JP2007208920A - Ring-type network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a clash of relay processing from a previous node to a subsequent node and transmission processing of its own node, and to eliminate a fluctuation of a data update cycle in a ring-type network system. <P>SOLUTION: A single node (100-1) is set as a transmission/discard node of a frame, and the other nodes connected are all set as general nodes. The transmission/discard node has a frame generator 114 for transmitting the frame to a network, a relay means 1118 for transmitting a communication frame having communication area portions #1-#n exclusive for each of all of the nodes, discarding the communication frame without being relayed when the communication frame is received by itself, and relaying the concerned frame to the subsequent node by the general nodes when the communication frame transmitted by e.g. the transmission/discard node is input, an own area timing detector 117 detecting an own area within a frame, and an own area data transmission controller 119 which puts own transmission data to its own area detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ring network system in which a plurality of communication nodes are connected in a ring shape via a transmission line to perform data communication, and in particular, for example, each of industrial cyclic data and image data, for example. It is suitable for a communication system that uses a general-purpose Ethernet (registered trademark) or the like in an application that requires a certain update period to update the data storage memory of a node to data transmitted from another node.

  In a conventional ring network system, an arbitrary connected device (node) among a large number of connected devices (nodes) connected in a ring shape via a transmission path can be transmitted to an arbitrary partner (node) at an arbitrary timing to transmit. Node).

  As such a ring network system, for example, a ring network system described in Japanese Patent Laid-Open No. 2002-77205 (Patent Document 1) or Ethernet (registered trademark) (IEEE802.3) is used for the physical layer. As a possible ring network, there is RPR (Resilient Packet Ring) (Non-patent Document 1) standardized by IEEE802.17. RPR is briefly introduced in the magazine “Optcom February / March 2005” (Non-Patent Document 2).

JP 2002-77205 A (FIG. 1 and its description) RPR (Resilient Packet Ring) standardized by IEEE802.17 Magazine "Optcom February / March 2005"

  A technical problem in the conventional ring network system will be described with reference to FIGS. FIG. 13 is a diagram showing a system configuration of a conventional ring network system. FIG. 14 is a block diagram showing an internal configuration of a node in a conventional ring network system.

  In FIG. 13, reference numerals 100-1 to 100-n denote a plurality of nodes connected on the transmission line 1. In FIG. 13, node # 1 (100-1) is node #n (100-n). ) And a node # 3 (100-3) is about to send a frame to the node # 7 (100-7).

  FIG. 14 shows an internal block diagram of the node # 3 (100-3) in the node in FIG. 13. The node includes a frame input unit 110, a buffer memory 111, and a frame data capture control unit 112. A frame output unit 113, a frame data transmission control unit 115, a data storage memory 116, and an output data selection unit 118.

  In the node # 3 (100-3), the frame entered from the frame input unit 110 is written to the internal memory (that is, the data storage memory 116) via the buffer memory 111 and is to be relayed to the next node. timing, and when to send is read from the data storage memory to spontaneously transmit its data overlap (collision occurs) and, either the processing can not be output both data simultaneously waited As a result, the data update cycle in which the data storage memory 116 of each node is updated to data transmitted from another node will vary.

  The present invention has been made to solve the above-described conventional problems, and eliminates the conflict between the relay process from the previous node to the next node and the transmission process of the own node, and the conventional data update cycle. An object is to obtain a ring network system that eliminates fluctuations in the network.

  The ring network system according to the present invention is a ring network system in which a plurality of communication nodes are connected in a ring shape via a transmission line to perform data communication, and one node is set as a communication frame transmission / discard node. In addition, all other connected nodes are set as normal nodes, and the transmission / discard node has a frame generation unit for transmitting a communication frame on the network and has a dedicated communication area for all nodes. When the communication frame is sent by itself and discarded without being relayed to the next node, the normal node receives the communication frame transmitted by the transmission / discard node. The relay means for relaying the communication frame to the next node and the own area for detecting the own area in the communication frame. Those which comprise a self-area data transmission control unit for placing a self-transmission data to the own region detected a timing detection unit.

  According to the present invention, in a ring network system in which a plurality of communication nodes are connected in a ring shape via a transmission line to perform data communication, one node is set as a communication frame transmission / discard node, and the other All connected nodes are set as normal nodes, and the transmission / discard node has a frame generation unit for transmitting a communication frame on the network, and a communication frame provided with dedicated communication area units for all nodes. When the communication frame is received by itself, it is discarded without being relayed to the next node, and the normal node receives the communication frame when the communication frame transmitted by the transmission / discard node is input. Relay means for relaying to the next node, own area timing detection unit for detecting the own area in the communication frame, and detected own area Since it has its own area data transmission control unit for carrying its own transmission data, there is no collision between the relay process from the previous node to the next node and the transmission process of the own node, and there is an effect that the fluctuation of the data update cycle is eliminated. .

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a diagram showing an example of a system configuration of a ring network system, FIG. 2 is a diagram showing an example of a frame format, FIG. 3 is a block diagram showing an example of an internal configuration of a transmitting node, and FIG. 4 is an internal configuration of a normal node It is a block diagram which shows the example of. In addition, in each figure, the same code | symbol shows the same part.

In FIG. 1, among a plurality of node devices (100-1) to (100-n) connected on the transmission line 1, node # 1 (100-1) is the only packet transmission / transmission in the transmission line 1. Set as a discard node.

  The example of the frame format illustrated in FIG. 2 shows an example of the format of the frame that flows on the transmission path 1, and here, the physical header of Ethernet (registered trademark) (IEEE802.2) and the RPR header of RPR (IEEE802.17). An example using is shown. In the first embodiment, the address of the own node is put in both the destination address and the source address in the RPR header, and the communication area dedicated to all nodes connected to the transmission path in the data part following the header, that is, A region for # 1 to a region for #n are provided individually. The dedicated communication areas (areas for # 1 to #n) of each node in the frame are all the same size as shown in FIG. As shown in FIG. 2, there is a known physical header at the front end of the frame, and a known FCS (frame check sequence) at the rear end.

  FIG. 3 is an internal block diagram of the packet transmission / discard node set in node # 1 (100-1) in FIG. 1, and shows a frame input unit 110, a buffer memory 111, and a frame data capture control unit. 112, a frame output unit 113, a frame generation unit 114, a frame data transmission control unit 115, and a data storage memory 116 are provided.

FIG. 4 shows an internal block diagram of node # 3 (100-3), which is a normal node other than the transmission / discard node in FIG. 1. Compared with FIG. 3, the frame generation unit 114 is deleted. And
A local area timing detection unit 117 for detecting the local area in the frame;
The data to be sent to the output unit 113 is relay data sent from the previous node and relayed to the next node, and the own region transmission data taken out from the data storage memory 116 in the own node by the own region data sending control unit 119 and sent. An output data selection unit 118 to select from
The own area data transmission control unit 119;
A path 1118 from the buffer memory 111 to the output data selection unit 118;
Is added.

  Each node (100-1) to (100-n) in FIG. 1 has one transmission port Po1 and one reception port Pi1, as shown in FIGS. The frame is flowed only in one direction on 1.

  Next, the operation will be described.

  In FIG. 1, node # 1 (100-1) set as a packet transmission / discard node sends out a frame of the format shown in FIG. 2 at the start of communication and relays it to the next connected node in sequence. When the frame is returned to the transmitting node # 1, the node # 1 discards the frame, transmits the frame again, and repeats the operation. That is, in the first embodiment, the sending / discarding node issues one frame (frame (1)) as shown in FIG. Discard the frame (frame (1)) and issue the next frame (frame (2)).

  In the above process, when a normal node other than the packet sending / discarding node owns the transmission data, it waits for the reception of the frame without sending a new frame, and when the frame is received, it is determined within the frame. By overwriting the own area transmission data in the data storage memory 116 to the own area, the own data is transmitted over the network.

  Next, details of the operation of the transmission / discard node will be described with reference to FIG.

  In FIG. 3, at the time of frame transmission, data of all nodes is read from the data storage memory 116 by the memory read control 115, information such as a header is added by the frame generation unit 114, and transmitted to the next node via the frame output unit 113. . When receiving a frame, it is input via the frame input unit 110, temporarily stored in the buffer memory 111 for speed adjustment, and written in the data storage memory 116 by the frame data fetch control unit 112. At this time, the frame is discarded without being relayed to the next node, and is regenerated at the time of transmission.

  Next, details of the operation of the normal node will be described with reference to FIG.

  FIG. 4 shows the inside of the node # 3 as an example. Frames relayed from the previous node are temporarily stored in the buffer memory 111 for speed adjustment via the input unit 110, and simultaneously the data of the entire area is written in the data storage memory 116 by the frame data fetch control unit 112, and at the same time the output data selection unit 118, and relayed to the next node via the frame output unit 113. At this time, the local area data transmission control unit 119 reads the data of the local node area in the data storage memory, and the local area timing detection unit 117 sets the output data selection unit 118 from the relay side only at the timing of the local area of the frame. By switching to the transmission data side, the portion of the own area in the frame is updated to the data of the area of the own node in the data storage memory. That is, the local area in the frame relayed by the normal node to the next node is updated to the transmission data of that node.

  That is, Embodiment 1 of the present invention is a ring network system in which a plurality of communication nodes (100-1) to (100-n) are connected in a ring shape via a transmission line 1 to perform data communication. One node, eg (100-1), is set as the frame send / discard node (eg FIG. 3) and the other connected nodes, eg (100-2) to (100-n) are all As a normal node (for example, FIG. 4), the transmission / discard node (for example, (100-1)) includes a frame generation unit 114 for transmitting a frame on the network as illustrated in FIG. A communication frame provided with dedicated communication area units # 1 to #n for all nodes (100-1) to (100-n) was sent and received by the user himself / herself. Is discarded without relaying to the next node, and the normal nodes, for example (100-2) to (100-n), are transmitted / discarded nodes, for example (100-1), for example, as shown in FIG. When the communication frame transmitted by is input, the relay means 1118 for relaying the frame to the next node, the own region timing detection unit 117 for detecting the own region in the frame, and the own transmission data are put on the detected own region. This is a ring network system including a local area data transmission control unit 119.

  In this way, there is only one node that transmits a frame in the transmission path, so that there is no collision between the relay data from the previous node and the transmission timing of its own transmission data in the node, and the processing time at each node Therefore, there is no fluctuation in the data update time to the internal memory (data storage memory 116 in FIG. 4) of the data transmitted from other nodes in each node, and the internal memory is always in a fixed time. Data can be updated to

Embodiment 2. FIG.
The second embodiment of the present invention will be described below with reference to FIG.

  In the first embodiment of the present invention described above, the case where the dedicated communication areas of each node in the frame are all the same size and the areas of all connection nodes are provided, but in the second embodiment of the present invention, As shown in FIG. 6, storage data information indicating whether or not the communication data of each connected node exists in the communication frame is provided in the frame, and corresponds to the communication area in the frame at the time of frame transmission. The stored data information is set, and when a normal node receives a communication frame, it is stored in the data storage memory 116 with reference to the content of the stored data information, so it is necessary to provide an area for all nodes in one frame. The area of one node can be made larger, and the area of an arbitrary node can be set or omitted depending on the communication load.

  FIG. 6 shows an example of the frame format in the second embodiment. The first frame includes communication areas for node # 1, node # 2, node # 4, and node # 5. The second frame is provided with communication areas for node # 8, node # 11, node # 12, and node # 19, and the third frame is for node # 20, for node # 23, Communication areas for the node # 24 and the node # 28 are provided, and the storage data information of the third frame corresponds to the node # 20, the node # 23, the node # 24, and the node # 28. The node number of the stored communication area is shown by setting 1 to a location and setting 0 to other locations.

  The normal node that has received the frame from another node stores the corresponding data in the received frame in the data storage memory 116 only for the node number that is set to 1 with reference to the stored data information. Only when there is any data, the data of the own node in the data storage memory 116 is overwritten and updated.

  Thus, the second embodiment of the present invention is the storage data information indicating whether or not the communication data of each connected node is present in the communication frame in the first embodiment of the present invention. (See FIG. 6), and when the normal node receives a communication frame, the normal node refers to the content of the stored data information to recognize its own communication area, and stores it in the data storage memory 116 (see FIG. 4). This is a ring network system.

Embodiment 3 FIG.
A third embodiment of the present invention will be described below with reference to FIGS.

  Instead of the above-described second embodiment of the present invention, as shown in FIG. 7, the node number of the communication area part existing in the communication frame and the offset that becomes the start address when the communication area part is stored in the memory Since the information and the data size of the communication area portion are stored in the storage data area, and when the normal node receives the communication frame, it is stored in the data storage memory 116 with reference to the contents of the stored data information. In addition to the effect of the second embodiment of the present invention described above, the size of each communication area can be made variable depending on the communication load status and the type of data handled by each node.

  FIG. 7 shows an example of the frame format according to the third embodiment. The first frame includes communication areas for node # 1, node # 2, node # 4, and node # 5. The second frame is provided with communication areas for node # 8, node # 12, and node # 19, and the third frame is for node # 20, for node # 23, and for node # 24. A communication area is provided, and the stored data information of the third frame includes offset information and a communication area that are the head addresses when the data is stored in the respective memories for the node # 20, the node # 23, and the node # 24. Set data size.

  FIG. 8 is a diagram showing an image when a normal node that has received the frame and stored data information stores data in the data storage memory 116. The size is determined from the address indicated by the offset information of the communication area of each node. Store as much data as shown.

  As described above, the third embodiment of the present invention further stores the node number of the communication area portion and the communication area portion existing in the communication frame in the memory in the first embodiment of the present invention. Storage data information (see FIG. 7) that stores the offset information that becomes the leading address and the data size of the communication area is provided, and the normal node refers to the contents of the stored data information when receiving the communication frame. This is a ring network system that recognizes its own communication area and stores it in the data storage memory 116.

Embodiment 4 FIG.
The fourth embodiment of the present invention will be described below with reference to FIG. 9, which is an explanatory diagram of frame issue intervals.

  In the above-described first embodiment of the present invention, as shown in FIG. 5, after the transmission / discard node issues one frame (frame (1)), it circulates all the nodes and returns to itself. Assuming that the next frame (frame (2)) is issued, as shown in FIG. 9, before the transmitted frame (frame (1)) is returned, the next frame (frame (2)) is assumed. ) And send the next frame (frame (3)) before the next frame (frame (2)) is returned in the same way, and shorten the frame transmission interval to improve communication efficiency. it can.

Here, since the minimum frame transmission interval needs to be longer than the processing time of at least one node, it is determined by the following procedure, for example.
1. To determine the transmission interval, the transmission / discard node sends a test frame and starts a time monitoring timer.
2. Each node processes the same as a normal data frame and relays it to the next node.
3. When the frame sent to the sending / discarding node is returned, the time (time from sending the test frame to returning) is confirmed, and one each time it passes through the node in the RPR header. Recognize the number of connected nodes from the decreasing TTL (Time To Live) information, calculate the processing time of one node by the formula of (frame lap time) ÷ (number of connected nodes), and send the minimum frame The interval is determined to be more than that.

  As described above, the fourth embodiment of the present invention is the same as the first embodiment of the present invention described above, in which the transmission / discard node further determines a frame transmission interval determination unit (determining an optimum timing for transmitting a communication frame). A ring network system that sequentially issues frames at determined intervals.

Embodiment 5 FIG.
A fifth embodiment of the present invention will be described below with reference to FIGS. FIG. 10 is a diagram showing another example of the system configuration of the ring network system, and FIG. 11 is a block diagram showing an example of the internal configuration of the normal node.

  In the first embodiment of the present invention described above, each node has one transmission port Po1 and one reception port Pi1, and a mode is described in which a frame is flowed only in one direction on the ring-shaped transmission line 1. However, in RPR (IEEE802.17), each node has two transmission ports and two reception ports (Po1, Po2, Pi1, Pi2), and forms two rings with different communication directions. The method (2) for communicating using the two rings will be described.

  In FIG. 10, node # 1, which is a transmission / discard node, has a clockwise direction that continues with node # 2, node # 3, and a counterclockwise direction that continues with node #n, node # n-1,. The normal node compares the contents of both the data inputted from the clockwise side and the counterclockwise side when the frame is received and fetches it only when they coincide with each other, and the data storage memory 116 (see FIG. 11). ), It is possible to improve the communication quality by duplicating the transmission path.

  In the node according to the fifth embodiment of the present invention, as shown in FIG. 11, the data input unit 110, the data output unit 113, the buffer memory 111, and the output data, which are one each in the first embodiment of the present invention described above. Each of the selection units 118 (110a, 110b, 113a, 113b, 111a, 111b, 118a, 118b) includes a data comparison unit 120 provided between the buffer memories 111a, 111b and the data storage memory 116, and a buffer memory. Before writing to the data storage memory 116 from 111a, 111b, the data comparison unit 120 compares both data contents inputted from the clockwise side and the counterclockwise side, and determines whether or not the two data contents match. As a result of the determination, the data storage memory 116 is fetched only when they match. The process to write to refer to FIG. 11).

  As described above, according to the fifth embodiment of the present invention, each communication node has two sets of input / output ports Pi1, Pi2, Po1, and Po2, each of which has a different ring in which the direction in which data passes is opposite to each other. The transmission / discard node is the same for two different ports, in other words each connected to a ring-shaped transmission line defined to pass data in opposite directions. The normal node is a ring type network system that includes a frame comparison unit that compares the contents of frames input from two different ports and writes them to the internal memory if they match as a result of comparison.

Embodiment 6 FIG.
The fifth embodiment of the present invention will be described below with reference to FIG. 12, which is a flowchart showing a transmission node determination flow.

  In the above-described first embodiment of the present invention, it is assumed that the transmission / discard node is set in advance at the time of system construction, but the sixth embodiment of the present invention is a case where the transmission / discard node is automatically determined at the time of startup. In this example, as shown in FIG. 12, when all the nodes have risen (step ST1), node IDs unique to each node are transmitted (step ST2), and the timer is started (step ST2). After step ST3), it is determined whether there is received data (step ST4).

  If there is received data as a result of the determination in step ST4, it is next determined whether or not the data has been transmitted (step ST5). If the result of the determination in step ST5 is not the data that has been transmitted, the receiving node It is determined whether or not the ID is larger than its own node ID (step ST6). If the result of determination in step ST6 is that the receiving node ID is larger than its own node ID, it is relayed (step ST7), and if it is smaller, it is discarded (step ST8). )

  If the node ID is larger than its own node ID, processing is performed with an algorithm of relaying and discarding if it is smaller. The node that circulates all the nodes on the ring and receives the frame transmitted by itself in the determination in step ST5 is the transmitting node ( In step ST9), if there is no received data as a result of the determination in step ST4, an operation is performed so as to become a normal node (step ST11) if no frame is returned within a certain time determined by the timer count-up (step ST10). The transmission node is automatically determined.

  As described above, according to the sixth embodiment of the present invention, all nodes connected to the ring-shaped transmission line have a means (function) for transmitting a transmission node determination frame including its own node number and a transmission node from another node. A means (function) for comparing its own node number with the received node number when receiving a decision frame and a means (function) for monitoring a timer after sending a transmission node decision frame are transmitted / discarded from the connected nodes. This is a ring network system that automatically determines nodes.

  In this way, the transmission node and the normal node can be configured with the same hardware, and can be reliably set without artificial setting such as a switch.

It is a figure which shows Embodiment 1 of this invention, and is a figure which shows the example of the system configuration | structure of a ring type network system. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows the example of a frame format. It is a figure which shows Embodiment 1 of this invention, and is a block diagram which shows the example of the internal structure of a transmission node. It is a figure which shows Embodiment 1 of this invention, and is a block diagram which shows the example of the internal structure of a normal node. It is a figure which shows Embodiment 1 of this invention, and is explanatory drawing of a frame issue space | interval. It is a figure which shows Embodiment 2 of this invention, and is a figure which shows the other example of a frame format. It is a figure which shows Embodiment 3 of this invention, and is a figure which shows the other example of a frame format. It is a figure which shows Embodiment 3 of this invention, and shows the example of a data storage memory storage image. It is a figure which shows Embodiment 4 of this invention, and is explanatory drawing of a frame issue space | interval. It is a figure which shows Embodiment 5 of this invention, and is a figure which shows the other example of the system configuration | structure of a ring type network system. It is a figure which shows Embodiment 5 of this invention, and is a block diagram which shows the example of the internal structure of a normal node. It is a figure which shows Embodiment 6 of this invention, and is a flowchart which shows a transmission node determination flow. It is a figure which shows the system configuration | structure of the conventional ring type network system. It is a block diagram which shows the internal structure of the node of the conventional ring type network system.

Explanation of symbols

1 transmission line,
100-1 to 100-n nodes,
Pi1, Pi2, Po1, Po2 ports,
110, 110a, 110b input unit,
111, 111a, 111b buffer memory,
112 frame data capture control unit,
113, 113a, 113b output section,
114 frame generator,
115 frame data transmission control unit,
116 data storage memory,
117 own area timing detection unit,
118, 118a, 118b output data selection unit,
1118 route,
119 own area data transmission control unit,
120 Data comparison unit.

Claims (6)

In a ring network system in which a plurality of communication nodes are connected in a ring shape via a transmission line and perform data communication,
One node is set as a transmission / discard node for communication frames, and all other connected nodes are set as normal nodes.
The transmitting / discarding node has a frame generation unit for transmitting a communication frame on the network, and transmits a communication frame provided with a dedicated communication area unit for all nodes and receives the communication frame by itself. When discarding without relaying to the next node,
The normal node includes a relay unit that relays the communication frame to a next node when the communication frame transmitted from the transmission / discard node is input, and a local area timing detection unit that detects the local area in the communication frame; A ring network system, comprising: a local area data transmission control unit that puts own transmission data on the detected local area. The ring network system according to claim 1,
Storage data information indicating whether or not communication data of each connected node exists in the communication frame is provided in the frame, and the normal node receives the communication frame when the communication data is received. A ring network system characterized by recognizing its own communication area by referring to its contents and storing it in a memory. The ring network system according to claim 1,
Stored data information in which the node number of the communication area part existing in the communication frame, offset information serving as a head address when the communication area part is stored in a memory, and the data size of the communication area part are stored in the frame Provided in the
When the normal node receives the communication frame, the normal node recognizes its own communication area by referring to the contents of the stored data information and stores it in a memory. In the ring network system according to any one of claims 1 to 3,
The ring network system, wherein the transmission / discard node has a frame transmission interval determination function for determining a timing for transmitting the communication frame, and issues frames at the determined interval. In the ring network system according to any one of claims 1 to 4,
Each communication node has two sets of input / output ports, each connected to a ring-shaped transmission line defined to pass data in opposite directions,
The sending / discarding node sends the same frame to two different ports;
The ring network system characterized in that the normal node includes a frame comparison unit that compares the contents of frames input from two different ports, and writes them in an internal memory if they match as a result of the comparison. In the ring network system according to any one of claims 1 to 5,
All nodes connected to the ring-shaped transmission line have a function of transmitting a transmission node determination frame including its own node number, and a node that has received its own node number when receiving a transmission node determination frame from another node. A function for comparing numbers, and a function for monitoring a timer after transmitting a transmission node determination frame,
A ring network system, wherein a transmission / discard node is automatically determined from connected nodes.

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