JP4851362B2 - Ring network system - Google Patents

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 particularly relates to determination of a transmission cycle when a frame is transmitted.

In a conventional ring network system, devices connected in a ring form transmit a communication frame at the transmission cycle timing of its own node.
For example, there are those disclosed in Patent Document 1 and RPR (Resilient Packet Ring) standardized by IEEE 802.17 as a ring network that can use IEEE 802.3 in the physical layer. RPR is briefly introduced in Non-Patent Document 1.

JP-A-8-70312 (pages 5-9, FIG. 1) Optcom, February / March 2005

In the conventional ring network system, since the communication frame is transmitted at the transmission cycle timing of the own node (transmission cycle is fixed), the transmission timing of all the nodes becomes asynchronous, the communication delay due to the communication frame collision increases, and the buffer memory If it exceeds, the frame may be discarded.
In industrial networks, high-speed and large-capacity communication is indispensable, and there is a need to avoid discarding frames when communication frames collide as much as possible. Therefore, if the transmission cycle is a fixed value (parameter), the maximum number of connected nodes For example, a communication cycle having a physical layer of 1 Gbps or the like has not been able to make the best use of its communication band.

Patent Document 1 describes a method of changing the transmission cycle in the ring-type multiplex transmission method, but since the technical field is in an automobile, it is a transmission cycle variable method for the purpose of reducing current consumption. When the node determines whether the node is activated or standby based on information in the frame and enters a standby state, the frame transmission cycle is extended.
In Patent Document 1, when each node is in a standby state as described above, the transmission cycle is merely extended, and the collision between the relay processing and the transmission processing of the own node is eliminated, and the frame is discarded. The transmission cycle was not adjusted to eliminate the.

  The present invention has been made to solve the above-described problems. The transmission cycle is adjusted, collision between the relay processing and the transmission processing of the own node is reduced, frame discard is reduced, and high speed is increased. The purpose is to obtain a ring network system capable of capacity communication.

In the ring network system according to the present invention, a ring network in which a plurality of nodes are connected in a ring shape via a transmission path to form a ring network, and each node asynchronously transmits a frame at its own transmission cycle. In the system, a node transmits a cyclic frame with its destination address and source address as its own node in a low cycle, and the cyclic delay when the frame goes around the ring network based on the delay from transmission to reception of the cyclic frame The amount is determined, and the transmission period is determined based on the determined amount of the cyclic delay.

  As described above, the present invention provides a ring network system in which a plurality of nodes are connected in a ring shape via a transmission path to form a ring network, and each node asynchronously transmits a frame in its own transmission cycle. In this case, the node transmits a cyclic frame having the destination address and the source address as its own node in a low cycle, and the cyclic delay amount when the frame goes around the ring network based on the delay from the transmission to the reception of the cyclic frame Since the transmission cycle is determined based on the obtained amount of the cyclic delay, the collision between the relay process and the transmission process can be reduced, and the frame discard can be reduced.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a ring network system according to Embodiment 1 of the present invention.
In FIG. 1, node devices 100 (100-1 to 100-n) are connected to a ring-shaped transmission line to constitute a ring network. In FIG. 1, node # 1 (100-1) operates as a transmission / reception node for circulating frames in the transmission path.

FIG. 2 is a diagram showing a format of a circulating frame on the transmission line of the ring network system according to the first embodiment of the present invention.
FIG. 2 shows an example in which an IEEE 802.3 physical header and an RPR (IEEE 802.17) RPR header are used. In the present invention, in the circulating frame, the address of the own node is put in both the destination address and the transmission source address in the RPR header, and the type indicating the circulating frame is put in the RPR header. The circulating frame transmitted by the node # 1 (100-1) is received by the node # 1 (100-1) after circulating around the ring, and the frame is discarded there.

FIG. 3 is a block diagram showing internal blocks of the node device of the ring network system according to the first embodiment of the present invention.
In FIG. 3, a frame input unit 110 to which a frame from the previous node is input, a buffer memory 111 in which the input frame is temporarily stored, a memory write control unit 112 that writes data in the buffer memory 111 to the data storage memory 118, A frame output unit 113 that outputs a frame from a node, a transmission selection unit 114 that selects a transmission frame and a relay frame of the node, a frame generation unit 115 that generates a frame to be transmitted by the node, and a memory that reads data from the data storage memory 118 Read control unit 116, frame relay unit 117 that relays the frame input to frame input unit 110 to frame output unit 113, timer unit 120 that measures the transmission cycle, and transmission of a frame when the timer value matches transmission cycle parameter 122 Transmission lap that makes a request Generator 121, and a transmission period parameter 122 which is the transmission period of at node start-up.

FIG. 4 is an image diagram showing a transition example of the delay time of the frame in the ring circulation of the ring network system according to the first embodiment of the present invention.
In FIG. 4, 100 is the same as in FIG. In FIG. 4, the accumulated delay time in the case of circulating in the ring is shown in parentheses of each node of transmission, relay, and reception. The transition example of the delay time until the circulation frame transmitted from the transmission / reception node which is one of the node devices circulates around the relay node and is received by the transmission / reception node again is shown.

FIG. 5 is a diagram showing processing timing of each node device when the ring type network system according to the first embodiment of the present invention circulates around the ring.
In FIG. 5, the horizontal axis indicates time passage, and the processing time of the transmission / relay / reception node is indicated by a horizontal bar. The processing timing is shown until the circulating frame transmitted from the transmitting / receiving node, which is one of the node devices, circulates around the relay node and is received by the transmitting / receiving node again.

  FIG. 6 is a flowchart showing the operation of the node device of the ring network system according to the first embodiment of the present invention.

Next, the operation will be described.
Hereinafter, a method for determining a transmission cycle when each node transmits a frame will be described. Here, the node # 1 (100-1) in FIG. 1 operates as a packet transmission / reception node that transmits a circular frame in the transmission path at a low cycle and receives this, and this node # 1 (100-) A case where 1) determines the transmission cycle will be described.
In FIG. 1, the node # 1 (100-1) set as the packet transmission / reception node sends a circular frame in the format shown in FIG. 2 in a low cycle according to the transmission cycle timing of the node, and sequentially connects them. When the frame is returned to the transmitted node # 1, the node # 1 discards the returned frame, and when the transmission cycle timing of the next round frame arrives, the round frame again And repeat this operation.

  In this process, the transmission cycle parameter 122 is used as the transmission cycle when the node is started up. And every time it receives a round frame transmitted by its own node, it updates the transmission cycle so that the round frame has a transmission cycle with a margin added to the delay time of the ring round (ring round trip delay). An optimal transmission cycle can be determined.

  Also, in this process, the ring circulation delay uses the accumulated delay in the ring in the circulation frame and the initial time in the node (initial delay time) that are updated each time the circulation frame is transmitted from the transmission node and the relay node. Is calculated. This is because the relay node adds the time at which the round frame is received to the intra-node initial time in the round frame, performs intra-node processing, and subtracts the intra-node initial time from the time output by the frame output unit 113. The processing time is calculated, and the cyclic frame is transmitted after the delay time obtained by adding the intra-node processing time to the cumulative delay in the ring (previous value) in the cyclic frame is changed to the next intra-ring cumulative delay (update value). In the transmission node, the transmission data is read from the data storage memory 118, the processing time in the node is added, and the cumulative delay in the ring is added at the time of output.

Next, details of the operation of the transmitting / receiving node will be described.
In FIG. 3, at the time of frame transmission, according to the transmission cycle parameter 122, the timer value counted by the timer unit 120 is sequentially compared, and when the timer value matches the transmission cycle parameter 122, the transmission cycle generation unit 121 requests transmission. Whenever there is this transmission request, the memory read control 116 reads the transmission data of its own node from the data storage memory 118, and in the case of a round frame, the frame generation unit 115 causes information such as a header including the initial time and type in the ring. And the frame output unit 113 adds the intra-ring accumulated delay to the circulating frame and transmits it to the next node via the transmission selection unit 114.

  At the time of frame reception, a frame is input via the frame input unit 110, and temporarily stored in the buffer memory 111 for speed adjustment, and is written in the data storage memory 118 by the memory write control unit 112. At this time, the circulating frame is discarded without being relayed to the next node. Further, the memory write control unit 112 determines the next transmission cycle after adding the accumulated delay in the ring in the circulating frame and the intra-node delay time from reception by the frame input unit 110 to writing to the data storage memory 118. (The determination method will be described later).

Next, details of the operation of the relay node will be described.
In FIG. 3, the frames received from the previous node are temporarily stored in the buffer memory 111 for speed adjustment via the frame input unit 110, and the frame relay unit 117 issues a relay request to the transmission selection unit 114 for permission. After being obtained, the communication frame in the buffer memory 111 is relayed to the next node via the frame output unit 113. At this time, the accumulated delay in the ring frame is updated by the frame output unit 113 in the same process as the transmission node.

Next, a transition example of the delay time of the circulating frame that circulates in the ring will be described.
As shown in FIG. 4, for example, assuming that the transmission node # 1 takes 2 μs for transmission processing and the subsequent relay nodes # 2 to #n take 3 μs uniformly, when receiving at the reception node # 1, a ring of 26 μs is obtained. For example, if it takes 4 μs in the reception process, the ring circulation delay takes 30 μs.
The next transmission cycle is calculated on the basis of such ring circulation delay.

Next, a method for calculating the transmission period from the ring circulation delay will be described with reference to FIG.
As shown in FIG.
Although it is calculated by transmission time + (relay time × number of relay nodes) + reception time, the time is not constant depending on whether or not there is a collision between the relay process and the transmission process (transmission / relay collision) at the relay node.
Therefore, a time obtained by adding the ring circulation delay Tr and the margin Tm is determined as the transmission cycle Ts. Although this margin Tm is a numerical value specific to the network system, for example, a collision time calculated in the worst case in which transmission / relay collision occurs in all relay nodes in the maximum number of connected nodes is set.

Next, the node operation will be described in detail with reference to the flowchart of FIG.
In FIG. 6, each node has a process when there is a received frame and a process when the timer value reaches the transmission cycle. Since these two processes are executed in parallel, the reception / relay / transmission process can be executed separately.
In FIG. 6, first, a node is started up (step S1). Next, the transmission cycle is initialized by acquiring the transmission cycle parameter 122 (step S2). Next, the timer unit 120 is activated (step S3). If there is a received frame (step S4), it is written in the buffer memory 111 (step S5), and the output selection by the transmission selection unit 114 waits until there is no transmission data (step S6). Is stored (step S7), and the received frame is relayed (step S8).
If there is no received frame in step S4, it is confirmed that the timer value has reached the transmission cycle (step S9), the current timer value is acquired (step S10), the transmission data is read from the data storage memory 118, A frame is generated based on (Step S12). If the timer value is not in the transmission cycle in step S9, the timer value is incremented (step S11), and the process returns to step S4.

Following the relay processing of the received frame in step S8, if the received frame is a circular frame, the previous value of the accumulated delay in the ring is acquired (step S13), and the current accumulated delay in the ring is greater than the previous accumulated delay in the ring. In this case (step S14), the transmission cycle is expanded (step S15), and the process returns to step S4. When the delay is not greater than the previous delay (step S14), the transmission cycle is shortened (step S16). Return to step S4.
After step S12, output selection is made as to whether relaying in step 8 or transmission in step S12 is performed (step S17), and in the case of a round frame, an intra-ring cumulative delay is added (step S18). Output (step S19). When transmission of all data is completed (step S20), the process returns to step S4. When transmission of all data is not completed, the process returns to step S12.

  According to the first embodiment, a node that transmits and receives a round frame calculates the accumulated delay time in the ring and increases or decreases the transmission cycle, thereby eliminating a useless time zone in which no communication frame is flowing and reducing the network communication bandwidth. You will be able to make the most of it.

Embodiment 2. FIG.
In the first embodiment, the transmission cycle is calculated from the inner ring delay, but in the second embodiment, the transmission timing is further shifted from the number of packets in the relay process to reduce the number of transmission / relay collisions. The circuit delay can be shortened.
FIG. 7 is a diagram for explaining how to determine the transmission timing of the ring network system according to the second embodiment of the present invention.
FIG. 7 shows an image in which the number of relay processing packets is counted for each transmission half cycle Ts / 2, and the phase of the transmission timing is shifted to the smaller number of relay processing packets in the first half and second half of the transmission cycle.

  FIG. 8 is a flowchart showing the operation of the node device of the ring network system according to the second embodiment of the present invention.

FIG. 9 is a block diagram showing internal blocks of the node device of the ring network system according to the second embodiment of the present invention.
In FIG. 9, reference numerals 110 to 118 and 120 to 122 are the same as those in FIG. In FIG. 9, a relay processing counter 123 that counts the number of relay processing packets based on the processing result of the frame relay unit 117 is provided.
In the second embodiment, the relay processing counter 123 is provided, and an instruction to shift the transmission timing to the smaller one in the first half cycle and the second half cycle is given to the transmission cycle generation unit 121. The transmission cycle generation unit 121 shifts the phase of the transmission timing in accordance with this instruction.

Next, the operation of the second embodiment will be described in more detail with reference to the flowchart of FIG.
Every time the transmission cycle becomes half cycle, the cumulative value of the number of relay processing packets sequentially calculated by the relay processing counter 123 is saved, the relay processing counter 123 is cleared, and every time the transmission cycle comes, it is saved last time Compare the accumulated value (accumulated value in the first half of the half cycle) with the current accumulated value (accumulated value in the second half of the half cycle), and if the number of packets in the first half of the half cycle is large, advance the phase of the transmission timing (Figure 7 is shifted to the right), and when the number of packets in the second half of the half cycle is large, the phase is delayed (shifted to the left in FIG. 7).

In FIG. 8, first, the transmission cycle is initially set (step S21). At this time, the default phase is set to zero. Next, the timer unit 120 is activated (step S22). The relay processing counter 123 starts counting the number of relay processing packets (step S23).
Depending on whether or not the half cycle of the transmission cycle has been reached (step S24), if the half cycle has not been reached, the timer value is incremented (step S25) to determine whether or not the half cycle has been reached (step S24), When the half cycle is reached, the cumulative value of the number of relay processing packets is saved and the relay processing counter 123 is cleared (step S26). Next, it is determined whether or not the timer value has reached the transmission cycle (step S27). If it is not the transmission cycle, the process returns to step S24. If it is the transmission cycle, the number of packets in the first half of the half cycle is the half cycle. Depending on whether the number of packets is greater than the latter half (step S28), the phase of the transmission timing is advanced (step S29) if it is larger, and if not, the phase of the transmission timing is delayed (step S30) and the process returns to step S24. .

  According to the second embodiment, the number of relay processing packets for each half cycle is compared to adjust whether the transmission timing is advanced or delayed, and transmitted when there is little relay processing to avoid transmission collision. .

Embodiment 3 FIG.
In the third embodiment, priorities are set for all nodes, packet collisions at relay nodes are counted for each priority, and the transmission cycle of each node is adjusted.
FIG. 10 is a diagram showing a format of a circulating frame on the transmission line of the ring network system according to the third embodiment of the present invention.
10, the priority of the own node is provided in the RPR / MAC header in the circulating frame of FIG. 2, and the number of high priority packet collisions, the number of medium priority packet collisions, the number of low priority packet collisions (hereinafter, High priority / medium priority / low priority packet collisions).

FIG. 11 is a block diagram showing internal blocks of the node device of the ring network system according to the third embodiment of the present invention.
In FIG. 11, reference numerals 110 to 118 and 120 to 122 are the same as those in FIG. In FIG. 11, a relay collision counter 124 that counts packet collisions in its own node and adds it to the circulating frame, and a priority determination unit that increases or decreases the transmission cycle by determining the cumulative number of collision packets for each priority. 125 is provided.

In the third embodiment, as shown in FIG. 10, the priority of the own node and the number of packets of the corresponding priority are counted up each time the circulating frame is relayed in the circulating frame. / Adds the number of medium priority / low priority packet collisions. The cyclic frame with these added is circulated in the ring so that each node increases or decreases the transmission cycle from the number of high priority / medium priority / low priority packet collisions each time a circular frame is received.
As a result, the number of transmission / relay collisions of a communication frame having a higher priority than that of the own node is reduced, the inner ring delay is shortened, and discarding of the communication frame with high priority is eliminated ( This occurs when the buffer memory 111 is full of data). The priority of the communication frame is unique to each network system. For example, the priority is classified into high priority / medium priority / low priority for each node, and the frame generation unit 115 adds the priority to the communication frame.

Next, this will be described in detail with reference to FIG.
First, in the transmission process, the frame generation unit 115 adds the priority of the own node to the circulating frame, and transmits after clearing the high priority / medium priority / low priority packet collision numbers to 0 respectively.
Next, in the relay node, every time the frame relay unit 117 competes with the transmission process in the transmission selection unit 114 and the relay process is awaited, the relay collision counter 124 refers to the priority of the own node and sets the priority. Relaying is performed by incrementing the number of packet collisions of the corresponding priority by +1 and writing it back to the circulating frame.

  Also, at the time of receiving and relaying a round frame, the relay collision counter 124 notifies the priority judgment unit 125 of the number of high priority / medium priority / low priority packet collisions of the relayed round frame, and the priority judgment unit 125. Then, the number of high priority / medium priority / low priority packet collisions is accumulated. When the number of packet collisions higher than the priority of the own node (for example, the higher priority is higher if the own node priority is medium priority) exceeds a certain threshold (for example, 10,000 packets per second), the transmission cycle is extended. Thus, when the number of packet collisions (for example, low priority) lower than the priority of the own node falls below a certain threshold (for example, 100 packets per second), processing for shortening the transmission cycle is performed.

  According to the third embodiment, each node is provided with a priority, thereby counting the number of packet collisions at the time of relaying for each priority, and each node prioritizing by adjusting the transmission cycle according to this priority. An appropriate transmission cycle can be set according to the degree.

Embodiment 4 FIG.
In the first and third embodiments, the optimal communication band is determined in the network system by increasing or decreasing the transmission cycle. However, in the fourth embodiment, for example, when the node is activated (for example, when the node is activated). If you want to speed up the update of communication data transmitted by other nodes, etc., or if you want to speed up or slow down the transmission cycle of a certain node, use the loop frame shown in FIG. It can be controlled.

FIG. 12 is a diagram showing a format of a circulating frame on the transmission line of the ring network system according to the fourth embodiment of the present invention.
In FIG. 12, in addition to the format of FIG. 10, a transmission cycle control node address indicating a transmission node whose transmission cycle is to be controlled, and a transmission cycle Up / Down instruction indicating how much the transmission cycle is increased or decreased (for example, 10 is transmitted by +10 μs) (Which extends the period) is provided in the payload.

FIG. 13 is a block diagram showing internal blocks of the node device of the ring network system according to the fourth embodiment of the present invention.
In FIG. 13, reference numerals 110 to 118, 120 to 122, 124, and 125 are the same as those in FIG. In FIG. 13, another node instruction determination unit 126 used when controlling the transmission cycle on the transmission node side on the reception node side, and another node instruction translation unit 127 that translates an instruction from the reception node side on the transmission node side are provided. ing.

The other node instruction determination unit 126 in FIG. 13 determines an event (for example, when a node is activated) whose transmission cycle is to be controlled, and notifies the frame generation unit 115 of the event, and the frame generation unit 115 transmits the transmission cycle control node address and the transmission. The period Up / Down instruction is added to the circulating frame and transmitted.
The circulation frame received by the receiving node (transmission cycle control node) via the relay node is transmitted to the other node instruction translating unit 127 from the transmission cycle control node address and the transmission cycle Up / Down instruction. The transmission period parameter 122 is changed and the transmission period generator 121 controls increase / decrease of the transmission period.

  According to the fourth embodiment, the transmission cycle on the transmission node side can be controlled from the reception node side.

Embodiment 5 FIG.
Embodiment 5 of the present invention will be described below with reference to FIG. 14 and FIG. 14 and FIGS.
FIG. 14 is an image diagram showing frame delay in the ring circulation of the ring network system according to the fifth embodiment of the present invention.
In FIG. 14, node devices 100 (100-1 to 100-4) are connected to a ring-shaped transmission line and have the configuration of n = 4 in FIG. Node # 1 (100-1) operates as a packet transmission / reception node in the transmission path.

The format of the frame flowing on the transmission line is the same as that in FIG. Here, a physical header of Ethernet (registered trademark) (IEEE 802.2) and an RPR header of RPR (IEEE 802.17) are used. In the present invention, the address of the own node is put in both the destination address and the source address in the RPR header, and a frame transmitted by a certain node # 1 (100-1) is circulated around the ring to transmit node # 1 (100 -1) and receive the frame there.

FIG. 15 is a block diagram showing an internal node block of the ring network system according to the fifth embodiment of the present invention.
In FIG. 15, reference numerals 110 to 118 and 120 to 122 are the same as those in FIG. In FIG. 15, a relay delay measuring unit 128 that measures the accumulated delay time after the frame is transmitted when the frame is relayed is provided.

FIG. 16 is a diagram showing the relay delay measurement contents of the ring network system according to the fifth embodiment of the present invention.
FIG. 16 shows the contents of the relay delay measuring unit 128 of FIG. Each time each of the nodes # 1 to # 4 relays a frame, it calculates and holds a delay time (cumulative relay delay time) after the frame is transmitted.

FIG. 17 is a diagram showing the processing timing of each node device when it circulates in the ring of the ring network system according to the fifth embodiment of the present invention.
FIG. 17 shows processing timings until frames transmitted by the nodes # 1 to # 4 in FIG. 14 respectively circulate around the relay node and are received again by the transmission / reception node.

Next, the operation will be described.
In FIG. 14, the node # 1 (100-1) set as the packet transmission / reception node sends out the frame of the format shown in FIG. 2 in accordance with the transmission cycle timing of the node, and sequentially connected next nodes When the frame is returned to the transmission source node # 1, the node # 1 discards the frame, transmits the frame again when the transmission cycle timing comes, and repeats the operation at first.

In this process, the transmission cycle timing uses the transmission cycle parameter 122 when the node is started up. However, every time a frame transmitted by each node is relayed, a cumulative delay time (cumulative time since the transmission of the frame) is transmitted. The relay delay measuring unit 128 that calculates the relay delay) calculates the own node transmission timing when all frames with the smallest cumulative relay delay are relayed, transmits the transmission timing to the transmission cycle generation unit 121, and determines the transmission cycle timing. Optimize.

In the above process, the intra-ring cumulative delay that is the basis for calculating the cumulative relay delay is calculated in the same manner as in the first embodiment, and is updated every time a frame is transmitted from the transmission / relay node. It is calculated using the internal accumulated delay and the initial delay time within the node.
That is, the node reads from the data storage memory 118 at the transmission node or adds the time when the frame is received at the relay node to the initial time within the node in the frame, performs the intra-node processing, and calculates the node from the time output by the frame output unit 113 After calculating the intra-node processing time minus the internal initial time and changing the delay time obtained by adding the intra-ring processing time in the frame (previous value) to the next intra-ring cumulative delay (updated value) Send a frame. The ring inner loop delay is calculated by the frame output unit 113, but the cumulative relay delay is calculated by the frame relay unit 117 using the same algorithm.

Next, details of the operation of the transmitting / receiving node will be described.
In FIG. 15, at the time of the first frame transmission, according to the transmission cycle parameter 122, the timer value counted by the timer unit 120 is sequentially compared, and the transmission cycle generation unit 121 requests transmission when the timer value matches the transmission cycle parameter 122. . Whenever there is this transmission request, the memory read control unit 116 reads the transmission data of its own node from the data storage memory 118, the frame generation unit 115 adds information such as the initial time in the ring and the header, and the transmission selection unit 114 Then, the frame output unit 113 adds the intra-ring accumulated delay to the frame and transmits it to the next node.
When a frame is received, 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 118 by the memory write control unit 112.
At this time, the frame is discarded without being relayed to the next node. Further, the memory write control unit 112 adds the intra-ring accumulated delay in the frame and the intra-node delay time from the reception by the frame input unit 110 to the writing to the data storage memory 118, and then registers the inner ring delay. However, in the present invention, the inner ring delay is not used. The initial frame transmission timing is determined by the transmission cycle parameter 122, but when the frame relay process is performed as time elapses, the frame is transmitted at the transmission cycle timing according to the cumulative relay delay. This operation will be described later.

Next, details of the operation of the relay node will be described.
In FIG. 15, the frame received from the previous node passes through the input unit 110 and is temporarily stored in the buffer memory 111 for speed adjustment, and the relay unit 117 issues a relay request to the transmission selection unit 114 to obtain permission. After that, the frame of the buffer memory 111 is relayed to the next node via the frame output unit 113. At this time, the intra-ring cumulative delay is updated by the frame output unit 113 by the same process as that of the transmission node.

Next, a transition example of the delay time of the frame that circulates in the ring will be described.
In FIG. 14, for example, if the transmission node # 1 takes 2 μs for transmission processing and the subsequent relay nodes # 2 to # 4 take 3 μs uniformly, when receiving at the reception node # 1, the accumulated delay in the ring is 11 μs. For example, if it takes 4 μs in the reception process, the ring circulation delay takes 15 μs. Based on this inner ring delay, the next cumulative relay delay is calculated.

Next, a transition example of the cumulative relay delay of a frame that circulates in the ring will be described.
In FIG. 14, since the frame transmitted by the node # 2 is relayed by the node # 1 via the node # 3 =># 4, the cumulative relay delay is 11 μs, and similarly, the node # 3 is 8 μs, the node # 4 is 5 μs.
These accumulated relay delays are calculated by the relay delay measuring unit 128 using the same algorithm as the ring inner loop delay of the first embodiment every time a frame passes through the relay unit 117, and a table as shown in FIG. 16 is generated. To do. Based on the created table, a frame transmitted from node # 4 with the smallest cumulative relay delay arrives and immediately after relaying (hereinafter, this timing is referred to as post-relay transmission timing), it can be recognized that the own node can transmit. . The next transmission timing is calculated based on the accumulated relay delay.

Next, a method for calculating transmission timing from post-relay transmission timing will be described.
In FIG. 17, the horizontal axis indicates the passage of time, and the processing times of the nodes # 1 to # 4 are indicated by horizontal bars. For example, when the node # 1 transmits a frame, the first transmission is performed according to the transmission cycle parameter 122, and the frame is discarded after being received by the own node # 1 via the nodes # 2 → # 3 → # 4.
Thereafter, the nodes # 2 to # 4 perform the same processing, the frame relay processing is performed at all the nodes, and the cumulative relay delay is registered. If the cumulative relay delay is registered, all nodes can know the timing at which the own node should transmit a frame based on the post-relay transmission timing. The post-relay transmission timing in FIG. 17 is # 4 for node # 1, # 1 for node # 2, # 2 for node # 3, and # 3 for node # 4. At this time, the transmission cycle generator 121 ignores the transmission request according to the transmission cycle parameter 122 when there is one or more post-relay transmission timings within the cycle set in the transmission cycle parameter 122.

According to the fifth embodiment, each node transmitting and receiving a frame calculates a cumulative relay delay and generates post-relay transmission timing, thereby eliminating frame transmission / relay collision and performing communication. In addition to eliminating data fluctuations, the transmission cycle can be speeded up so that the network communication band can be utilized to the maximum.

Embodiment 6 FIG.
In the fifth embodiment, the post-relay transmission timing is calculated from the cumulative relay delay. However, in the sixth embodiment, the post-relay transmission timing is generated in the order initially determined by the transmission cycle parameter 122, whereby the relay delay is calculated. Eliminates fluctuations in communication data and speeds up the transmission cycle without going through the complicated process of calculating

FIG. 18 is a block diagram showing an internal node block of the ring network system according to the sixth embodiment of the present invention.
In FIG. 18, reference numerals 110 to 118 and 120 to 122 are the same as those in FIG. In FIG. 18, based on the processing result of the relay unit 117, a relay processing trace unit 129 for recording the relayed frames in time series is provided, and transmission after relay is performed in the same manner as the relay delay measuring unit 128 of the fifth embodiment. A timing is generated, and a transmission timing at which the node transmits a frame is generated.

FIG. 19 is a diagram showing contents of relay processing traces in the ring network system according to the sixth embodiment of the present invention.
FIG. 19 shows the contents of the relay processing trace unit 129 in FIG. The transmission source nodes of frames arriving at each node are stored in chronological order.

FIG. 20 is a diagram showing the processing timing of each node when the ring type network system according to the sixth embodiment of the present invention circulates around the ring.
FIG. 20 shows processing timings until frames transmitted by the nodes # 1 to # 4 in FIG. 14 circulate around the relay node and are received by the transmitting / receiving node again.

Next, the operation will be described.
In FIG. 18, at the time of the first frame transmission, the transmission cycle generation unit 121 makes a transmission request when the timer value and the transmission cycle parameter 122 match by sequentially comparing with the timer value counted by the timer unit 120 according to the transmission cycle parameter 122. .
Since the transmission cycles of the nodes # 1 to # 4 are asynchronous, the arrival order of the frames to be relayed is random. This arrival order is recorded by the relay processing trace unit 129, and by knowing the transmission cycle timing according to the transmission cycle parameter 122, immediately after the local node recognizes the frame relayed immediately before transmitting the frame, and immediately after relaying this frame Is treated as the post-relay transmission timing. The following processing is the same as in the fifth embodiment.

Next, the processing operation of the relay processing trace unit 129 will be described with reference to FIG.
The first and last traces performed by the relay processing trace unit 129 are timings at which the own node requested by the transmission cycle generation unit 121 transmits a frame (time series order in FIG. 19 = 1 and 5). The relay processing trace unit 129 records the transmission source node in time series when the frames transmitted by the nodes # 2 to # 4 are relayed. FIG. 19 shows an example in which nodes # 4 → node # 2 → node # 3 are recorded in this order.
The order of frame relay traced by the relay processing trace unit 129 as described above is recognized as node # 4⇒ # 2⇒ # 3⇒ # 1 (own node), and the post-relay transmission timing of node # 1 is Assume that the frame transmitted by the node # 3 has just been relayed.

Next, a method for calculating transmission timing from post-relay transmission timing will be described.
In FIG. 20, the horizontal axis indicates the passage of time, and the processing times of the nodes # 1 to # 4 are indicated by horizontal bars.
For example, when the node # 1 transmits a frame, in the first transmission, the frame is transmitted according to the transmission cycle parameter 122, and the frame is discarded after reception by the local node # 1 via the node # 2 → # 3 → # 4. The
Thereafter, the nodes # 2 to # 4 perform the same processing, and the relay processing of one or more frames is performed at all the nodes, and the relay processing trace is registered. If the relay processing trace is registered, all nodes can know the timing at which the own node should transmit a frame based on the post-relay transmission timing.
The post-relay transmission timing in FIG. 20 is # 3 for node # 1, # 4 for node # 2, # 2 for node # 3, and # 1 for node # 4. At this time, the transmission cycle generator 121 ignores the transmission request according to the transmission cycle parameter 122 when there is one or more post-relay transmission timings within the cycle set in the transmission cycle parameter 122.

According to the sixth embodiment, in this way, at each node that transmits / receives and relays a frame, the relay processing trace is recorded and the transmission timing after relay is generated, thereby eliminating the frame transmission / relay collision. In addition to eliminating fluctuations in communication data, it is possible to maximize the network communication bandwidth by increasing the transmission timing.
Compared to the fifth embodiment, since the trouble of calculating the cumulative relay delay can be omitted, there is an advantage that can be achieved by relatively simple processing, but since the transmission order is random, the time that is wasted in the communication band There is also a disadvantage that occurs. For example, in FIG. 20, it is more efficient to transmit frame 2 by node # 4 between transmission of frame 4 by node # 3 and transmission of frame 1 by node # 1.

Embodiment 7 FIG.
In both of the fifth and sixth embodiments, when node # 4 in FIG. 14 suddenly leaves the network in a state of stable transmission according to the post-relay transmission timing, in the fifth embodiment, node # 1 (Node # 2 in the sixth embodiment) may not be able to transmit. Embodiment 7 deals with such a case.
FIG. 21 is a block diagram showing an internal node block of the ring network system according to the seventh embodiment of the present invention.
In FIG. 21, reference numerals 110 to 118, 120 to 122, and 128 are the same as those in FIG. In FIG. 21, a time-out measuring unit 130 for transmitting a time-out signal to the transmission cycle generating unit 121 when the post-relay transmission timing does not come within the transmission cycle set by the transmission cycle parameter 122 is provided, and within a predetermined transmission cycle. A network system capable of guaranteeing the transmission of the network is provided.

FIG. 22 is a diagram showing a processing timing of each node device when the ring network system according to the seventh embodiment of the present invention circulates around the ring.
In FIG. 22, the numbers indicate the frame numbers of FIG. FIG. 22 shows that even when the node # 4 leaves the network in FIG. 14, the nodes # 1 to # 3 do not stop transmitting within a predetermined transmission cycle, and the frames to be transmitted circulate around the relay node. The processing timing until the data is received again by the transmission / reception node.
Since the frame transmitted by the node # 4 does not reach the node # 1, the node # 1 transmits within a predetermined transmission cycle (transmission cycle Tp by parameter: initial value of the transmission cycle), so that the node It shows that transmission / reception is possible at # 1 to # 3.

According to the seventh embodiment, it is possible to provide a network system in which the timeout measuring unit 130 is provided and transmission within a predetermined transmission cycle can be guaranteed.

Embodiment 8 FIG.
In the seventh embodiment, it has been described that transmission / reception can be recovered within the transmission period set by the transmission period parameter 122 even when the node # 4 in FIG. 14 suddenly leaves the network. However, there is a problem that the transmission / reception recovery time is long. was there. On the other hand, in the eighth embodiment, the transmission / reception recovery time can be shortened by obtaining the shortest transmission cycle from the cumulative relay delay for the transmission / reception recovery time and, for example, by setting twice the shortest transmission cycle as the timeout value. I made it.

FIG. 23 is a block diagram showing an internal node block of the ring network system according to the eighth embodiment of the present invention.
In FIG. 23, 110-118, 120-122, 128, 130 are the same as those in FIG. In FIG. 23, the shortest transmission cycle Ts is calculated from the cumulative relay delay from the relay delay measuring unit 128 in the fifth embodiment, and the transmission cycle parameter 122 is automatically updated using, for example, twice the shortest transmission cycle Ts as a timeout value. A parameter update unit 131 is provided to shorten the transmission / reception recovery time.

FIG. 24 is a diagram showing the processing timing of each node device when it circulates in the ring of the ring network system according to the eighth embodiment of the present invention.
In FIG. 24, the numbers indicate the frame numbers in FIG.
FIG. 24 shows that even when node # 4 leaves the network in FIG. 14, the nodes # 1 to # 3 do not stop transmitting within the transmission period determined by the parameter update unit 131, and the frames to be transmitted are relay nodes. Is the processing timing from when the ring circulates until it is received by the transmitting / receiving node again.
The node # 1 transmits within the transmission cycle determined by the parameter updating unit 131 after the frame transmitted by the node # 4 has not arrived, indicating that the nodes # 1 to # 3 can continue to transmit and receive thereafter. ing.

According to the eighth embodiment, a network system that can shorten the transmission / reception recovery time by obtaining the shortest transmission cycle from the cumulative relay delay for the transmission / reception recovery time, for example, by setting the timeout value to twice the shortest transmission cycle. Can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the ring type network system by Embodiment 1 of this invention. It is a figure which shows the format of the circulation frame on the transmission line of the ring type network system by Embodiment 1 of this invention. It is a block diagram which shows the internal block of the node apparatus of the ring type network system by Embodiment 1 of this invention. It is an image figure which shows the transition example of the delay time of the frame in the ring circulation of the ring type network system by Embodiment 1 of this invention. It is a figure which shows the process timing of each node apparatus in the case of carrying out the ring circumference | surroundings of the ring type network system by Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the node apparatus of the ring type network system by Embodiment 1 of this invention. It is a figure explaining how to take the transmission timing of the ring type network system by Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the node apparatus of the ring type network system by Embodiment 2 of this invention. It is a block diagram which shows the internal block of the node apparatus of the ring type network system by Embodiment 2 of this invention. It is a figure which shows the format of the circulation frame on the transmission line of the ring type network system by Embodiment 3 of this invention. It is a block diagram which shows the internal block of the node apparatus of the ring type network system by Embodiment 3 of this invention. It is a figure which shows the format of the circulation frame on the transmission line of the ring type network system by Embodiment 4 of this invention. It is a block diagram which shows the internal block of the node apparatus of the ring type network system by Embodiment 4 of this invention. It is an image figure which shows the delay of the frame in the ring circulation of the ring type network system by Embodiment 5 of this invention. It is a block diagram which shows the node internal block of the ring type network system by Embodiment 5 of this invention. It is a figure which shows the relay delay measurement content of the ring type network system by Embodiment 5 of this invention. It is a figure which shows the process timing of each node apparatus in the case of carrying out the ring circulation of the ring type network system by Embodiment 5 of this invention. It is a block diagram which shows the node internal block of the ring type network system by Embodiment 6 of this invention. It is a figure which shows the relay processing trace content of the ring type network system by Embodiment 6 of this invention. It is a figure which shows the process timing of each node in the case of carrying out the ring circumference | surroundings of the ring type network system by Embodiment 6 of this invention. It is a block diagram which shows the node internal block of the ring type network system by Embodiment 7 of this invention. It is a figure which shows the processing timing of each node apparatus in the case of carrying out the ring circulation of the ring type network system by Embodiment 7 of this invention. It is a block diagram which shows the node internal block of the ring type network system by Embodiment 8 of this invention. It is a figure which shows the process timing of each node apparatus in the case of carrying out the ring circulation of the ring type network system by Embodiment 8 of this invention.

Explanation of symbols

100 nodes, 110 frame input section, 111 buffer memory,
112 memory write control unit, 113 frame output unit, 114 transmission selection unit,
115 frame generation unit, 116 memory read control unit, 117 relay unit,
118 data storage memory, 120 timer unit, 121 transmission cycle generation unit,
122 transmission cycle parameter, 123 relay processing counter,
124 relay collision counter, 125 priority determination unit,
126 Other node instruction determination unit, 127 Other node instruction translation unit,
128 relay delay measurement unit, 129 relay processing trace unit, 130 timeout measurement unit,
131 Parameter update unit.

Claims (4)

  In a ring network system in which a plurality of nodes are connected in a ring shape via a transmission path to form a ring network, and each node transmits frames asynchronously at its own transmission cycle, the node transmits a destination address and Based on the delay from transmission to reception of the circular frame, the cyclic frame with the original address as its own node is transmitted at a low cycle, and the cyclic delay amount when the frame goes around the ring network A ring network system, wherein the transmission period is determined based on the amount of cyclic delay performed.   In a ring network system in which a plurality of nodes are connected in a ring shape via a transmission path to form a ring network, and each node transmits a frame asynchronously with its own transmission cycle, the above nodes are connected to other nodes. A relay processing counter that counts the number of frames relayed each time a frame is relayed in the first half and second half of the transmission cycle, and the transmission cycle based on a cyclic delay amount when the frame goes around the ring network And the transmission timing of the own node is adjusted according to the first and second half of the transmission cycle of the relay processing counter.   When transmitting the round frame, the node adds its own priority and the number of packet collisions for each priority, and the other nodes that relay the round frame to which the priority is added transmit the frame and the relay. Each time a circulating frame competes, it counts up the number of packet collisions with a priority corresponding to its own priority, relays the circulating frame, and when each node receives the circulating frame, The ring network system according to claim 1, wherein the transmission period is increased or decreased according to the number of packet collisions.   The node adds information for increasing or decreasing the transmission cycle of another node to the circulating frame, and the other node receiving the circulating frame increases or decreases the transmission cycle according to the information. The ring network system according to claim 1 or 3.

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