JPH077522A - Node bypass reporting method - Google Patents

Abstract

PURPOSE:To improve the efficiency of maintenance operations by discriminating bypass caused by the fault of an adjacent node corresponding to a detected reception address at a ring-shaped network and reporting the bypass to all the nodes. CONSTITUTION:Respective nodes A, B and C respectively transmit/receive address report packets through optical fibers 3-1 to 3-6 at suitable time intervals. Each node compares a transmission address loaded on the received report packet with the address of the upstream side adjacent node previously stored in the present node. When those addresses are the same as the compared result, it is judged that the network is normal but when they are different, it is judged that the upstream side adjacent node is bypassed, and the generation of bypass is reported to all the other nodes by packets. Thus, all the nodes can speedily grasp the generation of faults at the other nodes and enable required correspondent processing, and efficient dealing is enabled for the maintenance operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring type network in which a plurality of nodes are connected to each other by a transmission line so that each node can be bypassed, and when a node is bypassed, The present invention relates to a node bypass notification method for finding out that fact in an adjacent node and notifying other nodes including the bypassed node of that fact.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional ring network without a bypass function. In the figure, (1-1) to (1-5) are nodes AE and (2-
1) to (2-5) are transmission lines. In such a network, if the node A (1-1) fails or the transmission line (2-1) is disconnected, the node B
In (1-2), a failure can be easily detected due to a stop, an abnormality or the like of the reception signal from the node A (1-1). For this reason, it was easy to notify other nodes or maintenance personnel of the failure state and to deal with it.

FIG. 1 is a block diagram showing a ring network having a bypass function. In the figure, (1-
1) to (1-3) are nodes A to C and (4-1) to (4-).
3) is an optical accessor, (3-1) to (3-6) are optical fibers connecting the optical accessor and a node, and (5-1) to (5-).
3) is an optical fiber for connecting the optical accessors.

Here, the optical accessor (4-1) divides the optical signal from the optical fiber (3-1) into two, and divides the optical signal into the optical fiber (3-).
2) and (5-2), and the optical signal from the optical fiber (5-1) is divided into two and output to the optical fibers (3-2) and (5-2). Therefore, the optical signal from the node A (1-1) reaches the node B (1-2) through the optical fiber (3-1), the optical accessor (4-1) and the optical fiber (3-2).

The optical signal from the node C (1-3) includes an optical fiber (3-5), an optical accessor (4-3), an optical fiber (5-1), an optical accessor (4-1), The node B is reached through the optical fiber (3-2). Here, the loss in the optical fiber (5-1) is calculated as follows.
6) and (3-1) are set to be larger than the sum of the losses in node B (1-2), node A
The optical signal intensity from (1-1) is increased and the node C (1-
The optical signal intensity from 3) can be set small.

With this setting, the node B (1-
In 2), when normal, the signal from the node A (1-1) is received, the failure of the node A (1-1), the optical fiber (3-
At the time of disconnection 1) or the like, a signal from the node C (1-3) is received, and a highly reliable network can be constructed in which the failure location is automatically bypassed when the node, the optical fiber, or the like fails.

[0007]

However, in such a ring type network having a bypass function, even if the transmission part of a node fails, the node is bypassed and substantially cannot transmit. However, there is a problem that it is inconvenient because the data is continuously transmitted without knowing the fact.

An object of the present invention is to provide a ring-type network connected in a ring shape by an optical transmission line via an optical accessor having a function of bypassing a plurality of nodes,
When a failure occurs between the node's transmitter or the node's transmitter and the optical accessor and the node is bypassed, another node can detect it and notify the node accordingly. It is an object of the present invention to provide such a node bypass notification method capable of constructing a highly reliable network, enabling quick detection and repair of a failure point, and solving the above maintenance problem.

[0009]

In order to achieve the above object, according to the present invention, in a ring type network in which a plurality of nodes are connected to each other by a transmission line to form a ring shape so that each node can be bypassed, The node is provided with a storage unit for the address of the adjacent node and a comparison unit for comparing the node address stored in the storage unit with the received node address.

[0010]

In the above ring network, when a certain node is bypassed due to a failure or the like, the address of the bypassed node does not arrive at the downstream adjacent node, and another node is bypassed. From the place where the address arrives and is received, the adjacent node on the downstream side uses the comparison means to compare the address of the adjacent node stored in the storage means with the received address of another node and make a difference. Then, the existence of the bypassed node is known, and the fact is notified to other nodes including the bypassed node. As a result, it becomes possible to quickly find and repair a failure point, and a maintenance problem can be solved.

[0011]

EXAMPLES Next, examples of the present invention will be described. The configuration of the network used in the description is that shown in FIG.

FIG. 2 is an explanatory diagram showing a configuration example of a packet transferred on the network. In FIG. 2, (6-
1) is a packet header part, (6-2) is a packet information part (DATA), (6-3) is a control information part (FA) for performing packet access control, and (6-4) is a destination node. The address part (AS), (6-5) is the address part (AD) of the transmitting node, and (6-6) is the type part (PI) of this packet. The packet type section (PI) is for identifying whether this packet is a packet carrying normal information or an address notification packet for notifying the downstream adjacent node of its own node address.

In FIG. 1, nodes A (1-1), B
Each of (1-2) and C (1-3) transmits the address notification packet at an appropriate time interval. Also, when each node receives a packet, the packet type (P
I) is checked, and if it is an address notification packet, the sending node address (AD) contained therein is compared with the address of the upstream adjacent node previously stored in the own node.

If the comparison results are the same, it is determined that the node bypass has not been performed and is normal. If the comparison result is different, it is determined that the upstream adjacent node has been bypassed, and the fact that the bypass has occurred and the address of the upstream adjacent node stored in advance are notified to other nodes by a packet. . The fact that this packet is a bypass notification packet is identified by the information part of the packet, the packet type (PI), or the like.

As a concrete operation example, the address notification packet receiving operation of the node B (1-2) in FIG. 1 will be described. Both nodes A (1-1) and B (1-2)
An address notification packet having each own node address is transmitted. The address notification packet transmitted by the node A (1-1) is sent to the node B through the optical fiber (3-1), the optical accessor (4-1) and the optical fiber (3-2).
Reach (1-2). Further, the address notification packet transmitted by the node C (1-3) is an optical fiber (3-5),
The node B (1-2) is reached through the optical accessor (4-3), the optical fiber (5-1), the optical accessor (4-1), and the optical fiber (3-2).

The optical signal strength of the packet transmitted by the node C (1-3) passes through the two optical accessors (4-3, 4-1), and the optical fiber (5) is set to have a large loss.
-1), it is smaller than the optical signal intensity from the node A (1-1). Therefore, the node A (1-1),
If both C (1-3) are operating, node C (1-
The optical signal from 3) is masked by the optical signal from node A (1-1) and is not received by node B (1-2).

Therefore, normally, the node B (1-2) receives only the packet from the node A (1-1), and the node B (1-2) receives the packet from the node A (1-1). )
Receives the address notification packet from. Node B (1
-2) stores in advance the address of the node A (1-1) as the address of the adjacent node, and the node B (1-
In 2), when the address notification packet is received, it is the same as when the address on the packet is compared with the storage address. Therefore, node A is not bypassed and is judged to be normal.

When the optical signal from the node A (1-1) is stopped due to the failure of the node A (1-1), the disconnection of the optical fiber (3-1), etc., the node B (1-2) changes to the node C. (1
-3) The address notification packet from 3) will be received. Since the address contained in this packet is different from the stored address, the node B (1-2) can recognize that the node A (1-1) has been bypassed. The node B (1-2) notifies other nodes that the node A (1-1) has been bypassed. As a notification method, a packet as shown in FIG. 2 can be used for notification.

In the above-described embodiment, an example in which a packet is used for notifying an adjacent node of its own node address has been described. However, as shown in FIG. It is possible. FIG. 3 is an explanatory diagram showing an example of the structure of a frame. (7-1) is a frame header part, (7-2) is an information area in which information is transferred, and (7-3) is an address notification area. .

Generally, the frame length of the frame header section (7-1) and the information area (7-2) is fixed, and the information area (7-2) is divided into short fixed-length slots for use. When the address notification area (7-3) is present in the area of the frame header part (7-1), each node reads this area and receives the address of the upstream adjacent node and the address of its own node. Is written in this area.

In the network configuration of FIG. 1, since the node B (1-2) normally receives the optical signal from the node A (1-1), the node A (from the address notification area (7-3) The address 1-1) is received. Node A
When the optical signal from the node A (1-1) is stopped due to a failure of (1-1) or the like, the node B (1-2) changes to the node C (1
-3), the optical signal from the node C (1-3) is received from the address notification area (7-3) of the frame header section (7-1). Since this is different from the address of the adjacent node (A) stored in the node B (1-2), the node A (1-1)
Is judged to have been bypassed, and other nodes are notified accordingly.

FIG. 4 is an explanatory diagram showing a packet configuration example in the case where the address notification area (7-3) in FIG. 3 is provided in the header portion of the packet. In FIG. 4, (8
-1) is a header part of the packet, (8-2) is an information part of the packet, and (8-3) is an address notification area. Also in this case, as in the case of the frame configuration of FIG. 3, each node reads the address notification area (8-3), receives the address of the upstream adjacent node, writes the own node address in this area, and sends it. To do. This makes it possible to perform the same operation as in the case where the frame structure of FIG. 3 is adopted.

The embodiments of the present invention have been described above by giving some concrete examples of the method of notifying the addresses. In the above description,
Although each node has been described as storing the address of the upstream adjacent node in advance, the previously received address is always updated and stored as the address of the upstream adjacent node, and this and the received address are It is also possible to notify at different times.

In this case, even if the address of the upstream adjacent node is changed, it cannot be determined by the receiving node whether the cause is that the upstream adjacent node is bypassed or the bypassed node enters the ring again. . Therefore, the node that has detected the address change of the upstream adjacent node notifies other nodes of both the stored address and the received address. The node that has received this notification can determine that its own node has been bypassed if the stored address is the address of its own node. Further, when the connection state of all nodes is known in advance at the maintenance node or the like, a new connection state can be generated from this notification.

In the configuration of FIG. 1 described above, the optical accessor is installed at one location and the node and the optical fiber are bypassed. This method can deal with failures of both the node and the optical fiber, but since the wiring is a star type centering on the optical accessor, it has a feature that the fiber length becomes long. In this configuration, the optical accessor (4-
The present invention can be similarly applied even if 1) to (4-3) are created on one substrate.

Next, another embodiment will be described. FIG. 5 shows an embodiment in which only the node is bypassed. In FIG. 5, (1-1) to (1-3) are nodes A to C and (9-
1) to (9-3) are optical couplers, and (10-1) to (10-
3) is an optical branching device, (11-1) to (11-3), (12)
-1) to (12-3) are optical fibers.

The optical signal that has entered the optical branching device (10-1) is branched by the optical branching device and separated into the node A (1-1) and the optical coupler (9-1). In the optical coupler (9-1), the optical signal from the node A (1-1) and the optical signal from the optical branching device (10-1) are combined and output to the optical fiber (11-1). With such a configuration and by appropriately setting the attenuation amount of the optical fiber (12-1), the node B (1-2) normally operates as the node A (1-1) as in the embodiment of FIG. The optical signal of the node A (1-1) can be received, and the optical signal of the node C (1-3) can be received when the node A (1-1) fails.

Even with such a configuration, bypass detection can be performed by checking the address of the adjacent node on the upstream side according to the present invention, as described above. With this configuration,
Although the failure of the optical fibers (11-1) to (11-3) cannot be dealt with, there is a feature that the lengths of the optical fibers (11-1) to (11-3) become short.

The bypass structure using the optical accessor, the optical branching device, and the optical coupler has been described above. However, even if these parts are replaced with an electrical branching device and a coupler, and a metallic line is used, the present invention is similarly applied. Applicable. further,
The bypass function can be realized by configuring the branching device, the coupler, and the accessor with an optical switch and an electric switch, and switching the switch by detecting the stop of the optical signal and the electric signal. It is possible.

[0030]

As described above, in the present invention, in the ring network having the bypass function, the address of the adjacent node is constantly checked to detect the occurrence of the bypass due to the failure of the transmitting side of the node by the frame header or the packet. It is possible to notify the concerned node and other nodes of the failed node. For this reason,
The following effects can be expected.

The failure of the transmission unit of the node or the transmission path between the transmission unit of the node and the optical accessor is notified to all the nodes capable of receiving signals by notification from other nodes, and all the nodes quickly grasp the failure. can do.

For maintenance purposes, even when a node is blocked, the other node is notified by bypass, so that the reception interruption of the node is unlikely to be affected and the maintenance becomes easy.

In particular, the present invention exerts its effect in a building with many breakages in the transmission line cable or in an intelligent building with a large number of connection nodes, and has high network reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a ring network having a bypass function.

FIG. 2 is an explanatory diagram showing a configuration example of a packet used in the present invention.

FIG. 3 is an explanatory diagram showing a configuration example of a frame used in the present invention.

FIG. 4 is an explanatory diagram showing another configuration example of a packet used in the present invention.

FIG. 5 is a block diagram showing a ring network having a bypass function of only nodes.

FIG. 6 is a block diagram showing a conventional ring network without a bypass function.

[Explanation of symbols]

(1-1) to (1-5) ... node, (2-1) to (2-
5) ... Transmission path, (3-1) to (3-6) ... Optical fiber,
(4-1) to (4-3) ... Optical accessor, (9-1) to
(9-3) ... Optical coupler, (10-1) to (10-3) ...
Optical splitter, (11-1) to (11-3) ... Optical fiber,
(12-1) to (12-3) ... Optical fiber

Claims (1)

[Claims] 1. In a ring-type network in which a plurality of nodes are connected to each other by a transmission path so as to bypass each node to form a ring, each node has a storage unit for storing an address of an adjacent node and the storage unit. When a certain node is bypassed, the address of the bypassed node is associated with the downstream adjacent node when a certain node is bypassed. Since the address of another node does not arrive and is received and received, the adjacent node downstream uses the comparison means and the address of the adjacent node stored in the storage means and another node that has received the address. The node is characterized by knowing the existence of the bypassed node from the point where it is different by comparing with the address of the other node and notifying it to other nodes. Dobaipasu notification method.