JP2018157461A - Optical dual-loop transmission system and communication method for optical dual-loop transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain stability improvement of a network while limiting data transmission from startup of an additional node to confirmation by confirming an overlap node address without grasping node information of an adjacent node or adopting a polling system when adding a node to a constructed transmission line.SOLUTION: In an optical dual-loop transmission system, a loop master "#0" transmits a loop control frame to which connection areas of nodes "#0" and "#2" to "#6" are added. Each of the loop slaves "#2" to "#6" includes a node connection area update circuit for setting a node address of the node to the connection area. When starting up the loop slaves "#2" to "#6", transmission is set invalid and a CPU judges whether the node address of the node is overlapped with the node address of the other node from the connection area. If the node addresses are not overlapped, the transmission is made valid and if overlapped, on the other hand, the transmission is kept invalid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical double loop transmission system in which a plurality of nodes are communicably connected in a double link form by a transmission medium such as an optical fiber, and a communication method therefor.

  Usually, when a disconnection or a node down occurs at a certain location, the optical double loop transmission system performs a loopback process (turnback process) at the detected terminal node and holds the loop system.

  An outline of the loopback processing will be described with reference to FIG. In FIG. 4, “# 0” indicates a node of a loop master (line control station), and “# 2” to “# 6” indicate nodes of a loop slave (relay station). Here, a loopback process is shown when the node “# 5” goes down due to disconnection or power down.

  That is, the node “# 6” sends back the data frame of the 1-system reception 1R from the 2-system transmission 2T to the node “# 3” side through the 2-system optical fiber 10b, and the node “# 4” transmits the data of the 2-system reception 2R. The data frame is sent back from the 1-system transmission 1T to the loop master (node “# 0”) side through the 1-system optical fiber 10a.

  When node down occurs in the optical double loop transmission path (transmission path using the optical fibers 10a and 10b) as described above, termination processing by loopback is executed at nodes at both ends of the down node. However, when a new node is added to the transmission line instead of a down node, a situation may occur in which a plurality of nodes having overlapping node addresses coexist.

  For example, when node “# 5” in FIG. 4 is set to “# 3” and added to the transmission path, a plurality of nodes having overlapping addresses coexist, and a data frame is transmitted from each node. Therefore, data transmission / reception between the nodes cannot be performed normally, and there is a possibility that the system of the entire network may be down. Patent Documents 1 and 2 are known as techniques for solving this problem.

  In Patent Document 1, when there are a plurality of nodes having overlapping addresses in the optical double loop transmission system, the node that first receives the node confirmation frame from the loop master transmits a response frame, and a plurality of responses are transmitted on the transmission path. The frame is prevented from being transmitted.

  In Patent Document 2, a test target node transmits a node address collection frame to which a test node address is added, and collects the node address of each node on the transmission path. It is determined whether or not the node address of each node collected here overlaps with the node address held by itself.

JP 2000-92100 A Japanese Patent Application 4-84537

  According to Patent Document 1, when the power is turned on, a confirmation process of the adjacent station and the transmission path state is executed, and the node address of the adjacent node is acquired. Here, the other node that does not send the response frame compares the acquired node address with the address of the adjacent node given to the node confirmation frame. If the two addresses are different, the node is determined to be a duplicate node. A method that does not respond is adopted.

  However, adjacent nodes must grasp the node information of the adjacent nodes, and because of the polling method from the loop master, a node confirmation frame must be transmitted for each node, resulting in poor responsiveness. .

  According to Patent Document 2, although node address duplication is confirmed by transmitting a node address collection frame to which a test node address is added, data transmission is limited between the addition of the node to be tested and the confirmation. As a result, there is a possibility that data transmission from a plurality of nodes having overlapping node addresses may occur in the meantime.

  The present invention has been made to solve the above-mentioned problems of the prior art, and adopts a node information grasping and polling method when adding a node to an already constructed transmission line. It is an object of the present invention to check the overlapping node address without any problem, and to suppress the data transmission from a plurality of nodes having the overlapping node address between the node addition and the confirmation to contribute to the improvement of the stability of the network.

  The optical duplex transmission system of the present invention includes a loop master that transmits a loop control frame to which a connection area for setting the node address of each node is added, and the node address of the own node in response to reception of the loop control frame. A loop slave that bypasses the loop control frame and confirms the node address of the node connected on the transmission line from the connection area of the loop control frame, and the node address of the own node and other nodes Node duplication checking means for judging whether or not the node address overlaps, and before the node duplication checking means, the loop slave is set to receive valid and transmission invalid, and the node duplication checking means does not duplicate If it is determined that the transmission is valid, the transmission is valid. It is characterized by being a.

  The communication method of the optical duplex transmission system of the present invention includes a loop control frame transmission step in which a loop master of a node group transmits a loop control frame to which a connection area for setting a node address of each node is added; Each loop slave sets the node address of its own node in the connection area in response to the reception of the loop control frame and bypasses the loop control frame. The loop slave transmits from the connection area of the loop control frame. A node duplication confirmation step for confirming a node address of a node connected on the road and judging whether or not the node address of the own node and the node address of another node overlap. Before the loop slave, reception is enabled and transmission is disabled. If it is determined that no duplicate node duplication check step, while the transmission of the loop slave is valid, if overlapping and determined, is characterized in that the transmission of the loop slave is to remain disabled.

  According to both the above inventions, the node added to the already established optical double loop transmission line without grasping the node information of the adjacent node or adopting the polling method is the connection area of the loop control frame and the own node address. To check the duplicate node address.

  At this time, before the node address duplication is confirmed, the transmission of the loop slave is set to be invalid, and if it is judged as duplication, the transmission is continuously invalidated. Therefore, the additional node cannot transmit data from the time when the node is added until the confirmation, and data transmission is suppressed from a plurality of nodes having duplicate node addresses during that time.

  In addition, if the loop master transmits a loop control frame at a fixed period, it is possible to respond to node addition at any time, and if the loop control frame transmitted from the loop master goes around each loop slave on the transmission path, all nodes Node address is set in the connection area.

  According to the present invention, when adding a node to an already constructed transmission line, it is possible to confirm a duplicate node address without grasping node information of an adjacent node or adopting a polling method. Further, data transmission from a plurality of nodes having duplicate node addresses during the period from the node addition to the confirmation is suppressed, and this point can contribute to an improvement in network stability.

1 is a system configuration diagram of an optical duplex transmission system according to an embodiment of the present invention. The block diagram of the controller of the same each node. The operation | movement figure when adding a node to the transmission line of the optical duplex transmission system. The operation | movement figure of a loopback process.

  Hereinafter, an optical duplex transmission system according to an embodiment of the present invention will be described. In this optical duplex transmission system, when a new node is added to an already established optical duplex transmission line, the node address on the already established optical duplex loop transmission line is confirmed, and the same node address exists. In this case, a technique is provided in which a new node is not connected to the optical double loop transmission line.

≪Configuration example≫
A configuration example of the optical duplex transmission system will be described with reference to FIG. Here, the optical duplex transmission system 1 is constituted by a transmission system using two channels of optical modules 30, and a plurality of nodes “# 0”, “# 2” to “# 6” are looped by optical fibers 10a and 10b. Are connected twice.

  In the optical duplex transmission system 1, the 1-system reception 1R and the 1-system transmission 1T optical modules 30 are separated, and the 2-system reception 2R and the 2-system transmission 2T optical modules 30 are also separated. As a result, in the normal operation, the data direction of the 1 system 1R, 1T (right system loop) and the data direction of the 2 system 2R, 2T (left system loop) are reversed.

  At this time, normally, the 1 system 1R, 1T is used as an operation system, and the 2 system 2R, 2T is used as a standby system. In FIG. 1, node “# 0” indicates a loop master (line control station), and nodes “# 2” to “# 6” indicate loop slaves (relay stations).

  The controllers of the optical modules 30 of the nodes “# 0”, “# 2” to “# 6” will be described with reference to FIG. The controller 40 is configured by a computer, and includes a CPU 51, a memory 52, a self-node detection circuit 61, a data bypass FIFO 62, a communication LSI 63, a loop control frame transmission unit 64, a loop control frame detection circuit 65, and a loop configuration detection RAM 66. , A node connection area update circuit 67, a node duplication check RAM 68, and buffers 69 and 70. Here, the CPU 51, the memory 52, the communication LSI 63, and the RAMs 66, 68 are connected via the bus 53.

  The own node detection circuit 61 detects whether or not the node receiving the data frame is a data frame transmitted by the own node, and if the data frame is transmitted by the own node, the data bypass FIFO 62 is bypassed without performing the bypass operation. 69 is off-gate controlled.

  The data bypass FIFO 62 is a FIFO for bypassing data frames that flow on the optical double loop transmission path (transmission path using the optical fibers 10a and 10b), and bypasses data frames other than its own node to nodes downstream of the transmission path. The control to be executed is executed. On the other hand, for the data frame of the own node, the buffer 69 is off-gate controlled by the own node detection circuit 61 as described above, and bypass control of the data bypass FIFO 62 is not executed.

  The communication LSI 63 is a means for executing transmission / reception of a data frame, and corresponds to a MAC controller when “ETHERNET (registered trademark)” is adopted. Here, the CPU 51 stores the data frame for transmission in the memory 52, and then outputs the data frame stored in the memory 52 via the communication LSI 63. The received data frame is stored in the memory 52 via the communication LSI 63, and the CPU 51 recognizes the data frame received in the memory 52.

  The loop control frame transmission unit 64 transmits a loop control frame for controlling the transmission path. That is, the loop master “# 0” transmits a loop control frame through the transmission unit 64 at a constant cycle while not transmitting a data frame (loop control frame transmission step).

  A node connection area in which the node number (node address) of each node is composed of bit data is added to this loop control frame. This node connection area consists of a data amount corresponding to the number of stations connected to the transmission path (for example, 128 bits if the maximum number of stations is 128), and checks the node number of a node that already exists in the transmission path. Used for. Note that the transmission cycle of the loop control frame is set in advance to the loop master “# 0” according to the specifications and settings. For example, the loop control frame may be set to be transmitted before the communication LSI 63 transmits the data frame.

  The loop control frame detection circuit 65 receives and detects a loop control frame flowing on the transmission path, and outputs the detected loop control frame to the node connection area update circuit 67. Further, a connection area is extracted from the detected loop control frame, and the extracted connection area is output to the RAM 68 for storage.

  The node connection area update circuit 67 receives the loop control frame as input, sets the bit data of the node number of its own node in the node connection area of the loop control frame (loop control frame processing step), and sets the loop control frame as a downstream node. Is bypassed via the buffer 70.

  Thus, if the loop control frame transmitted from the loop master “# 0” is bypassed in the order of the loop slaves “# 2” to “# 6”, the node connection area includes each of the transmission lines connected to the transmission path. Bit data of the node numbers of the nodes “# 0”, “# 2” to “# 6” are sequentially set.

≪Operation example when adding a node≫
An operation example when an optical duplex transmission system node is added will be described with reference to FIG. This operation example shows an example in which a loop slave “# 5” in FIG. 1 is set to “# 3” and a node is added to the transmission path that has already been constructed. Here, all the bit data (node numbers) of the nodes “# 0”, “# 2” to “# 6” already connected to the transmission path are set in the node connection area of the loop control frame. Shall.

  First, when adding a loop slave to the already constructed transmission line, a newly added loop slave (in FIG. 3, “# 3” surrounded by a broken line between (1) and (1): The additional node “# 3” is activated in a state of data reception “ENABLE (valid)” and data transmission “DISABLE (invalid)”.

  Therefore, the additional node “# 3” receives and detects the loop control frame output from the loop master “# 0” in the detection circuit 65 within a certain period after the power is turned on. A node connection area is extracted from the loop control frame, and the extracted node connection area is output to the RAM 68 and stored therein.

  At this time, the CPU 51 of the additional node “# 3” reads the node connection area with reference to the RAM 68 and confirms whether or not the same node number as the own node, that is, the same node address exists in the node connection area (node). Duplicate check step). As a result, it is confirmed whether or not there is another node having the same node address as that of the additional node “# 3” on the transmission path.

  As a result of the confirmation, if the same node address as the own node does not exist, the data transmission of the additional node “# 3” is switched to “ENABLE (valid)”, and the additional node “# 3” is connected to the transmission path. . On the other hand, if the same node address as that of the own node exists as a result of the confirmation, the data transmission of the additional node “# 3” is maintained in the “DISABLE (invalid)” state. Here, since there is another “# 3” loop slave (shown) on the transmission path, the additional node “# 3” keeps data transmission “DISABLE (invalid)”.

  Therefore, when the node “# 6” transmits the data frame from the 1-system transmission 1T to the additional node “# 3”, the additional node “# 3” can be received by the 1-system reception 1R, but the 1-system 1T to the node “# 3”. Cannot send to # 4 ". Similarly, when the node “# 4” transmits the data frame from the second-system transmission 2T to the additional node “# 3”, the additional node “# 3” can be received by the second-system reception 2R, but the second-system transmission 2T to the node It cannot be sent to “# 6”.

  In this case, the presence of the additional node “# 3” is ignored, and normal loopback processing is executed. That is, the node “# 6” sends the data frame of the 1-system reception 1R back from the 2-system transmission 2T to the node “# 3” through the 2-system optical fiber 10b, and the node “# 4” transmits the data of the 2-system reception 2R. The frame is sent back from the 1-system transmission 1T to the loop master (node “# 0”) side through the 1-system optical fiber 10a.

  In this way, the additional node “# 3” is not connected to the transmission path, and only the other loop slave “# 3” can transmit the data frame, and the data frame by the plurality of nodes having the same node address (duplicate node address) can be transmitted. Sending is prevented. At this time, according to the optical duplex transmission system 1, the node number is set in the connection area by bypassing the loop control frame in the order of the loop slaves “# 2” to “# 6”, and the duplicate node address is confirmed. The CPU 51 only needs to compare the node connection area and the own node address, and it is not necessary to grasp the polling method or the node information of the adjacent node. In this sense, the problem of compression of node storage capacity and responsiveness has been improved.

  In particular, since the additional node “# 3” maintains the state of data transmission “DISABLE (invalid)” from the time of startup when the power is turned on, the additional node “# 3” transmits data from the time of startup until the confirmation of the duplicate address. In the meantime, only the other loop slave “# 3” can transmit the data frame.

  Therefore, according to the optical duplex transmission system 1, transmission of data frames by a plurality of nodes having duplicate node addresses is prevented not only after the confirmation of duplicate addresses but also during that time. Thereby, even after a new node is added to the transmission path, data transmission / reception between the nodes can be performed normally, and the stability of the entire network can be improved. Further, since the loop master “# 0” transmits the loop control frame at a fixed period, it is possible to cope with the addition of a node as needed.

  In addition, this invention is not limited to the said embodiment, It can apply and deform | transform and implement within the range described in each claim. For example, the configuration of the controller 40 is not limited to the figure, and the RAM 66 may also be used as the RAM 68. Further, the present invention can be configured as a communication method for the optical duplex transmission system 1 as well as the optical duplex transmission system. In this case, the above steps are executed by the optical duplex transmission system 1.

DESCRIPTION OF SYMBOLS 1 ... Optical duplex transmission system "# 0", "# 2"-"# 6" ... Node 10a, 10b ... Optical fiber 30 ... Optical module 40 ... Controller 51 ... CPU
52 ... Memory 53 ... Bus 61 ... Self-node detection circuit 62 ... Data bypass FIFO
63 ... Communication LSI
64 ... Loop control frame transmission unit 65 ... Loop control frame detection circuit 66 ... Loop configuration detection RAM
67 ... Node connection area update circuit 68 ... Node duplication check RAM
69, 70 ... buffer

Claims (6)

An optical duplex transmission system in which a plurality of nodes are connected in a double loop through a transmission line,
A loop master that transmits a loop control frame with a connection area for setting the node address of each node;
A plurality of loop slaves that sequentially bypass the loop control frame by setting the node address of the own node in the connection area in response to reception of the loop control frame,
The loop slave confirms the node address of the node connected on the transmission line from the connection area of the loop control frame, and determines whether or not the node address of the own node and the node address of the other node overlap. With
Before the node duplication check means is judged, the loop slave is set to receive invalid and transmit invalid.
An optical duplex transmission system characterized in that transmission is validated when it is determined that there is no duplication in the node duplication confirmation means, while transmission is invalidated when it is judged as duplication.   2. The optical duplex transmission system according to claim 1, wherein the loop master transmits a loop control frame at a constant cycle. The loop control frame transmitted from the loop master goes around each loop slave on the transmission path,
3. The optical duplex transmission system according to claim 1, wherein each loop slave sets a node address of its own node in a connection area in order. A communication method of an optical dual transmission system in which nodes are connected in a double loop through a transmission line,
A loop control frame transmission step in which a loop master of a node group transmits a loop control frame to which a connection area for setting a node address of each node is added;
A loop control frame processing step in which each loop slave of the node group sequentially sets the node address of its own node in the connection area and bypasses the loop control frame in response to reception of the loop control frame;
Node duplication confirmation step in which the loop slave confirms the node address of the node connected on the transmission line from the connection area of the loop control frame, and determines whether the node address of the own node and the node address of the other node overlap. And having
Before determining the node duplication check step, the loop slave is set to receive disabled and transmit disabled,
If it is determined that there is no duplication in the node duplication confirmation step, the transmission of the loop slave is validated,
The communication method of the optical duplex transmission system, wherein if it is determined that there is duplication, the transmission of the loop slave is continuously invalidated.   5. The communication method of an optical duplex transmission system according to claim 4, wherein, in the loop control frame transmission step, the loop master transmits the loop control frame at a constant cycle. In the loop control frame transmission step, the loop control frame transmitted from the loop master goes around each loop slave on the transmission path,
6. The optical duplex transmission system communication method according to claim 4 or 5, wherein in the loop control frame processing step, each loop slave sequentially sets the node address of its own node in the connection area.

Images