JPH01291550A - Multi-address communication system - Google Patents

Abstract

PURPOSE:To prevent the residence of a frame from being generated by comparing a timer value in a received communication frame with the one stored in a timer value table classified by every transmission origin, and diciding whether the received communication frame should be deleted or transmitted to another node. CONSTITUTION:The timer value is checked at a timer value check part 121 by using the timer value table 122 classified by every transmission origin. In the timer value table 122 classified by every transmission origin, the latest timer value classified by every transmission origin is stored, and the timer value of a node corresponding to the timer table 122 classified by every transmission origin is read out from a transmission origin address in a reception frame, then, it is compared with the timer value 183 in the frame. When the timer value in the reception frame is larger than that of the frame, it is identified as an effective frame, and the timer value of the transmission origin is rewritten by the timer value in the reception frame by a table update part 124. When the timer value in the reception frame is equal to or less than the timer value in the timer table 122 classified by every transmission origin, it is deleted, and no transmission to another node is performed.

Description

[Detailed Description of the Invention] [Summary] Regarding a broadcast communication method in a mesh network in which a plurality of nodes are connected in a mesh pattern, frame retention does not occur when communication is performed using broadcast frames in the mesh network. The purpose is to provide a broadcast communication method in a mesh network, in which multiple nodes are connected in a mesh shape through communication lines.
In the broadcast communication method in the mesh network, in which each node transmits communication frames transmitted from other nodes to other nodes, the transmitting section of each node is equipped with a timer that displays the time including the year, month, and day, and The destination address, the source address, and the timer value at that time are added to the information section of the communication frame sent from the node, and the receiving section of each node transmits the timer value in the received communication frame at the timer value checking section. The communication frame is compared with the timer value stored in the source timer value table, and depending on the result, it is determined whether to discard the received communication frame or to transmit it to another node.

[Industrial Application Field] The present invention relates to a network system in which a plurality of nodes are connected in a mesh-like manner.
Concerning the broadcast communication system in synchronization work.

2. Description of the Related Art In communication technology, a plurality of nodes (communication devices) are connected in a mesh pattern to perform communication between the nodes. Specifically, when transmitting and receiving information between higher-level devices (terminals, computers, etc.) connected to nodes, when transmitting information for monitoring the status of communication devices that make up each node of the Mensch network, etc. It is used in Connecting lines between multiple nodes in a mesh-like manner means that there are multiple routes between nodes, and has the advantage that if a line between some nodes fails, connection can be made using another route. . However, when performing broadcast communication in this mesh network, there is a problem that the same frame stays in the network and the same frame is received multiple times, and an improvement is desired.

[Prior Art] An explanatory diagram of a conventional mensch network communication system is shown in FIG.

In the mesh network, each node A to D is connected by a line as shown in the figure, and each node is connected to a host device such as a terminal or a computer.

In the communication method of Conventional Example 1 shown in FIG. Communication is carried out using a fixed route. In this case, when node A communicates with another node, for example with node D, node A polls node B via route . Then, node B polls node C via route 2 according to the table, and then re-polles from node C to node D via route 2, and is connected in turn.

Next, the communication method of Conventional Example 2 shown in FIG. It is transmitted via the route indicated by the chain line 1'. Then,
Nodes B and C import the information into their own nodes and transmit a broadcast frame with the same content to all nodes other than the other party that sent the information. That is, node B has nodes C and D
The data is transmitted to nodes B and D via a route indicated by a solid line 2, and from node C to nodes B and D via a route indicated by a dashed-dotted line 2'.

[Problems to be Solved by the Invention] According to the method of Conventional Example 1 described above, when a failure occurs in a part of the fixed route, it is necessary to rewrite the contents of the table in order to change to another route. Although it is possible to deal with this problem when the number of nodes is small, in the case of a system with a huge number of nodes, there is a problem in that processing for changing routes and selecting the optimal route requires time and effort. .

Furthermore, according to the method of Conventional Example 2 described above, as is clear from FIG. 5B (for example, numbers 3 and 3' are the second communication of the same frame), the same frame circulates within the network. There was a problem in that frames were retained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a broadcast communication system in a mesh network in which frame retention does not occur when communication is performed using broadcast frames in the mesh network.

[Means for Solving the Problems] A basic configuration diagram of a node according to the present invention is shown in FIG. 1+a+, and a diagram showing a broadcast frame format according to the present invention is shown in FIG. 1(b).

First of all, to explain about FIG.
), 17 is the control section (C), 18 is the information section (1), 1.9
is the frame check sequence part (Fe2), 2
0 represents a flag portion (F).

This frame format is the well-known HDLC (formerly GH
Level Data Link Control P
rocedure) method. In the present invention, the destination address (DN>18) is stored in the information section 18(1).
1, timer value 1 along with source address (SN) 182
83 is added to the frame. In addition,
The address part (A) is used in transmission between two points, and in the present invention is used when transmitting a frame to an adjacent node.

In the basic configuration diagram of FIG. A timer that displays seconds; 112 is a transmission frame creation section; 121 in the reception section 12 is a timer value check section; 1
Reference numeral 22 represents a transmission bereavement timer value table, 123 represents a transmission source check unit, and 124 represents a table update unit.

The present invention adds a timer value to a communication frame at the transmission source, and each node is provided with a table storing the latest timer value for each other transmission node, and the timer value of the received frame is stored in the table. By comparing the frame with the latest timer value, it is possible to identify whether the frame is a new frame or a frame that has already been received, and to control whether to discard it or transfer it to another frame.

[Operation] To explain the operation of the basic configuration of FIG. Start.

The transmitter 11 transmits the first frame in the broadcast frame generator 112.
A transmission frame in the picture frame format shown in Figure fbl is created. In that case, the information part 1B(1) of the frame
The current timer value displayed by the timer 111 is read together with the destination address 181 and source address 182 of the frame, and is set to the timer value 183 of the frame. The transmission frame creation unit 112 then generates data 184, Fe219
, sets the flag 20, creates a transmission frame shown in FIG. 1 (bl), and transmits it to the line.

When receiving a communication frame from the line in the receiving section (2), the frame is first checked for the source of the frame, and if the own node is the source, the frame is discarded. If the own node is not the source, the timer value check unit 121
The timer value is checked using the transmission bereavement timer value table 122. Transmission bereavement timer value table 12
2 stores the latest timer value (timer value of the last received frame) for each transmission bereavement (by node address), and the timer value check unit 121 checks the transmission bereavement timer value from the source address in the received frame. The timer value of the corresponding node in the table 122 is read and compared with the timer value 183 in the frame.

In this comparison, if the timer value 183 in the received frame is larger than the timer value in the table, that frame is a new frame received for the first time in this node, so it is identified as a valid frame and transmitted by the table update unit 124. The timer value of the corresponding transmission source in the bereavement timer value table 122 is rewritten with the timer value in the received frame.

In the comparison operation in the timer value checking section 121, if the timer value in the received frame is equal to or smaller than the timer value in the transmission bereavement timer value table 122,
The received frame is discarded as a previously received frame and is not transmitted to other nodes.

[Example] A configuration diagram of an embodiment of the present invention is shown in FIG. 2 (al).

Figure 2 (29 in al is a transmitting circuit, 21 is a receiving circuit, 22
is a timer, 23 is a transmission control section, 24 is a reception control section, 25
2 is a network communication processing unit; 26 is a table control unit;
Reference numeral 7 represents a memory in which a source-specific timer value table 271 is stored, and 28 represents a higher-level device. Timer 22 can be used as either a hard timer or a soft timer.
Hours 2 minutes 1 second.

It has a function to measure and output time in milliseconds.

The timer value table 271 for each source in the memory 27 has written therein the timer values of the latest received frame for all node addresses other than the own node address, and all are set to O'' in the initial state.

Figures 3 and 3 show the transmission control flow and reception control flow when a plurality of nodes N1 to N6 with the node configurations shown in Figure 2 (al) configure a mesh network as shown in Figure 2 (bl). This will be explained using Figure 4.

The transmission operation will be explained using the transmission control flow diagram of the embodiment shown in FIG.

Node N1 of the mensch network shown in Figure 2 (bl)
A case will be explained in which a broadcast frame is transmitted from a station. When there is a transmission request from the host device 28 via the network communication processing unit 25, the transmission flow starts, the transmission control unit 23 starts creating a transmission frame, and in step 31.32, the transmission frame is Sender (SN
) section address. Next, the timer 22 is read and the frame timer value 183 (see FIG. 1 (bl)) is set.

Next, in step 33, the transmission data given from the host device, Fe2 (frame check sequence), and F (flag) are added to the end of this timer value, as in the past, to create the broadcast frame shown in Fig. 1 fbl. Then, frames with the same content are transmitted from the transmitting circuits 29 (only one is shown in FIG. 2) corresponding to all the connected lines Nl and N2.

The reception operation will be explained using the reception control flow diagram of the embodiment shown in FIG.

Regarding the common control flow that all nodes have, when a frame is received from the receiving circuit 21 from the line, the reception control unit 24 checks Fe2 of the received frame. Fe2 is performed using a known CRC (cyclic redundancy check) (FIG. 4, 42), and if an error is detected, the received frame is discarded and the process ends.

If no error is detected by the CRC, the source address in the frame is detected to determine whether it matches the own node address, and if it is determined that the own node is the source, the received frame is discarded (the same 43).

If the own node is not the source, the network communication processing unit 25 performs the following control.

First, the timer value 183 in the frame (Fig. 1 (bl
) is larger than the corresponding timer value in the source-specific timer value table 271 (FIG. 444). At this time, the SN of the frame is determined from the timer value table 271 by transmission source.
The timer value in the column of the source node address specified by the unit is read out and compared.

If the timer value of the received frame is equal to or less than the timer value of the table, the received frame is discarded, and if the timer value of the received frame is greater than the timer value of the table, the table is updated next and the current received frame is The timer value of the received frame is written into the source-specific timer value table 271 (45).

Next, it is determined whether the DN part (destination address) of the frame matches the address of the own node (46),
If it matches the own node, the data part (DA
TA) to the higher-level device (47), extracts the content up to the timer value of the received frame, creates and appends Fe2 to the extracted content, and sets the terminal F (flag) (48) ). Next, the frame after extracting the data part is transmitted to all lines other than the line on which it was received (49). In the above step of determining the DN part of the frame, if the transmission destination is another node, the received frame is held as is and
8 to all other lines, and the transmission is executed by instructing the transmission control unit 23 from the network communication processing unit 25.

In step 46 above, the DN section (destination address)
If the received frame is not addressed to the own node when checked, the received frame is sent as is to all lines (50).

In the present invention, it is possible to perform broadcast communication to all nodes, and at the same time, individual communication is also possible. In addition, the timers 22 provided in each node only need to continue counting time independently and do not need to be synchronized with each other, so those with a simple configuration can be used.

[Effects of the Invention] According to the present invention, regardless of the shape of the mesh network, broadcast communication can be performed in the minimum time without causing frame stagnation, and network changes (addition/deletion of nodes) can be easily performed. The communication efficiency of the mesh network can be improved.

[Brief explanation of the drawing]

Fig. 1 fa) is a basic configuration diagram of the node of the present invention;
bl is a diagram showing the broadcast frame format of the present invention, FIG. 2 is a diagram showing the configuration of an embodiment of the present invention, FIG. Control flow diagram, FIG. 4 is a reception control flow diagram of the embodiment,
FIG. 5 is an explanatory diagram of a communication system of a conventional mesh network. In Fig. 1 fal, 10: Node (communication device) 11: Transmitting unit 12: Receiving unit 13: Network control unit 111: Timer 112: Transmission frame creation unit 121: Timer value checking unit 122: Source side timer value table 123 ; Sender check unit 124: Table update unit

Claims (1)

[Claims] A plurality of nodes are connected in a mesh shape through communication lines,
In a broadcast communication system in a mesh network, each node transmits communication frames transmitted from other nodes to other nodes.
) is equipped with a timer (111) that displays the time including the year, month, and day, and the information section (111) of the communication frame transmitted from its own node.
8), the destination address (181) and the source address (1
82) and the timer value (183) at that time, and the receiving unit (12) of each node transmits the timer value (183) in the received communication frame to the timer value checking unit (121).
The communication frame is compared with the timer value stored in the timer value table for each source (122), and depending on the result, it is determined whether to discard the received communication frame or to transmit it to another node. Broadcast communication method in mesh network.