JPS59122152A - Local network communication system - Google Patents

Abstract

PURPOSE:To attain the processing of a lot of data in high speed by constituting a communication loop by plural loops. CONSTITUTION:Communication nodes A, B... are accommodated in n-line of loops and access to the loop in common. The communication node discriminates only a data addressed to the own node and branched. Then, the other data are passed through without any change. When the communication node starts transmission, a token circulating on the plural loops is supervised and the loop receiving the token at first is selected. The token is fetched once to the node. When the transmission from the said node is finished, the token is transmitted onto the loop. The waiting time of the node is reduced and the efficiency of communication is improved by providing the simplicity of the token passing system and providing plural loops.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a local φ network communication system, and in particular to a token passing system.
) regarding a loop communication method using

In recent years, local networks that interconnect computers and data terminal equipment located in the same building, factory, or site have attracted attention as a basic means of promoting office automation and factory automation, and various methods are being used. has been proposed and put into practical use. One of the most prominent methods is token passing (token passing) as a net-to-external access control method for loop networks.
This is a method that adopts Token Passjng).

FIGS. 1, 2, and 3 are diagrams showing the loop network configuration of this system and the basic configuration of each communication notebook, as well as its operating principle.

FIG. 1 shows communication nodes A that are distant from each other.

B, C, D, . . . are accommodated in one loop, and show a network configuration in which the loops are commonly accessed. Each communication node L I U (Loop Inter
As shown in Figure 2, the faceUnit) is a receiver RX that receives signals arriving from an adjacent front communication node via a loop cable, and identifies and branches only the communication information addressed to its own node from the received signal and receives it. A branch circuit JJ1 (token reception detection circuit TKNCHK that extracts and detects a communication permission signal (hereinafter referred to as a token), which will be described later) from the P1 received signal, has the function of sending data RD to the node terminal and passing other signals as is. , The transmission data SD from the own node terminal is included in the communication information string passing through the node.
It consists of an insertion circuit INS that receives and inserts the signal, and a transmitter TX that sends a signal to the cable to an adjacent downstream communication node.

FIG. 3 is a diagram for explaining the operating principle of the conventional loop communication method using token passing. In the figure, for the sake of simplicity, three nodes A, B, and C are taken as an example, and the temporal changes in the signal I received from the preceding node and the signal O transmitted to the succeeding node are depicted. ing. In the figure, the shaded signal TKN indicates a token used for control for each communication node to access the loop. Usually one token circulates on the loop network, and the node that captures it has the right to access the loop and start communication. In other words, the token is a communication permission signal that grants communication rights to a node on the loop that can supplement the token.

In Figure 3, node A receives a token from the preceding node and acquires the right to communicate, so node A sends a message A addressed to another node to the loop, and after completing the loop, sends the token to succeeding node B. Retransmission: Node B receives the token from the preceding node A, and when it acquires the communication right, sends a message B addressed to another node from node B in a loop, and after completion, it resends the talk to the succeeding node FC. A series of actions are shown.

As can be seen from the above explanation, although the token passing method has a feature of a very simple system configuration, it has the following drawbacks.

The first drawback (Ma) This method can be said to be extremely advantageous when accommodating medium- to low-speed data terminals in a node, but when accommodating high-speed data terminals, image terminals, or a large number of voice information terminals, etc. In this case, all i6 messages are transmitted in a single loop, which causes a significant increase in loop speed, and there is a certain upper limit in terms of implementation.

The second drawback is that a loop failure will bring down the entire system, so the loop is normally set to
It is necessary to have a redundant configuration with a standby system.

An object of the present invention is to provide a highly reliable local network communication method that can process large amounts of high-speed data while maintaining the simplicity of the system configuration of the loop communication method using token passing. .

The present invention provides a loop communication method comprising a communication loop and a plurality of mutually distant communication cards that commonly access the communication loop, wherein the communication loop is composed of a plurality of loops, and Each communication node includes a transmitting means for communicating with one of the plurality of loops, a means for receiving a communication permission signal in each of the loops, and a communication node selected from among the plurality of loops according to the reception result of the communication permission signal. communication(
A means for selecting a loop to be used, a means for temporarily stopping retransmission of a communication permission signal to other communication nodes for a selected loop, and a means for immediately transmitting a communication permission signal to other communication nodes for a loop that is not selected. and a means for retransmitting to the node, and each communication node selects one of the loops received by the receiving means and transmits the communication permission signal on each of the loops using the transmitting means when the communication request is made. Immediately after the completion of the transmission, the communication permission signal of the loop is retransmitted to other communication nodes, and the communication permission signal is sent to the loop that is not selected, or for each loop when there is no communication request. By immediately retransmitting the communication permission signal to the other communication node via the corresponding loop, it is possible to process the large 1i-) and cylinder speed data, and the highly reliable local - Can provide network communication methods.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 is a configuration diagram of a local network according to an embodiment of the present invention, and FIG. 5 is a configuration diagram of a one-word node, and FIG. 5 is a diagram for explaining its operation.

FIG. 4 shows communication no-FAs that are spaced apart from each other.

B, C, D, ... are mutually accommodated in n loops,
The plurality of loops are jointly accessed. It shows a group.

Figure 5 shows each communication node LIU (Loop Interface Unit) in the case where the number of loops is two.
) shows the configuration of Each communication node has a receiver RX, which receives signals arriving from an adjacent preceding suitable node via two loop cables, , , RX, , and identifies only the communication information destined for its own node from the received signal of each loop.・Branch,
There is a branch circuit P with the function of passing other signals. , DRPl, a buffer memory circuit BM that temporarily stores the branch signal in a buffer memory and sends it out to the node terminal as received data RD in case the own node destination information arrives at the same time from each loop, a communication permission signal from the received signal. Token reception detection circuit TKNCHKo, TKNCI-iK, #t that extracts and detects (token)
--Selection circuit 5EL1 which obtains the output of the reception detection circuit and selects the loop to which the signal should be sent; a changeover switch circuit SW1 which thereby switches the output loop of the transmission data SD from the own node terminal η); output from the changeover switch circuit; an insertion circuit lN5o that receives the signal and inserts it into the loop communication path.
, INs□, a transmitter TXo, T which receives the insertion circuit output and sends a signal to the adjacent downstream node via a cable.
From X.

Next, to explain the operation of this system, when each communication node wants to start data transmission, it receives the transmission request signal R8, and as a result, the tokens circulating on each loop are sent to the above 1. - The loop that receives the token first is monitored by the token reception detection circuit and selected by the circuit SE.
Press L to select.

1.-kun of the selected loop is taken into the -J3 node, and after the data transmission from the node is completed, 14. Sent to the successor node. Unselected loop token I
(If there is no data transmission request, the token is immediately sent to the 1φ receiving node. When the loop to which the data should be sent is determined by the selection circuit, the changeover switch is set to a predetermined connection, and at the same time Self) - By outputting the transmission enable signal C8 to the upper terminal side, the transmission data 8D from the terminal is sent to the selected loop path.

FIG. 6 is a diagram showing an example of the operation of this system. The same figure (-) The same ball as the one in Figure 3, the three notes 'A, B.
, C as an example, it is shown how the signal ■ received from the preceding node and the signal O transmitted to the succeeding node change over time. The difference between Figure 6 and Figure 1 is that there are two loops in Figure 3.

The point is that the situations of +0 loop and +1 loose are depicted at the same time.

In Figure 6, node A receives the token from the previous nonid ≠
0. ≠1 from each loop, the +0 loose token is received first, the +0 loop is selected as the data transmission loop, it sends the message A, and after that, the token is sent to the node B. On the other hand, the received token from +1 loose is being sent to Node B immediately. As a result, node B receives the token from +1 loose first, so message B from node B
is sent by selecting the +1 loop. Thereafter, similar operations are performed at each node.

As can be seen from the above explanation, according to this method, by preparing n loops, the maximum limit of loop communication capacity can be set to n
It is a hot topic that it is possible to double the amount of data and process a large amount of data.The details are omitted, but due to the so-called ``traffic swarm effect'' in traffic theory, each node is If service standards such as transmission waiting time are held constant, it is possible to carry a much larger amount of data, it is fail-soft no matter which loop out of n loops becomes a failure, and It can be seen that it has the characteristics of being highly expandable, such as being able to determine the number of loops according to the required communication volume.

FIG. 7 and FIG. 8 are examples of application of the present invention. This example:
This is an attempt to do something equivalent to the previously described embodiments without increasing the number of physical loop cables, and the basic idea is the same as the present invention.

The conventional method shown in FIGS. 1 and 2 already mentioned, and FIG. 4.

In the method according to the embodiment of the present invention shown in FIG. 5, it was assumed that data transmission to a cable-to-wire cable, coaxial cable, or optical cable would be performed using a so-called baseband transmission method.

However, if a carrier wave modulation transmission method (for example, FM modulation method) is adopted, by preparing n carrier waves with different frequencies, it is possible to logically transmit n waves on a single twisted pair cable or coaxial cable. Loops can be constructed and the invention can be applied. Similarly, in the case of an optical loop transmission system, if an optical wavelength division multiplexing transmission system is adopted, by preparing n waves of light with different wavelengths, it is possible to logically construct n loops on a single optical cable. The invention is applicable.

The operation of this applied example method is as shown in FIG. Cable 1 is designated f in FIG. , fl carrier waves can be read as channels CHo and CHI, and in FIG. 8, the optical wavelength λ. , λ1 light channel CHO.

If read as CHl, it becomes exactly the same as the embodiment method of the present invention. Note that in FIG. 8, S and M represent an optical demultiplexer and an optical multiplexer, which are well known to those skilled in the art, and detailed explanations thereof will be omitted here.

As explained above, the present invention prepares N loops,
By applying a loop access method using token passing to this, a highly reliable local network communication method that can process large amounts of high-speed data can be realized.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a loop network according to a conventional method. FIG. 2 is a configuration diagram of the communication node in FIG. 1. FIG. 3 is an explanatory diagram of the operation of the methods shown in FIGS. 1 and 2. FIG. 4 is a diagram showing the configuration of the loop network according to the embodiment of the present invention. FIG. 5 is a configuration diagram of the communication node in FIG. 4. FIG. 6 is an explanatory diagram of 1jf) 1 of the method shown in FIGS. 4 and 5. The seventh tooth is a communication notebook configuration diagram of the first application example method of the present invention. 1. FIG. 8 is a communication node configuration diagram of the second application example system of the present invention. A, B, 'C, 1), ... communication node, 几X, I also X
. . "Xl-receiver, TX, TxO, TX, =-transmitter, ]) RP. DRP., DRP,...0 branch circuit, INS, INS., INS. 09. Push circuit, TKNCHK, TKNCHKo, T.K.
NCHK. -...Tanium/reception detection circuit, SEL...loop selection circuit, SW...loop selection switch, 0β. , Saisho,... Optical/Electric conversion circuit, Eloo, Elo,...
・Electrical/optical conversion circuit, RD... Reception data signal line, S
D: Transmission data signal line, R8: Transmission request signal line, C8: Transmission enable signal line. Seri Figure 3 Time → Figure 4 Figure 5 Scale D R5 (, S SD Kaoru Figure 6 r51 Time 0 Figure 7 RD R5C5SO Figure δ

Claims (1)

[Claims] In a loop communication system comprising a communication loop and a plurality of communication nodes separated from each other that commonly access the communication loop, the communication loop is composed of a plurality of loops, and each communication node has a plurality of communication nodes. A transmitting means for communicating with one of the loops, a receiving means for a communication permission signal in each of the loops, and a loop to be used for communication is selected from among the plurality of loops according to the reception result of the communication permission signal. means for temporarily suspending retransmission of the communication permission signal to other communication nodes for the selected loop; and means for immediately retransmitting the communication permission signal to other communication nodes for the unselected loop. When each communication node requests communication, it selects one of the loops from which the receiving means has received a communication permission signal on each of the loops, starts transmitting with the transmitting means, and immediately after the end of the transmission. The communication permission signal of the loop is retransmitted to other communication nodes, and if the communication permission signal is received by the receiving means for the unselected loop or for each loop when there is no communication request, the communication permission signal is immediately transmitted. A local network communication method characterized by retransmitting the information to other communication nodes via a corresponding loop.