JP3886666B2 - Network system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a network system capable of realizing a mixed connection of a bus network and a loop network.
[0002]
[Prior art]
In recent years, digitalization of video and audio data has progressed, and the era in which networks that transmit computer data such as control commands and digital AV data typified by MPEG are used in applications such as ordinary homes and automobiles has been approached. Various and flexible network connection forms are required, such as easy expansion and reliability ranking by device group or data. Conventionally, when interconnecting networks of different topologies such as a bus type network and a loop type network, for example, literature (Naoe Kamae, July 6, 1992 edition, “Local Area Network”, Shogodo, 88)), it is common to use gateways or routers at the network layer. An example of the apparatus in this case is shown in FIG. In FIG. 10, 101 is a bus type network, 101a is a node connected to the bus type network 101, 102 is a gateway or router, 103 is a loop type network, 103a is a node connected to the loop type network 103, The bus network 101 and the loop network 103 are interconnected via a gateway or router 102.
[0003]
[Problems to be solved by the invention]
In general, a loop network has few optical fibers and optical modules that connect nodes, which is advantageous in terms of cost and excellent expandability of the node. However, the entire network operates only with some optical fiber breaks or node failures. Since it becomes impossible, there is a problem in reliability, and it is difficult to diagnose a faulty part, and there is also a problem in maintainability. On the other hand, bus-type networks are disadvantageous in terms of cost due to the increase in optical fibers and optical modules, but even if some optical fiber cuts or node failures occur, the failure of the failed nodes only affects the entire network. Since it is not given, it is highly reliable, and it is easy to diagnose a faulty part, so it is excellent in maintainability. Therefore, if you use a loop network and a bus network in a mixed connection that combines both networks according to the application and the importance of the equipment, the disadvantages of both are complemented and cost, reliability, expandability, and maintainability are excellent. Network construction is possible. However, devices such as gateways and routers have been used for mixed network connections, but these devices need to perform packet conversion at high speeds, so computer systems and complex devices are required. It was unsuitable for use in terms of cost or scale.
[0004]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a network system capable of realizing a mixed connection of a bus network and a loop network without using a gateway or a router.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, the invention according to claim 1 of the present application includes at least one loop composed of a plurality of nodes connected in a loop shape, and a plurality of nodes connected in a single node or loop shape. One or more loops composed of nodes have one or more input units and one or more output units, and a signal input from one input unit is branched without being processed, and all the output units A network system configured to be directly connected to a common transmission path output from the node, and a signal output from any one of the nodes is transmitted to all nodes, and in each loop, the own node among the nodes Is extinguished at either the most downstream node, which is a node directly connected to the common transmission path, or the node that outputs the signal.
[0006]
The invention according to claim 2 of the present application includes at least one loop composed of a plurality of nodes connected in a loop shape, and a single node or a plurality of nodes connected in a loop shape. One or more loops have one or more input units and one or more output units, and a signal that is input from one input unit is branched without being processed and is transmitted from all the output units. A network system configured to be directly connected to a route, wherein the node that sent the signal extinguishes the signal returned to the own node, and the output side of the own node among the nodes of each loop is the common When the most downstream node, which is a node directly connected to the transmission path, belongs to the same loop as its own node, the node that sent the signal passes the signal and sends the signal If the node belongs to a different loop and the own node is intended to eliminate the signal.
[0007]
The invention according to claim 3 of the present application includes at least one loop composed of a plurality of nodes connected in a loop shape, and a single node or a plurality of nodes connected in a loop shape. One or more loops have one or more input units and one or more output units, and a signal that is input from one input unit is branched without being processed and is transmitted from all the output units. Each node that is directly connected to the path and constitutes the loop has a node ID for recognizing its own node, and one node belonging to any of the plurality of loops becomes a token master node, and the token master node A node other than the node becomes a slave node, and a node in which the output side of the own node is directly connected to the common transmission path is the most downstream node. A network system, wherein the token master node is a transmission node ID that is a node ID of a node that is permitted to transmit a data packet, and a reception node ID that is a node ID of a node that should receive the transmitted data packet A token transmission device that transmits a token packet including the token packet, a token analysis device that analyzes the token packet, node setting information indicating whether the node is the most downstream node, a node ID of the token master node, and reception A storage device that temporarily stores information on the packet, a data transmission device that performs data packet transmission, and a switch that discards or passes the received token packet. The token analyzer that performs the analysis and the own node The node setting information as to whether or not it is the most downstream node, the node ID of the token master node and the storage device that temporarily stores the received packet information, the data transmission device that performs data packet transmission, and the received A switch for discarding or passing a token packet, and the token analysis device of each node is configured to discard the received token packet when the own node is a token master node when transmitting the token packet. The switch is controlled, the own node is the most downstream node as judged from the node setting information, and the own node is different from the token master node as judged from the node ID of the token master node and the node ID of the own node If it belongs to a loop, the received token packet is discarded. In other cases, the switch is controlled to pass the received token packet, so that the token packet is transmitted to all the nodes and the token packet disappears from the network. In addition, when the data packet is transmitted, the switch is controlled so that the received data packet is discarded when the local node is a transmitting node as judged from the received token packet information. Judgment: If the own node is the most downstream node, and the own node belongs to a different loop from the sending node, judging from the received token packet information and the node ID of the own node, the received data packet is discarded. Control the switch to make it happen, otherwise received Tapaketto By performing the control of the switch so as to pass, the data packet data packet is transmitted to all nodes in which to be destroyed from the network.
[0008]
The invention according to claim 4 of the present application is the network system according to claim 3, wherein the node IDs have the same value between nodes belonging to the same loop, and are different values between nodes belonging to different loops. The most downstream node determines whether the packet transmission node belongs to its own loop based on the loop address.
[0009]
The invention according to claim 5 of the present application is the network system according to any one of claims 1 to 4, wherein the common transmission path is an optical star coupler.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
(Embodiment 1)
FIG. 1 is a diagram showing a configuration example of a network system according to Embodiment 1 of the present invention. In FIG. 1, reference numerals 100, 110, 111, 112, 120, 121 denote nodes connected to the network, and 15 denotes an optical star coupler. The node 100 is a token master node, and the nodes 110, 111, 112, 120, and 121 are slave nodes. In addition, the node 100 is a loop master of loop 0 composed of the node 100, the node 110 is a loop master of loop 1 composed of the nodes 110, 111, and 112, and the node 120 is the nodes 120 and 121. It is a loop master of loop 2 composed of In FIG. 1, the direction of the arrow indicates the direction of data flow. As shown in FIG. 1, in the network according to the first embodiment, a loop in which a plurality of nodes are connected in one direction (loop 1 and loop 2) or a loop composed of a single node (loop 0) is The node connected to the optical star coupler 15 is used, and among the nodes constituting each loop, the node whose output side is directly connected to the optical star coupler 15 is a loop master.
[0011]
FIG. 2 is a diagram showing a configuration of a packet transmitted over the network in the network system according to the first embodiment. In FIG. 2, 21 is a token packet, 22 is a DS packet, and 23 is a data packet.
As shown in FIG. 2, the token packet 21 includes a transmission node ID (a node ID of a node that the token master node permits data transmission) and a reception node ID (a node ID of the node that the token master node permits data reception). Including. Here, the node ID includes a loop address to which the node belongs and a node address on the loop. The loop address is a number unique to each loop, and the node address is a node number unique to each node on the loop. In order to specify a specific node on the network, a loop address to which the node belongs and a node address of the node on the loop may be specified. The node ID description method in this embodiment is (loop address.node address). For example, the node ID of a node having a loop address of 1 and a node address of 2 is expressed as (1.2).
[0012]
As shown in FIG. 2, the DS packet 22 includes a Destination Status field. The DS packet 22 is transmitted to the node designated by the receiving node in the receiving node ID field of the token packet 21, and the DS packet 22 includes information indicating whether or not the receiving node is in a data receivable state. .
As shown in FIG. 2, the data packet 23 includes a field of data to be actually transmitted. The data packet 23 is transmitted to the node designated by the transmission node in the transmission node ID field of the token packet 21.
[0013]
FIG. 3 is a diagram showing a state of a packet transmitted on the network. In FIG. 3, 31 is a token packet, 32 is a DS packet, and 33 is a data packet. In the network system according to the present embodiment, as shown in FIG. 3, the token packet, the DS packet, and the data packet are transmitted in this order on the network, and thereafter this is repeated at regular intervals.
[0014]
FIG. 4 is a diagram showing a detailed configuration of the network system according to the first embodiment of the present invention. In FIG. 4, reference numerals 100, 110, 111, 112, 120, 121 denote nodes connected to the network, and 15 denotes an optical star coupler. The node 100 is a token master node, and the nodes 110, 111, 112, 120, and 121 are slave nodes. Node 100 belongs to loop 0, nodes 110, 111, and 112 belong to loop 1, and nodes 120 and 121 belong to loop 2. Nodes 100, 110, and 120 are loop masters. The node ID of the node 100 is (0.0), the node ID of the node 110 is (1.0), the node ID of the node 111 is (1.1), the node ID of the node 112 is (1.2), The node ID of the node 120 is (2.0), and the node ID of the node 121 is (2.1). Thus, each node has a unique node ID.
[0015]
As shown in FIG. 4, the slave nodes 111, 112, 121 and the loop masters 110, 120 that are not token master nodes include a token analysis device that analyzes tokens and packets, a nonvolatile memory that stores initial settings, and token analysis. The apparatus includes a storage device connected to the device and the nonvolatile memory, a data transmission device that transmits data, and a switch that disconnects or connects the loop. When the switch is switched to the A side, the loop is connected, and when the switch is switched to the B side, the loop is disconnected. As illustrated in FIG. 4, the token master node 100 includes a token transmission device that transmits a token in addition to the components of the slave node. When the switch is switched to the A side, the loop is connected, and when the switch is switched to the B side, the loop is disconnected.
In the above configuration, the nonvolatile memory may be anything as long as it stores the initial settings and can set the initial settings in the storage device, and may be realized by, for example, a dip switch.
[0016]
Next, the operation of the network system according to the first embodiment configured as described above will be described.
The operation will be described by taking as an example a case where the token master node 100 transmits a token packet having a transmission node ID (2.1) and a reception node ID (1.1).
In the network system according to the first embodiment of the present invention, the node that transmitted the packet (all packets including the token packet) switches the switch so as to discard the packet returned to the own node. The loop master switches the switch, discards the packet transmitted by the node belonging to the other loop, passes the packet transmitted by the node belonging to the own loop, and transmits and discards the packet.
[0017]
First, an outline of the operation sequence will be described. The operation sequence includes an initialization sequence and a normal operation sequence.
The initialization sequence is activated when power is turned on or reset, and performs an initialization process. In the initialization sequence, the token master node is set to operate as the token master node and the loop master is set to operate as the loop master by reading the information set in advance in the nonvolatile memory or the DIP switch into the storage device. Knows the loop address ("0" in this example) of the loop to which the token master node belongs, and all nodes including the token master node know the node ID (loop address and node address) of the own node.
[0018]
FIG. 9 is a diagram illustrating an example of information set in advance on the nonvolatile memory. In this example, it is assumed that the address of each flag, address, and ID on the nonvolatile memory is known in advance. As shown in FIG. 9, if information is set on the non-volatile memory, for example, information stored in the address of the token master node flag on the non-volatile memory is read. If it is “1”, it can be set as a token master. The same applies to the loop master flag, the loop address of the token master node, and the own node ID.
[0019]
The normal operation sequence is an operation sequence in which a node actually transmits and receives a packet. The normal operation sequence includes a token mode for transmitting a token packet, a DS mode for transmitting a DS packet, and a data mode for transmitting a data packet. Consists of modes. Hereinafter, the operation in each mode of the normal operation sequence will be described in detail.
[0020]
First, the token mode will be described with reference to FIG. FIG. 4 is a diagram showing the switch state of each node when the token packet is transmitted and the flow of the token packet. In the figure, the thick line shows the flow of the token packet.
The token master node 100 assembles a token packet with the token transmission device, processes the packet into a form transmitted on the network with the data transmission device, and the token analysis device switches the switch to the B side and transmits the token packet. Here, it is assumed that the transmission node ID specified by the token packet is (2.1) and the reception node ID is (1.1).
[0021]
The token analysis devices of the loop masters 110 and 120 compare the loop address “0” of the token master node 100 stored in the initialization sequence with the addresses of the own loop (110 is “1”, 120 is “2”), and the comparison is made. Since the results are different, it is determined that the packet is from another loop, and the switch is switched to the B side.
The token analysis devices of the slave nodes 111, 112, and 121 switch the switch to the A side so as to pass the packet in the token mode.
[0022]
The token packet transmitted from the token master node 100 is transmitted to the nodes 100, 112, and 121 via the optical star coupler 15. In the loop 0 of the loop address 0, the token packet transmitted from the optical star coupler 15 is discarded by the token analysis device of the token master node 100. In the loop 1 of the loop address 1, the token packet is transmitted in the order of the slave node 112, the slave node 111, and the loop master 110, and the token packet is discarded by the token analysis device of the loop master 110. Similarly, in the loop 2 of the loop address 2, the token packet is transmitted in the order of the slave node 121 and the loop master 120, and the token packet is discarded by the token analysis device of the loop master 120.
The token analysis devices of all the nodes including the token master node store the transmission node ID and the reception node ID in the received token packet in the storage device.
[0023]
As described above, the token packet is transmitted from the token master node 100 to all the nodes, received, and discarded by the loop master and the token master node. The above is the operation in the token mode.
[0024]
Next, the DS mode will be described with reference to FIG. FIG. 5 is a diagram showing the switch state of each node when the DS packet is transmitted, and the flow of the DS packet. In the figure, the bold line shows the flow of the DS packet.
When the token analysis device of all nodes including the token master node and the loop master compares the reception node ID stored in the storage device by the operation in the token mode described above with the own node ID (in this case, only the node 111) If the node is in a state where data can be received, a DS packet indicating “data reception is possible” is assembled. If the node is in a state where data cannot be received, DS indicating “data reception is not possible” The packet is assembled, processed into a form that is transmitted on the network by the data transmission device, and the DS packet is transmitted by switching the switch to the B side.
[0025]
The token analysis device of the loop master 110 determines that the own node does not issue a DS packet because the received node ID stored in the storage device does not match the own node ID, and then receives the received node ID stored in the storage device. The loop address “1” is compared with the address “1” of the own loop. Since they match, it is determined that the DS packet is transmitted from the node in the own loop, and the switch is switched to the A side.
[0026]
The token analysis devices of the loop masters 100 and 120 determine that the own node does not issue a DS packet because the received node ID stored in the storage device does not match the own node ID, and then receives the received node stored in the storage device. The loop address “1” of the ID is compared with the address of the own loop (node 100 is “0” and node 120 is “2”). Switch to the side.
The token analysis devices of the slave nodes 112 and 121 switch the switch to the A side so that the packet is allowed to pass because the reception node ID stored in the storage device does not match the own node ID.
[0027]
The DS packet transmitted from the node 111 passes through the node 110 and is transmitted to the nodes 100, 112 and 121 via the optical star coupler 15. In the loop 0, the DS packet transmitted from the optical star coupler 15 is discarded by the token master node 100. In the loop 1, the DS packet is transmitted in the order of the slave node 112 and the slave node 111, and the DS packet is discarded at the node 111 that transmitted the DS packet. In the loop 2, the DS packet is transmitted in the order of the slave node 121 and the loop master 120, and the DS packet is discarded by the loop master 120.
[0028]
When the token analysis devices of all the nodes including the token master node match and match the transmission node ID stored in the storage device by the operation in the token mode described above and the own node ID (here, only the node 121 matches). The received DS packet is received, and the contents are stored in the storage device.
[0029]
As described above, the DS packet is transmitted from the node 111 designated as the receiving node by the token packet to all the nodes, received by the node 121 designated as the sending node by the token packet, and received by the loop masters 100 and 120 and the DS packet. Is discarded by the node 111 that transmitted The above is the operation in the DS mode.
[0030]
Finally, the data mode will be described with reference to FIG. FIG. 6 is a diagram showing the switch state of each node when the data packet is transmitted and the flow of the data packet. In the figure, the thick line indicates the flow of the data packet.
When the token analysis device of all nodes including the token master node and the loop master matches the transmission node ID stored in the storage device by the operation in the token mode described above and the own node ID is matched (here, only the node 121) If the content of the DS packet stored in the storage device in the DS mode indicates “data can be received”, the data packet is assembled, processed into a form transmitted on the network by the data transmission device, and token analysis is performed. The device switches the switch to the B side and transmits a data packet. Even if the token analysis device of all nodes including the token master node and the loop master matches the result of comparison between the transmission node ID stored in the storage device and its own node ID, the contents of the DS packet stored in the storage device in the DS mode are the same. If “data cannot be received” is indicated, data packet transmission is postponed.
[0031]
Since the token analysis device of the loop master 120 does not match the transmission node ID stored in the storage device with the own node ID, the token analysis device determines that the own node does not issue a data packet, and then the transmission node ID stored in the storage device. The loop address “2” is compared with the address “2” of the own loop. Since they match, it is determined that the data packet is transmitted from the node in the own loop, and the switch is switched to the A side.
[0032]
Since the transmission node ID stored in the storage device and the own node ID do not match, the token analysis devices of the loop masters 100 and 110 determine that the own node does not issue a data packet, and then the transmission node stored in the storage device The loop address “2” of the ID is compared with the address of the own loop (100 is “0”, 110 is “1”), and since they are different, it is determined that the data packet is transmitted from the node in the other loop, and And switch the switch.
The token analysis devices of the slave nodes 112 and 111 switch the switch to the A side so that the packet is allowed to pass because the transmission node ID stored in the storage device does not match the own node ID.
[0033]
The data packet transmitted from the node 121 passes through the node 120 and is transmitted to the nodes 100, 112, and 121 via the optical star coupler 15. In the loop 0, the data packet transmitted from the optical star coupler 15 is discarded by the token analysis device of the token master node 100. In the loop 1, the data packet is transmitted in the order of the slave node 112, the slave node 111, and the loop master 110, and the data packet is discarded by the token analysis device of the loop master 110. In the loop 2, the data packet transmitted from the optical star coupler 15 is discarded by the slave node 121 that has transmitted the data packet.
The token analysis devices of all the nodes including the token master node receive the transmitted data packet when the received node ID stored in the storage device matches the own node ID and match.
[0034]
As described above, the data packet is transmitted from the node 121 designated as the transmission node by the token packet to all the nodes, and received by the node 111 designated as the reception node by the token packet. It is discarded at the node 121 that sent the packet. The above is the operation in the data mode.
When a certain time has elapsed since the token master node transmitted the previous token packet, the token master node returns to the token mode again, and thereafter, the token mode, DS mode, and data mode operations are repeated to realize data transmission.
[0035]
As described above, the node that sent the packet (token packet, DS packet, data packet) switches the switch so that the packet returned to itself is discarded, and the loop master sends it from the node that belongs to the other loop. By switching the switch so that the discarded packet is discarded, the packet is transmitted and discarded.
[0036]
As described above, in the network system according to the first embodiment, a simple physical or electrical switch for directly interconnecting nodes at the data link (media access control: MAC) layer is provided, and a node other than the transmitting node receives the node. The packet processing is performed by transmitting or extinguishing the packet by switching the switch by judging from the loop address of the loop to which the transmitting node belongs whether to transmit the packet as it is to the upper node or to discard it at its own node. A loop and bus mixed network system in which a single node or a group of nodes connected in a loop is connected to one optical star coupler can be constructed.
[0037]
In the network system according to the first embodiment, a means for switching whether a packet received by each node is directly transmitted to an upper node or discarded by the own node is short-circuited or disconnected between the input terminal and the output terminal of the node. Although it is realized by a physical switch, the switching means can be configured as long as it can switch whether the received packet is directly transmitted to the upper node or discarded by the own node. Also good.
[0038]
The configuration of the network system of the present invention is not limited to that shown in the first embodiment, and the number of loops, the number of nodes in the loop, and the number of nodes directly connected to the optical star coupler are as follows. It is possible to arbitrarily set the bit width of the node ID and various physical limitations. In the first embodiment, the token master node is directly connected to the optical star coupler. However, the token master node can be arranged at an arbitrary position in the loop.
[0039]
In the network system according to the first embodiment, the token packet, the DS packet, and the data packet are transmitted in this order. If the receiving node cannot receive the data, the data is temporarily discarded on the transmission path, In a network system in which retransmission is requested by requesting the transmission of the data again, or in a network system in which retransmission is permitted by requesting the lost data group after the data is overwritten by the receiving node. The DS packet transmission phase may be omitted.
[0040]
In the network system according to the first embodiment described above, there is only one node (node 100) on the network system that is provided with the token transmission device and can be a token master node. There may be a plurality of nodes on the network system that can be token master nodes. Even in such a case, the node set to operate as the token master node based on information set in advance in the nonvolatile memory or the DIP switch must be unique on the network.
[0041]
In addition, as shown in FIG. 7, a bus device composed of an optical star coupler and a signal output device is used instead of reading the initial setting previously set in the DIP switch or the nonvolatile memory in the initialization sequence into the storage device. 75 includes a signal output device 75a and a signal line 74 for outputting a signal to a node 72 connected to the optical star coupler. Nodes 71 and 72 on the loop network connected to the bus device by the optical star coupler are connected to the signal line 74. Nodes connected to the optical star coupler by transmitting a signal indicating that the signal output device 75a is directly connected to the optical star coupler. Only the signal detector 72a of 72 detects the signal and operates as a loop master in the storage device of the node 72. By setting to, it may be configured such that the node 72 that is directly connected to the optical star coupler is recognized as the automatic loop master.
[0042]
Further, instead of reading the initial setting previously set in the DIP switch or the non-volatile memory in the initialization sequence into the storage device, the setting device 82 is connected to the node 81 as shown in FIG. To the storage device 81a. At this time, the setting device 82 may be configured by a computer or the like, and the node 81 and the setting device 82 may be connected by serial communication.
[0043]
In addition, according to the present invention, a unique loop address is provided for a loop to which a node belongs, and a method for transmitting or discarding data by a loop master is not only a network system using a token as described in the above embodiment, The present invention is also applicable to a network system using a CSMA (Carrier Sense Multiple Access) method, a TDMA (Time-Division Multiple Access) method, or an arbitration method using a bus arbiter. When applied to a network system using the CSMA method, the TDMA method, or the arbitration method by the bus arbiter, a loop address unique to the loop to which the node belongs is provided, the source loop address is added to the transmission data, and the information is stored. A bus and loop mixed connection using an optical star coupler, as in the above embodiment, by the loop master analyzing and transmitting or discarding data, and the source node discarding the data returned to its own node Is easily realizable.
[0044]
【The invention's effect】
As described above, according to the present invention (claim 1), at least one loop composed of a plurality of nodes connected in a loop shape, and a plurality of nodes connected in a single node or a loop shape One or more loops comprising one or more input units and one or more output units have a signal input from one input unit branched without being processed and output from all the output units A network system configured to be directly connected to a common transmission path, wherein a signal output from any of the nodes is transmitted to all nodes, and in each loop, the output of the own node among the nodes Can be extinguished by either the most downstream node, which is a node directly connected to the common transmission path, or the node that output the signal. Without a device, there is an effect that can realize a single node or loop-connected loops & Bath Mixed network system of nodes and multiple connections to one physical common medium.
[0045]
According to the present invention (Claim 2), it is composed of at least one loop composed of a plurality of nodes connected in a loop shape, and a single node or a plurality of nodes connected in a loop shape. One or more loops have one or more input units and one or more output units, and a signal input from one input unit is branched without being processed and is output from all the output units A network system configured to be directly connected to a transmission path, wherein the node that sent the signal extinguishes the signal returned to the own node, and the output side of the own node among the nodes of each loop When the most downstream node, which is a node directly connected to the common transmission path, belongs to the same loop as its own node, the node that sent the signal passes the signal and sends the signal When a node belongs to a different loop from its own node, the signal is extinguished, so that a single node or a group of nodes connected in a loop can be combined into one physical common medium without using a computer or a complicated control device. This has the effect of realizing a loop and bus mixed network system in which a plurality of connections are made.
[0046]
According to the present invention (Claim 3), it is configured by at least one loop composed of a plurality of nodes connected in a loop shape, and a single node or a plurality of nodes connected in a loop shape. One or more loops have one or more input units and one or more output units, and a signal input from one input unit is branched without being processed and is output from all the output units Each node that is directly connected to the transmission path and constitutes the loop has a node ID for recognizing its own node, and one node belonging to any of the plurality of loops becomes a token master node, and the token master A node other than the node that becomes the node becomes a slave node, and a node in which the output side of the node is directly connected to the common transmission path becomes the most downstream node. A receiving node that is a node ID of a node that should receive a transmitted data packet and a transmitting node ID that is a node ID of a node that is permitted to transmit the data packet A token transmission device that transmits a token packet including an ID, a token analysis device that analyzes the token packet, node setting information indicating whether or not the own node is the most downstream node, and a node ID of the token master node A storage device that temporarily stores received packet information; a data transmission device that performs data packet transmission; and a switch that discards or passes the received token packet, wherein the slave node includes the token packet The token analyzer that performs the analysis of the Node setting information indicating whether it is the most downstream node, a node ID of the token master node, a storage device that temporarily stores received packet information, a data transmission device that performs data packet transmission, and the received token A switch for discarding or passing a packet, and the token analysis device of each node causes the received token packet to be discarded when the token packet is transmitted if the node is a token master node. A loop in which the own node is the most downstream node as judged from the node setting information, and the own node is different from the token master node as judged from the node ID of the token master node and the node ID of the own node If it belongs to, discard the received token packet In other cases, the token packet is transmitted to all nodes, and the token packet is deleted from the network. In addition, when the data packet is transmitted, the switch is controlled so that the received data packet is discarded when the local node is the transmitting node as determined from the information of the received token packet, and is determined from the node setting information. If the own node is the most downstream node, and the own node belongs to a different loop from the sending node as judged from the received token packet information and the node ID of the own node, the received data packet is discarded. Control the switch, otherwise the received data By controlling the switch so as to pass the data packet, the data packet is transmitted to all the nodes so that the data packet is deleted from the network. There is an effect of realizing a loop and bus mixed network system in which a plurality of nodes or a group of nodes connected in a loop are connected to a physical common medium using a single optical star coupler.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of a network system according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a packet transmitted on the network in the network system according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a sequence in which packets are transmitted on the network in the network system according to the first embodiment of the present invention.
FIG. 4 is a diagram illustrating a switch state of each node and a token packet flow when a token packet is transmitted in the network system according to the first embodiment of the present invention.
FIG. 5 is a diagram illustrating a switch state of each node and a DS packet flow when a DS packet is transmitted in the network system according to the first embodiment of the present invention.
FIG. 6 is a diagram illustrating a switch state of each node and a data packet flow when the data packet is transmitted in the network system according to the first embodiment of the present invention.
FIG. 7 is a diagram showing a configuration for automatically recognizing a loop master by a signal line from an optical star coupler.
FIG. 8 is a diagram showing a configuration for performing initial setting by a setting device.
FIG. 9 is a diagram showing an example of information set in advance on the nonvolatile memory according to Embodiment 1 of the present invention;
FIG. 10 is a diagram showing an example of network connection by a conventional gateway.
[Explanation of symbols]
100 token master node
110 Loop master of loop 1
111 Slave node of loop 1
112 Slave node of loop 1
120 Loop master of loop 2
121 Slave node of loop 2
15 optical star coupler
21 token packet
22 DS packet
23 Data packets
31 token packets
32 DS packets
33 data packets
71 nodes
71a Signal detector for node 71
72 nodes
72a Node 72 Signal Detection Device
74 Signal line
75 Bus device composed of signal output device and optical star coupler
75a 75 signal output device
81 nodes
81a Storage device of node 81
82 Setting device
91 Example of information set in advance in nonvolatile memory
101 Bus network
101a Node connected to a bus network
102 Gateway or router
103 Loop network
103a Node connected to loop network

Claims (5)

At least one loop composed of a plurality of nodes connected in a loop, and one or more loops composed of a single node or a plurality of nodes connected in a loop form one or more inputs And a network system configured to have one or more output units and a signal input from one input unit branched without being processed and directly connected to a common transmission path output from all the output units There,
A signal output from one of the nodes is transmitted to all nodes, and in each loop, the most downstream node or the signal that is a node in which the output side of the own node is directly connected to the common transmission path among the nodes A network system characterized by being extinguished at any of the nodes that output. At least one loop composed of a plurality of nodes connected in a loop, and one or more loops composed of a single node or a plurality of nodes connected in a loop form one or more inputs And a network system configured to have one or more output units and a signal input from one input unit branched without being processed and directly connected to a common transmission path output from all the output units There,
The node that sent the signal extinguishes the signal returned to its own node,
The most downstream node of each loop in which the output side of the own node is directly connected to the common transmission path among the nodes, the node sending the signal belongs to the same loop as the own node A network system, wherein a signal is passed and the signal is extinguished when the node that sent the signal belongs to a different loop from the own node. At least one loop composed of a plurality of nodes connected in a loop, and one or more loops composed of a single node or a plurality of nodes connected in a loop form one or more inputs Each of which comprises a part and one or more output parts, is directly connected to a common transmission path that is branched without being processed and is output from all the output parts, and constitutes the loop Each node has a node ID for recognizing its own node, one node belonging to any of the plurality of loops becomes a token master node, and a node other than the node that becomes the token master node becomes a slave node, A network system in which the node directly connected to the common transmission path on the output side of the own node among the nodes is the most downstream node,
The token master node transmits a token packet including a transmission node ID that is a node ID of a node that is permitted to transmit a data packet and a reception node ID that is a node ID of a node that should receive the transmitted data packet. A token transmitting device that performs analysis of the token packet, node setting information indicating whether the own node is the most downstream node, a node ID of the token master node, and received packet information A storage device for storing data, a data transmission device for transmitting data packets, and a switch for discarding or passing the received token packet,
The slave node temporarily stores a token analysis device that analyzes the token packet, node setting information indicating whether the local node is the most downstream node, a node ID of the token master node, and received packet information. A storage device for storing data, a data transmission device for performing data packet transmission, and a switch for discarding or passing the received token packet,
The token analysis device of each node is
During the token packet transmission,
If the own node is a token master node, control the switch to discard the received token packet,
When the local node is the most downstream node as judged from the node setting information and the local node belongs to a different loop from the token master node as judged from the node ID of the token master node and the node ID of the local node Control the switch to discard the received token packet,
In other cases, by controlling the switch to pass the received token packet, the token packet is transmitted to all nodes and the token packet is extinguished from the network,
When transmitting the data packet,
Judging from the information of the received token packet, if the own node is a transmitting node, the switch is controlled so that the received data packet is discarded,
Received when the own node is the most downstream node as judged from the node setting information and the own node belongs to a different loop from the sending node as judged from the received token packet information and the node ID of the own node Control the switch to discard the received data packet,
In other cases, the network system is characterized in that the data packet is transmitted to all the nodes and disappears from the network by controlling the switch so as to pass the received data packet. The network system according to claim 3, wherein
The node ID has the same value between nodes belonging to the same loop, and includes a loop address that is different between nodes belonging to different loops. A network system characterized by determining whether or not it belongs. In the network system according to any one of claims 1 to 4,
The network system, wherein the common transmission path is an optical star coupler.

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