.

In the case of the example described above, since no failure of the optical fiber has occurred at any place other than between the node device 1 and the node device 2, the optical switch unit 9-1 of the node device 1 The optical switch units of the respective node devices other than the optical switch unit 9-2 of the node device 2 are not switched. In the case of the configuration of the node device in the example described, the direction of the signal in the spare optical fiber is the same as the direction of the signal in the working optical fiber.

FIG. 5 shows a working optical fiber between the node device 1 and the node device 2 on the ring network using the node device according to the second embodiment of the present invention described with reference to FIG. It is a figure explaining the recovery method (span switching system) when 5-1 is disconnected. In FIG. 5, the WD of the node device shown in FIG.
The part composed of M and ADM is indicated by reference numeral 34.

In FIG. 5, during normal operation, the node device 1
The optical switch units 9-5 and 9-6 do not perform switching,
The working optical fiber A5-4 and the working optical fiber A5-1 are connected, and the spare optical fiber A6-4 and the spare optical fiber A6 are connected.
-1, the working optical fiber B7-1 and the working optical fiber B7-4 are connected, and the spare optical fiber B8-4 and the spare optical fiber B8-1 are connected. Node device 2
Each of the optical switch units No. to No. 4 does not perform switching similarly, and connects the optical fibers at both ends of the node device as in the case of the node device 1.

Now, it is assumed that a failure occurs in which the working optical fiber A5-1 for transmitting a signal from the node device 1 to the node device 2 is disconnected. At this time, the optical switch unit 9-5 of the node device 1 switches the working optical fiber A5-1 to the spare optical fiber B8-1 as shown by 52. As a result, the optical signal that should be output from the node device 1 to the working optical fiber A5-1 is bypassed to the standby optical fiber B8-1. Also, in the downstream node device 2, the optical switch section 9-6 transmits the optical signal from the standby optical fiber B8-1 in place of the active optical fiber A5-1 to the active optical fiber A8.
The output is switched to the side of 5-2 as shown in FIG. Accordingly, the optical signal of the standby optical fiber B8-1 is output from the output side of the node device 2 to the working optical fiber A8.
It will be detoured to 5-2.

As described above, communication between the node device 1 and the node device 2 is performed using the spare optical fiber B8-1. As a result, the failure of the optical signal interruption due to the interruption of the working optical fiber A5-1 has been restored. Similarly, when the working optical fiber between the node device 2 and the node device 3, between the node device 3 and the node device 4, or between the node device 4 and the node device 1 is disconnected, the failure is also generated. Can be restored.

In the case of the above-described example, since no failure of the optical fiber has occurred at any place other than between the node device 1 and the node device 2, the optical switch section 9-5 of the node device 1 The optical switch units of each node device except the optical switch unit 9-6 of the node device 2 are not switched. In the case of the configuration of the node device in the example described, the direction of the signal in the spare optical fiber is opposite to the direction of the corresponding signal in the working optical fiber.

FIG. 6 shows a cable (working optical fiber A5-1, working optical fiber B7-1, spare optical fiber A6) between the node device 1 and the node device 2 on the ring network using the node devices 1-4. -1, spare optical fiber B
8A and 8B are diagrams for explaining a recovery method (loopback switching method) in the case where (8-1) is disconnected. In addition,
In the case of this example, the configuration of each node device may be any of the node devices described with reference to FIGS.

In FIG. 6, during normal operation, each node device does not perform switching by the optical switch unit as described with reference to FIGS. 4 and 5, and connects optical fibers at both ends of the node device.

Now, it is assumed that a fault occurs in which the cable including all the optical fibers between the node device 1 and the node device 2 is disconnected. When the cable is disconnected, the optical switch on the node device 2 side of the node device 1
The optical signal of the working optical fiber A5-1 is switched to the spare optical fiber B6-4 as shown in FIG. 54 so that 5-1 is turned back to the spare optical fiber B6-4. The optical switch on the node device 1 side of the node device 2 replaces the spare optical fiber A6-1 with the working optical fiber A5-.
The optical signal of the spare optical fiber A6-1 is switched to the working optical fiber A5-2 so as to be turned back to the side 2 as shown in FIG.

That is, when the cable is cut between the node device 1 and the node device 2, the node device 1 returns from the working optical fiber to the spare optical fiber, passes through the node device 4 and the node device 3, and returns to the node device 2. By returning from the spare optical fiber to the working optical fiber again, communication can be performed. The same applies when the cable between the node device 2 and the node device 3, the cable between the node device 3 and the node device 4, and the cable between the node device 4 and the node device 1 are disconnected. In the case of the example shown in FIG. 6, the direction of the signal in the spare optical fiber is opposite to the direction in the working optical fiber.

FIG. 7 is a block diagram showing a configuration of a node device according to the third embodiment of the present invention. The example shown in FIG. 7 corresponds to the WDM, ADM, and WDM of the node device shown in FIGS.
Only the portion including the REG is shown, and the arrangement and configuration of the optical switch and the optical amplifier may be the same as those shown in FIGS. This example is shown as a configuration example of the node device 2 in FIG. In this example, extraction and insertion of an optical signal from a node device to an external terminal or the like will be described.

The node device shown in FIG. 7 separates only the optical signal of wavelength λ1 from the working optical fiber A5-1 70-2,
Only the optical signal of wavelength λ1 is inserted 70-3 into the working optical fiber A5-2. Similarly, the working optical fiber B7
-2, only the optical signal of wavelength λ1 is separated 70-4, and only the optical signal of wavelength λ1 is inserted into the working optical fiber B 70
-1. Therefore, A provided in this node device
DM is an ADM 12-9 of wavelength λ1 that performs separation and insertion,
12-13 and the ADMs 12-9 and 12-1 having the wavelength λ4 to be used as spares when the ADMs 12-9 and 12-13 fail.
6, and the optical signals of the wavelengths λ2 and λ3 are REG12−
After passing through 10, 12-11, 12-14, and 12-15, separation and insertion are not performed in this node device. That is, in the node device of this example, the optical signals that can be separated and inserted are limited to only the optical signal of the wavelength λ1 or the optical signal of the wavelength λ4 which is a spare optical signal.

The node device having the configuration described above uses the A
The number of DMs can be reduced, and the cost of the device can be reduced.

FIG. 8 is a block diagram showing the configuration of a ring network incorporating the node device according to the third embodiment of the present invention described with reference to FIG. In this ring network, the node devices 2 and 4 are configured as shown in FIG. 8, the node device 2 separates and inserts only the optical signal of the wavelength λ1, and the node device 4 separates and inserts the optical signals of the wavelengths λ2 and λ3. Things.

The node device 4 in the illustrated example has a wavelength λ3
The optical signals of wavelength λ2 are selected by the optical switches 900 and 901 in the working optical fibers A5-3 and 5-4 to be separated, inserted, or passed. And optical switches 902, 9 in the working optical fibers B7-4, 7-3.
With 03, it is possible to select whether to separate, insert, or pass. That is, the node device 4 can separate and insert only the optical signal of the wavelength λ3,
It is also possible to separate and insert both wavelengths λ2 and λ3.

Each node device of the ring network shown in FIG. 8 has an arrangement and configuration of an optical switch and an optical amplifier.
Although shown as the first configuration example described with reference to FIG. 2, it may be the same as the second configuration example described with reference to FIG. Also, the node devices 1 and 3 can be configured similarly to the node devices 2 and 4.

FIG. 9 is a diagram for explaining a method of recovering from an ADM failure, which will be described below. The configuration shown in FIG. 9 corresponds to the WDM 11 of the node device shown in FIGS.
-1, 11-2, and ADMs 12-1 to 12-4.

In FIG. 9, it is assumed that a failure has occurred in the ADM 12-1. Then, the ADM 12-1 has the wavelength λ.
One optical signal cannot be electrically separated and inserted, and the use of the optical signal of the wavelength λ1 becomes impossible. Each ADM
Have an error detection function, and when a certain ADM fails, the ADM is switched to the spare ADM by the switching control line 60, and at the same time, the wavelength of the optical signal to be used is also switched to the spare wavelength λ4.

Therefore, in the case described above, the ADM 12-1 detects an error and switches the process of separating and inserting a signal to be performed by the ADM 12-1 to the spare ADM 12-4.
The wavelength used is also the spare wavelength λ4. ADM12
-2, when the ADM 12-3 fails, the switching is performed in the same manner. When the ADM is switched to the backup ADM 12-4 in one node device, the backup AD is also performed in the other node devices constituting the ring network.
Switching to M is performed, and the wavelength used is also switched to use λ4.

FIG. 10 shows a spare AD using the spare wavelength λ4.
FIG. 13 is a diagram illustrating a configuration example in which a maintenance ADM that is used by switching the ADM during ADM maintenance is added separately from M12-4.

The example shown in FIG. 10 is different from the example shown in FIG. 9 in that the maintenance ADM 12-1 uses the maintenance wavelength λ5.
This is an example in which No. 7 is added. In FIG. 10, for example, AD
It is assumed that M12-2 cannot be used for maintenance and inspection. In this case, if the maintenance ADM 12-17
If the ADM 12-1 is not provided, the ADM 12-2 is normally switched to the backup ADM 12-4 by the switching control line 60.
The failure of the DM 12-1 cannot be remedied. FIG.
In this case, even in such a case, even if a device failure occurs during maintenance and inspection, the device can be remedied.

That is, the example shown in FIG.
M12-17, ADM that is going to perform maintenance,
For example, the ADM-2 is switched to the maintenance ADM 12-17. As a result, during maintenance and inspection of ADM-2, AD
The communication using M-2 is switched to the maintenance ADM 12-17, and can be continued using the optical signal of the wavelength λ5. Even if the ADMs 12-1 and 12-3 fail, the communication can be continued. Can be switched to the ADM 12-4 for relief.

When the ADM is switched to the ADM 12-17 for maintenance in one node device, the ADM for maintenance is also switched in the other node devices constituting the ring network, and the wavelength used is λ5. Can be switched to use The configuration shown in FIG. 10 can be applied to the configuration examples of the node devices described with reference to FIGS. 2, 3, and 7.

FIG. 11 is a block diagram showing a configuration example of a network system configured by connecting a plurality of ring networks, and FIG. 12 is a block diagram showing a configuration example of a connection node device connecting the ring networks. . 11 and 12, 100 to 104 are ring networks, 201 to 204 are connection node devices, 30
1 to 304 are optical cross-connect devices, 401 to 404 are digital cross-connect devices, 501 to 504 and 60
1 to 604 are node devices.

The ring networks 100 to 104 constituting the network system shown in FIG. 11 may be ring networks including the node devices according to the embodiments of the present invention described above, or may be ADMs.
It may be another type of ring network using a node device configured with. The network system shown in FIG.
0 are connected to the ring network 100 and the ring networks 101 to 104, respectively.

Each of the connection node devices is composed of node devices constituting each ring network and an optical cross-connect device for connecting these. That is,
The connection node device 201 is configured by connecting the node device 501 of the ring network 100 and the node device 601 of the ring network 101 by the optical cross-connect device 301. The connection node device 202 is connected to the node device 502 of the ring network 100 and the ring device. The optical cross-connect device 3 is connected to the node device 602 of the network 102.
02. Similarly, the connection node device 203 is a node device 5 of the ring network 100.
03 and the node device 603 of the ring network 103 are connected by an optical cross-connect device 303.
0 and the node device 604 of the ring network 104 are connected by an optical cross-connect device 304. Each of the optical cross-connect devices 301 to 304 further includes a digital cross-connect 40.
1 to 404, respectively.

In FIG. 12 showing the configuration of a connection node device 201 for connecting between ring networks, ring networks 100 and 101 are ring networks configured using the node devices described with reference to FIG. 2 or FIG. . The configuration of the node devices 501 and 601 included in the connection network 201 may be any of the node devices having the configurations described with reference to FIGS.

Now, it is assumed that a signal is transmitted from a certain node device of the ring network 100 to a certain node device of the ring network 101. At this time, the node device 501 on the ring network 100 side in the connection node device 201 transmits the OC-192 (10 Gb /
s) The signal is separated, divided into low-speed signals in OC-12 (600 Mb / s) or OC-48 (2.5 Gb / s) units, and the optical fiber is switched in the optical cross-connect device 301 for each destination. Ring network 10
The OC-192 (10 Gb /
s) The signal is converted and inserted into a unit signal, and the signal reaches a target node device.

A signal passing through the optical cross-connect device 301 is transmitted to the digital cross-connect device 401 by the OC-12 / OC-48, and is subjected to optical / electrical conversion and line editing, and then DS-3 (50 Mb / s) or DS-1 (1.5
Mb / s) and distributed to various users. Signals in the ring networks 100 and 101 and signals between the OADMs 700 and 701 and the optical cross-connect device 301 are OC-192 and OC-4.
8, OC-12, other signals, for example, AT
It may be an M signal or the like.

[0059]

As described above, according to the present invention, wavelength multiplexing can be expanded economically, and the capability of recovering from optical fiber disconnection, optical fiber cable disconnection, and failure of a multiplexing device (ADM) can be achieved. Can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a ring network to which the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a node device according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a node device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a recovery method when a working optical fiber is cut on a ring network using the node device described with reference to FIG. 2;

FIG. 5 is a diagram illustrating a recovery method when a working optical fiber is cut on a ring network using the node device described with reference to FIG. 3;

FIG. 6 is a diagram illustrating a recovery method when a cable including all optical fibers is disconnected on a ring network using the node device described with reference to FIG. 2 or FIG.

FIG. 7 is a block diagram illustrating a configuration of a node device according to a third embodiment of the present invention.

8 is a block diagram illustrating a configuration of a ring network incorporating the node device described with reference to FIG. 7;

FIG. 9 is a diagram illustrating a recovery method when an ADM fails.

FIG. 10 is a diagram showing a case in which ADM is maintained at the time of ADM maintenance separately from a standby ADM.
FIG. 13 is a diagram illustrating a configuration example of a node device to which a maintenance ADM used by switching DMs is added.

FIG. 11 is a block diagram illustrating a configuration example of a network system configured by connecting a plurality of ring networks to each other.

FIG. 12 is a block diagram illustrating a configuration example of a connection node device that connects between ring networks.

[Explanation of symbols]

 1-4 Node device 5-1-5-4 Working optical fiber A 6-1-6-4 Spare optical fiber A 7-1-7-4 Working optical fiber B 8-1-1-8-4 Spare optical fiber B 9 -1 to 9-6 Optical switch section 10-1 to 10-8 Optical amplifier 11-1 to 11-8 Wavelength separation multiplexer (WDM) 12-1 to 12-8 Multiplexer (ADM) 13-1 to 13 -8 Regenerative repeater (REG) 14 Optical performance monitoring unit 100-104 Ring network 201-204 Connection node device 301-304 Optical cross-connect device 401-404 Digital cross-connect device 501-504, 601-604 Node device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04B 10/02 (72) Inventor Yasushi Sawada 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd. ) Inventor Yasuyuki Fukashiro 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref.Hitachi, Ltd.Information and Communication Division of Hitachi, Ltd. (72) Inventor Yukio Hayashi 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa, Japan (72) Inventor Tsuneo Nakata 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Inventor Hisayuki Nukawa 216, Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd.

Claims (10)

[Claims] 1. A node device in a network in which a plurality of node devices are connected by an optical transmission line using an optical fiber for transmitting a wavelength-division multiplexed optical signal, a first light for switching an optical transmission line input to the node device. A switch unit, a wavelength separator for separating the wavelength multiplexed signal from the first optical switch unit, and a multiplexer for separating, inserting, or regenerating and repeating optical signals of each wavelength separated by the wavelength separator. A wavelength multiplexer for multiplexing the optical signals of the respective wavelengths output from the multiplexer, and a second optical switch unit for switching an optical transmission line for outputting the wavelength multiplexed signal from the wavelength multiplexer. A node device characterized by being performed. 2. A multiplexing apparatus for separating, inserting, or regenerating and repeating optical signals, has an error detection function, and has N active (N ≧ 1 integer) and one standby system. 2. The node device according to claim 1, wherein the node device has an N: 1 configuration and switches to a standby device in the own node device when a failure occurs in the active multiplexing device. 3. The multiplexing device for demultiplexing, inserting, or regenerating and relaying an optical signal further includes a multiplexing device for maintenance. 3. The node device according to claim 2, wherein switching to a device for use is performed. 4. The node device according to claim 1, wherein the optical switch unit includes a plurality of 1 × 2 type optical switches. 5. A ring comprising a plurality of node devices according to any one of claims 1 to 4 connected in a ring shape by an optical transmission line using an optical fiber for transmitting a wavelength multiplexed optical signal. network. 6. The optical transmission line includes two working optical transmission lines in which a plurality of optical signals of different wavelengths are multiplexed and the transmission directions of the optical signals are opposite to each other, and the respective standby systems. 2
6. The ring network according to claim 5, wherein the ring network is constituted by four optical transmission lines. 7. When the node device has a standby multiplexing device and is switched to a standby device in place of the active device, the standby multiplexing device is also used in all other nodes in the network. The ring network according to claim 5, wherein the switching is performed simultaneously. 8. The maintenance multiplexing device in all of the other nodes in the network when the node device includes a maintenance multiplexing device and is switched to a maintenance device instead of the active system device. The ring network according to claim 5, wherein the switching is performed simultaneously. 9. The optical switch unit, when an active optical transmission line failure occurs between a source node device and a destination node device of an optical signal, sets the active optical transmission line to a standby optical transmission line. 9. The ring network according to claim 6, wherein switching is performed. 10. The optical switch unit according to claim 1, wherein when an optical transmission path between the source node device and the destination node device of the optical signal fails, the source and destination node devices
9. The ring network according to claim 6, wherein the active optical transmission line is switched to a standby optical transmission line in a direction opposite to the direction of the optical signal in the optical transmission line.