JP2002262316A - Optical communication network node device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication network node system where a host management device can easily grasp a fault state and troubleshoot a cause to the fault by suppressing a huge amount of alarm notices caused at the same time from a plurality of node devices to the host management device on the occurrence of the fault in an optical signal. SOLUTION: An information processing section 107 is provided with a wavelength address map 111 that stores path information by each communication wavelength and an alarm/notice processing section 110 that makes an alarm notice to downstream nodes during communication by a prescribed format with the path information attached thereto when detecting a fault, analyzes alarm notices from other nodes received later after the detection of the fault, and suppresses the alarm notice beyond itself if the analysis of the alarm notice from another node indicates that it is an alarm the notice from an upstream node.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information suppression in an optical communication network device using a wavelength division multiplexing transmission method, and more particularly to an optical device for switching a transmission path without changing an optical signal in a node device for relaying an optical signal. The present invention relates to signal suppression in an optical communication network device using a switch.

[0002]

2. Description of the Related Art As a technique for realizing a large-capacity communication by multiplexing a plurality of lights having different wavelengths in one optical transmission line, WD is used.
M (Wavelength Division Mul)
ixing) technology. With the increase in network demand, examples of constructing a large-capacity network using this technology are increasing. However, when switching a transmission line in a node device that relays a multiplexed optical signal,
Rather than once converting an optical signal to an electrical signal and then switching, instead of using an optical switch to switch the transmission path without changing the optical signal, the size and cost of the node device can be reduced. The device that we have designed has appeared. An example of such a device is an optical cross-connect device.

In a network using an optical cross-connect device, when an electric signal is converted to an optical signal at a certain node, the optical signal is transmitted as it is at a relay node located intermediate the target node. However, since the optical signal remains unchanged, even if a failure occurs in the optical signal, the failure is detected by the terminal node that converts the optical signal into an electric signal, and the relay node cannot detect the failure. There was a problem that was left without. As a conventional technique for solving this problem, for example, Japanese Patent Laid-Open No. 2000-13
There is a technique disclosed in No. 8953.

FIG. 4 is a block diagram of the apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-138953. In the figure, an optical communication network node 911 includes a WDM coupler 902 and a WDM coupler 9 to which an optical signal from an optical transmission line 901 is input.
An optical coupler 903 to which an optical signal is input from the optical coupler 02, an optical switch network 904 for switching input light from the optical coupler 903, an optical receiver 905 for receiving light branched from the WDM coupler 902, and a branch from the optical coupler 903. Optical receiver 906 for receiving the transmitted light, an information processing device 907 for performing information processing in the node 911, an OAM which is an optical signal modulated with information on maintenance, operation and management of the network.
(Operation, Administratio
An optical transmitter 919 for transmitting n, and maintance signal light, and an optical coupler 915 for superimposing output light from the optical switch network 904 and output light from the optical transmitter 919. Output light from the optical coupler 915 is sent to the optical transmission line 916.

Next, the operation of the conventional apparatus disclosed in FIG. 4 will be described. The main signal light and the OA
M signal light is superimposed. The OAM signal light is separated by the WDM coupler 902 and received by the optical receiver 905. A part of the optical power of the main signal light is separated by the optical coupler 903 and sent to the optical receiver 906. The optical receiver 906 monitors the main signal light power (light reception level).
When the optical receiver 906 detects a failure in the main signal light, the information processing device 907 immediately performs a failure recovery operation. The optical switch network 904 is controlled to switch the failed optical transmission line to the spare optical transmission line, and includes information on the identifier of the failed optical transmission line and information on the spare optical transmission line used for failure recovery. The OAM signal light is transmitted from the optical transmitter 919. The OAM signal light is superimposed on the main signal light by the optical coupler 915 and transmitted to an adjacent node via the optical transmission line 916. The adjacent node performs a switching operation according to information included in the received OAM signal light. Further, in the adjacent node and one or more nodes connected to the adjacent node, the necessary switching operation is similarly performed according to the information included in the OAM signal light, and finally, the connection to the spare optical transmission line is performed. Complete the switch.

An optical communication network composed of a plurality of node devices using such an optical cross-connect device is often managed by a management device such as an OpS (Operation System). The management device sets and refers to the state of the node device, and performs processing relating to various alarms / notifications issued from the node regarding a state change or failure detection that has occurred in the node device. Further, there may be a higher-level management device that collectively manages a plurality of management devices.

FIG. 5 is a configuration diagram of an optical communication network composed of conventional node devices. An optical transmission line 930 is provided between the nodes 920 and 921, an optical transmission line 931 is provided between the nodes 920 and 922, an optical transmission line 932 is provided between the nodes 921 and 923, and an optical transmission line 932 is provided between the nodes 922 and 923. In the optical transmission path 933, an optical transmission path 934 is provided between the nodes 922 and 924, an optical transmission path 935 is provided between the nodes 923 and 924, and an optical transmission path 936 is provided between the nodes 923 and 925. An optical transmission line 937 is connected between the node and the node 926, and an optical transmission line 938 is connected between the node 924 and the node 926.
From the node 920 to the node 925, an optical path 940 is transmitted via the node 922 and the node 923 in this order.
From 0 to node 926, nodes 922, 924
, An optical path 941 is set. Also,
Each node is connected to the management device, and a failure detected by the node is notified to the management device as an alarm.

[0008] Here, consider a case where a failure occurs in which the transmission line 931 is disconnected. Although the optical path 940 and the optical path 941 pass through the transmission path 931, both optical paths are disconnected due to the cut of the transmission path 931. Therefore, among the nodes corresponding to the optical path, the transmission path 931
A node located closer to the end point of the optical path detects a failure of the main signal light. In FIG. 5, nodes 922,
Node 923, Node 925, Node 924, Node 9
26 detects a failure of the main signal light. When the node detects a failure in the main signal light, an alarm is notified to the management device.
The alarm is simultaneously notified from the five nodes to the management device.

[0009]

Since the conventional optical cross-connect device is constructed and connected as described above, a large number of alarms are simultaneously and frequently generated due to the interruption of one optical path.
For this reason, an alarm that cannot be grasped by the manager is output to the management device, and there is a problem that it is difficult for the management device to grasp the failure situation and identify the cause of the failure. Further, as the multiplexing of optical wavelengths progresses by the WDM technology, the number of optical paths affected when a failure occurs in an optical transmission line or a node increases, and the amount of alarms increases. It becomes more difficult to grasp the failure status and identify the cause of the failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems.
A large number of alarm notifications that occur simultaneously from a plurality of node devices to a higher-level management device are suppressed, and the management device can easily grasp the failure status and specify the cause of the failure.

[0011]

An optical communication network / node apparatus according to the present invention comprises: a wavelength address map for storing route information for each wavelength to be communicated;
An alarm notification processing unit that performs an earlier alarm notification to the downstream node in communication in a predetermined format with path information, and detects a failure, and then sends a later alarm notification from another node. By analyzing, if the subsequent alarm notification is an alarm notification from the upstream for the same fault, the alarm notification of its own destination is suppressed.

[0012] Furthermore, a timer is provided in the node device, and after a failure is detected, if there is no alarm notification from the upstream after a set time, the previous alarm notification is performed.

Still further, the node transmits A
A PS (Automatic Protection Switching) byte is used, and the route information of the wavelength address map is included in the APS byte.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a configuration of an optical communication network node device according to the embodiment of the present invention. Hereinafter, this optical communication network node device is abbreviated as a node. An optical cross-connect device can be used for the node. In FIG. 1, a node 100 inputs an optical signal from an optical transmission line 101 and outputs an optical signal to an optical transmission line 115. On the optical transmission line, OA
A plurality of optical signals having different wavelengths including the M signal light are superimposed. The input and output of the optical signal to the node 100 are 1
It is not limited to a book, and a plurality of inputs and outputs are possible, but for convenience of explanation, FIG. 1 shows one input optical signal and one output optical signal.

The node 100 also includes a WDM coupler 102, W, which branches the optical signal from the optical transmission line 101 for each wavelength.
An optical coupler 103 for partially branching optical power from an optical signal of one wavelength extracted by the DM coupler 102, an optical switch network 104 for switching the optical signal, a WDM coupler 10
First optical receiver 10 for receiving the OAM light branched in 2
5. Second receiving optical signal branched by optical coupler 103
Optical receiver 106, an information processing device 107 for performing information processing in the node 100, a management device interface 112 which is an interface with a management device for managing the node 100, an optical transmitter 113 for transmitting OAM light, an optical switch It comprises a WDM coupler 114 for combining a plurality of optical signals having different wavelengths output from the circuit network 104 and the optical transmitter 113. Further, the information processing device 107
Is an OAM that processes an OAM signal from the optical receiver 105.
A processing unit 108, an OAM processing unit 109 for performing processing for transmitting OAM light from the optical transmitter 113, and an alarm / notification processing unit for performing processing relating to an alarm or notification to be transmitted to the management device by an event occurring in the node 100. 110, a wavelength address map 111 for holding path information of an optical signal for each wavelength is included. Note that one set of the optical coupler 103 and the second optical receiver 106 is provided for each wavelength split by the WDM coupler 102, but only one set corresponding to one input optical signal is shown in FIG. .

FIG. 2A is a diagram showing an example of an optical communication network constituted by a plurality of nodes. Node 100
Constitutes an optical communication network together with the other nodes 123, 124, 125, 126, 127 and 128. The nodes are connected by the following optical transmission lines. The optical transmission line 101 connects the node 123 and the node 100, the optical transmission line 120 connects the node 123 and the node 124, the optical transmission line 119 connects the node 124 and the node 125, and the node 100
An optical transmission line 121 connects the node 10 and the node 125.
0 and the node 126 via the optical transmission line 115, the node 1
25 and the node 126 on the optical transmission line 122, between the node 125 and the node 127 on the optical transmission line 118, between the node 127 and the node 128 on the optical transmission line 119, and on the node 126 and the node 128. The connection is established by an optical transmission line 116. An optical path 140 is transmitted from the node 123 to the node 127 via the node 100 and the node 125 in this order.
An optical path 141 is set from the node 123 to the node 128 via the node 100 and the node 126 in this order. Each node is also connected to a node management device. The node 100 includes a management device 130 and a node 125.
Is the management device 131, and the node 127 is the management device 13
2 are connected. The management device is similarly connected to other nodes, but is not shown in FIG. FIG. 2B is a diagram illustrating the state of FIG. 2 stored in the wavelength address map 111.
It is a figure which shows the route information of the optical communication network of (a).

Next, the operation of the present invention will be described with reference to the operation when the transmission line 101 is disconnected. The optical path 140 and the optical path 141 pass through the transmission path 101, and both optical paths are cut by the disconnection of the transmission path 101. Light path 14
0 is disconnected, the optical path 14
The optical power input to the second optical receiver 106 corresponding to 0 is lost, and a failure of the main signal light used by the optical path 140 is detected. When detecting the failure of the main signal light, the information processing device 107 sends an alarm from the alarm / notification processing unit 110 to the management device 130 managing the node 100 via the management device interface 112.

The node 100 also uses OAM light to
The identifier of the failed optical path and the information necessary for setting the detour are transferred to the adjacent node. For information transfer, for example, SDH (Synchronous Digita) is used.
l Hierarchy) and SONET (Sync)
A transmission frame of a (Hronous Optical Network) system is used. SDH method and SONET
In the system, APS (Automatic Protect
In some cases, a byte for automatic switching, referred to as “tion switching” byte, may be used. The APS byte is, for example, an SOH (Section) in the transmission frame.
Overhead Head) includes two regions K1 and K2. Also in the present invention, the APS byte can be used for transferring the identifier of the failed optical path and the information necessary for setting the detour. FIG. 3 shows an example of K1 and K2 bytes in the present invention. The K1 byte is assigned a switching request code and an optical path code, and the K2 byte is assigned a source node ID and a status code.

The node 10 that has detected a failure in the optical path 140
0 refers to the wavelength address map 111 so that the optical path 140
It is determined that the node 127 is set as the end point via 0 and the node 125 in order. Information processing device 107
Then, the SF code indicating the occurrence of a failure is set in the K1 byte switching request code, and the optical path number is set as the optical path number.
Set the code meaning 0. In the K2 byte, a code indicating the node 100, that is, 0000 in this case, is set in the transmission source node ID with reference to the wavelength address map 111, and the RDI (Re
Set the position code for the "Move Defect Indication" code. The information processing device 107 sets the K
The information necessary for transmitting the OAM signal including the 1, K2 bytes
The wavelength address map 111 is processed by the AM processing unit 109.
The OAM light including the K1 and K2 bytes is transmitted from the optical transmitter 113 to the node 125, which is the node located next to the node 100 in the optical path 140, determined in step (1). The OAM light is combined with an optical signal of another wavelength by the WDM coupler 114 and transmitted to the optical transmission path 121 which is a transmission path to the node 125. By referring to the wavelength address map 111, optical transmission is also performed to the node 126 using the K1K2 byte including the optical path code 0001.

At the node 125, the optical signal of the optical path 140 does not reach the transmission line 101 because the transmission line 101 is cut off. Therefore, similarly to the node 100, the optical power input to the second optical receiver 106 at the node 125 is reduced. Gone,
A failure of the main signal light used by the optical path 140 is detected. When a failure of the main signal light is detected, the information processing device 107
Sends an alarm from the alarm / notification processing unit 110 to the management device 131 managing the node 125 via the management device interface 112 once.

Thereafter, the node 125 receives the OAM light transmitted from the node 100 by the optical receiver 105, and
The M processing unit 108 determines the contents of the K1 and K2 bytes included in the OAM light. From the code set in the K1 byte optical path number, it is determined that the APS byte is for the optical path 140, and the K1 byte switching request code is SF
Since the status code of the K2 byte is an RDI code, the failure is notified from a node on the starting side of the node 125 that is the own node among the nodes configuring the optical path 140. Determine. Further, since the code indicating the node 100 is set in the transmission source node ID of the K2 byte, it is determined that the node that has detected the failure is the node 100.

From the above operation, the node 125 determines that the cause of the failure of the optical path 140 detected by the optical receiver 106 is not between the node itself and the node 100. Then, the information processing device 107 in the node 125 controls the alarm / notification processing unit 110 to suppress the alarm notification to the management device 131, and the K1 and K2 bytes transmitted from the node 100 determined by the OAM processing unit 108. Is sent to the OAM processing unit 109 as it is, and the OAM processing unit 109
0, the wavelength address map 1
The OAM light including the K1 and K2 bytes is transmitted from the optical transmitter 113 to the node 127, which is the node located next to the node 125 in the optical path 140, determined in step 11. The OAM light is combined with an optical signal of another wavelength by the WDM coupler 114 and transmitted to the optical transmission line 118 which is a transmission line to the node 127.

The node 127 also receives the OAM light including the K1 and K2 bytes set in the node 100 in the same manner as the node 125, and issues an alarm notification to the management device 132 by the same operation as in the node 125. Deter. Similarly, for the optical path 141, the node 100
Detects a failure in the main signal light used by the optical path 141, and issues an alarm notification issued from the node 126 and the node 128 to each management device by the same operation as that of the optical path 140 described above. Deter.

As described above, when a failure occurs in an optical signal, the node on the optical path in which the failure has occurred on the failed optical path among the nodes that have detected the failure transmits the A in the OAM light.
Since the failure detection is notified to the end point of the optical path using the PS byte, and the node that has been notified of the failure detection suppresses the notification of the alarm, a plurality of nodes affected by the optical signal failure are notified. , It is possible to suppress a large number of alarm notifications that occur simultaneously and frequently, and it is easy to grasp the failure and specify the cause of the failure in the management device.

Embodiment 2 FIG. In the first embodiment described above, when the second optical receiver 106 detects a failure in the main signal light,
Since the information processing apparatus 107 immediately sends an alarm from the alarm / notification processing unit 110, the information processing apparatus 107 determines that the cause of the failure detected by the node does not exist between the own node and the adjacent node on the starting side of the optical path, and issues the alarm / notification. Until the notification of the alarm is suppressed by controlling the processing unit 110, the alarm is continuously transmitted to the management device. In the present embodiment, the second optical receiver 106
Does not immediately transmit an alarm issued to an external management device when detecting a failure of the main signal light, and does not immediately transmit the warning when the failure is detected, and transmits the warning after the alarm / notification processing unit 110 suspends for a certain period of time. The operation is shown.

In FIG. 2, when the transmission line 101 is disconnected,
The optical path 140 and the optical path 141 passing through the transmission path 101
Is disconnected. Then, as in the first embodiment, the node 1
At 00, no optical power input to the second optical receiver 106 occurs in the optical path 140, and a failure of the main signal light used by the optical path 140 is detected. When detecting the failure of the main signal light, the information processing device 107 attempts to send an alarm from the alarm / notification processing unit 110 to the management device 130. At this time, the alarm / notification processing unit 110 does not immediately transmit the alarm, but suspends the transmission of the alarm for a preset fixed time.
The length of the hold time is determined after the failure is detected on another node.
The time is set to a time required for information of the detected fault to be transmitted to the own node by the OAM light, with a slight margin added. For example, in this embodiment, it is 100 milliseconds. After the elapse of the suspension time, the alarm / notification processing unit 110 sends an alarm to the management device 130 managing the node 100 via the management device interface 112.

Node 10 that has detected a failure in optical path 140
0 is O including K1 and K2 bytes as in the first embodiment.
The AM signal light is determined by the wavelength address map 111,
The packet is transmitted to the node 125 which is the node located next to the node 100 in the optical path 140.

The node 125 detects the failure of the main signal light used by the optical path 140 similarly to the node 100 because the optical signal of the optical path 140 does not reach the transmission line 101 due to the disconnection of the transmission line 101. Upon detecting a failure of the main signal light, the alarm / notification processing unit 110 does not immediately issue an alarm, but suspends the transmission of the alarm for a preset suspension time.
The length of the hold time is determined after the failure is detected on another node.
Since the time required for the information of the detected fault to be transmitted to the own node by the OAM light is set to a time in which a slight margin is added, the node 125 determines that the node 100 is OAM light to optical receiver 105
To receive. The received OAM light is output to the OAM processing unit 108
Is used to determine the contents of the K1 and K2 bytes included in the OAM light. Here, similarly to the first embodiment, it is determined from the code set in the K1 byte optical path number that the APS byte is for the optical path 140, and that the K1 byte switching request code is SF code and the K2 byte Since the status code is the RDI code, it is determined that a failure has been notified from a node on the starting side of the node 125 that is the own node among the nodes configuring the optical path 140.

From the above operation, the node 125 determines that the cause of the failure of the optical path 140 detected by the optical receiver 106 is not between the node itself and the node 100. Then, the information processing device 107 in the node 125 controls the alarm / notification processing unit 110 so as not to issue an alarm notification to the management device 131 even after the elapse of the hold time. If the hold time has elapsed, the notification of the sending alarm is suppressed. The OAM processing unit 108 and the OAM processing unit 109 operate in the same manner as in the first embodiment with respect to the optical transmitter 1
13 transmits the OAM light including the K1 and K2 bytes.

The node 127 also receives the OAM light including the contents of the K1 and K2 bytes set in the node 100 in the same manner as the node 125, and operates in the same manner as the operation of the node 125 so that the management device is operated after the elapse of the hold time. 1
32 is not notified. Light path 141
Similarly, the node 126 and the node 128 do not issue an alarm notification to each management device after the elapse of the hold time. As described above, when a failure occurs in an optical signal, the alarm notification is suspended from when the failure is detected until the node suppresses the alarm notification based on the information of the APS byte in the OAM light. Therefore, it is possible to suppress a large number of alarm notifications simultaneously and frequently generated from a plurality of nodes affected by the optical signal failure, and to easily grasp the failure and specify the cause of the failure in the management device.

[0031]

As described above, according to the optical communication network / node apparatus of the present invention, the previous alarm notification with the route information is issued, and if there is a later upstream alarm notification, the earlier alarm notification is suppressed. As a result, there is an effect that a large amount of alarms are transmitted when a failure is detected, and the failure is easily identified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical communication network / node device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating an example of a network configuration including a plurality of nodes and information in an address map according to the first embodiment;

FIG. 3 is a diagram showing K1K2 bytes in APS bytes used in the first embodiment.

FIG. 4 is a configuration diagram of a conventional optical communication network device.

FIG. 5 is a network diagram of a conventional optical communication network device.

[Explanation of symbols]

100 optical communication network node, 107 information processing unit, 1110 alarm / notification processing unit, 111 wavelength address map.

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Claims (3)

[Claims] 1. A wavelength address map for storing path information for each wavelength to be communicated, and when a failure is detected, an earlier alarm notification is sent to the downstream node in communication in a predetermined format with the path information. An alarm notification processing unit for performing, after detecting the failure, analyze the subsequent alarm notification from the other node, if the subsequent alarm notification is an alarm notification for the same failure from upstream, An optical communication network characterized by suppressing the above-mentioned previous alarm notification.
Node device. 2. A method according to claim 1, wherein a timer is provided in the node device, and when a failure is detected, if there is no alarm notification from the upstream after a set time, the alarm notification is made earlier. 2. The optical communication network node device according to 1. 3. The node sends an APS (Au
tomatic ProtectionSwitching) bytes using the AP
2. The optical communication network node device according to claim 1, wherein the route information of the wavelength address map is carried in the S byte.