JPS63267040A - Data transmission method in loop network and interface used for network - Google Patents

Abstract

PURPOSE:To easily delete a loop signal at an accurate timing from above a loop by controlling the timing of a start point and an end point interrupting relaying with using only a frame transmitting timing and a signal receiving timing in a self station. CONSTITUTION:Plural interfaces 9 are connected with adjacent interfaces 9 in a unilateral transmission line 10. In respective interface 9, the start point of a relaying interruption period 5 is set to the start point 6 of frame transmission. In a period when the self-station continues the transmission of the frame, relaying is interrupted and in a period 2 when received signals continues while the self-station transmits the frame, relaying is interrupted. If the self-station did not receive the signal while the self-station transmits the frame, relaying is interrupted until the end point when the signal which has been initially received after the transmission termination is terminated. Thus, the received signal can be deleted from above the loop and the frame or a part of it is prevented from initially circling.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a data transmission method in an information communication system and an interface used therefor, and particularly relates to a loop (
The present invention relates to a data transmission method using a ring-shaped network and an interface used therefor. [Background Art] Data transmission formats in information communication systems, especially local area network (LAN) systems, which have recently been developed, are classified into path format, loop format, and star format, depending on the configuration of the network. It ends with what you do. Here, in the path format, a plurality of interfaces are provided on one linear transmission path, and a terminal device is arranged for each interface. In addition, in the loop type, the transmission line is formed into a ring, a plurality of interfaces are provided, and a terminal device is arranged for each interface. Furthermore, the star format focuses on the exchange device,
Terminal devices are arranged in a star shape. When attempting to realize the various formats mentioned above with optical 7-fibers, path-type or star-type network systems must be bidirectional transmission paths, and for this reason, it is necessary to use bidirectional transmission paths between individual interfaces or exchange devices. One bidirectional optical 7 fiber or two unidirectional optical 7T fibers must be prepared for the connection between the terminal device and the interface device.In either case, the optical transmitter and optical receiver must be connected to the Twice the number of units is required. On the other hand, in a loop type network, it is possible to construct the network by simply providing a unidirectional transmission path between the interfaces. Therefore, even if optical 7 fibers are used in a loop-type network, the number of optical transmitters and receivers only needs to be the same as the number of interfaces. Therefore, it would be better if a path-type or star-type network could be converted to a loop-type network. It becomes possible to easily construct a network system. In order to convert a path-type network to a loop-type network, it is necessary to prepare a mechanism that allows frames sent by one interface to the transmission path to be received by all interfaces within a certain amount of time. To do this, each interface requires a relay means that retransmits frames received by the local station in their original form.However, unconditionally, the frames received by the local station are There is a problem with transmitting the frame again in the form of an *insect.In other words, if the frame received by one station is unconditionally transmitted again in the *insect form, the frame transmitted by one station will be relayed by all stations, so it will remain forever. The loop continues, making it impossible to transmit subsequent frames.Therefore, the conventionally used method is to
As shown in the figure, when a station transmits a frame,
A means is provided to interrupt the relay inside the interface at timing 4, which is delayed by the delay time 3 at timing 2* when the frame of the own station goes around the loop and is received with respect to transmission timing 1. . By doing this, the signal can be deleted from the loop when the frame transmitted by the local station has completed one cycle.

Problem 1 to be Solved by the Invention When erasing a signal that has gone around the loop using the conventional method described above, it is necessary to accurately grasp the time that the signal takes to go around the loop. However, this time is determined by the loop configuration, that is, the length of the transmission path, the number of interfaces (the number of relay means), the size of the delay time inside the relay means, etc., so if the loop configuration is changed, the delay time 3. It is necessary to perform the measurement again and change the timing at which the relay is interrupted.
Even if the relay is interrupted exactly at the delay time 3, if the delay time 3 changes for some reason, the timing will need to be changed as well. Normally, even if the delay time or the timing of interrupting relay changes slightly, the timing of interrupting relay is the timing of receiving the frame transmitted by the own station, so that the frame transmitted by the own station is reliably erased. If a time larger than 2 is set, or if the time is set too long, the problem arises that there is a high possibility that frames issued by other stations will also be erased. E.Means for Solving Problems and Their Effects It is an object of the present invention to provide a loop-type data transmission method that solves the problems of the conventional methods described above, and an interface used therefor. As shown in the operation timing in Figure 1, relaying is interrupted using only the frame transmission timing and signal reception timing at the own station, without depending on the network configuration called "delay time" and using unstable time. Control the timing of start and end points. That is, the start (starting point) of the relay interruption period 5 is the time point 6 when the own station starts transmitting frames, and during the period 1 during which the own station continues transmitting frames, the relay interruption continues. Furthermore, even during period 2, when a signal received while the own station is transmitting a frame continues, the relay is interrupted. Furthermore, if your station does not receive a signal while transmitting a frame,
The point at which the first signal received after transmission ends (end point)
By erasing the received signal from the loop in the manner of 0 or more, it is possible to prevent the frame or part of it from continuing to circulate on the loop forever. That is, according to the present invention, in a data transmission method using a loop-type network in which a received frame is transmitted to another station by relaying the received signal, the relay is started from the time when the local station starts transmitting a new frame. When the station stopped transmitting the frame, the station continued transmitting the frame, the signal received while the station continued transmitting the frame continued, or the station did not receive the signal while the station continued transmitting the frame. There is provided a data transmission method in a loop network characterized in that the relay is interrupted until the first signal received after the transmission of the frame is finished, and then the relay is resumed. An interface used in a loop-type data transmission system configured by connecting multiple interfaces in a loop using a transmission line to achieve the following: (a) A received signal from a reception transmission line is used for transmission. (b) means for detecting the received signal from the receiving transmission path; (a) transmitting a new transmission signal to the transmitting transmission path via the interface; (d) depending on the means for detecting the received signal and the means for detecting the transmission, from the receiving transmission path when the interface starts transmitting the new transmitted signal; The interface starts to interrupt relaying of the received signal to the transmission transmission path, and while the interface continues to transmit the new transmission signal, the signal received while the interface continues to transmit the new transmission signal continues ( and if the interface does not receive a signal while continuing to transmit the new transmission signal, it continues to interrupt relaying until the first signal received after the transmission of the new transmission signal ends, and then Provided is a loop network interface characterized by comprising means for controlling the relay means to restart relaying. [Example] Next, an example of the data transmission method according to the present invention and an interface used therein is provided. Fig. 3 shows an example of the configuration of a loop-type network to which the present invention is applied.In Fig. 3, a plurality of interfaces 9a,
Each of 9b, 9c... is a unidirectional transmission line of 10 m, 1
Adjacent interface 9b with 0b, 10a...
, 9c, '9d... Figure 4 shows the interfaces 9m, 9bs, 9c, etc. in Figure 3.
FIG. 2 is a block diagram structurally showing the internal configuration of one of the devices. In FIG. 4, when the switch section 11 is ON, the transmission line 20
It outputs the signal 13 from the receiving section 12 connected to the transmitting section 14 as the signal 15, and does not output it when it is OFF (the transmission line 20 is hereinafter referred to as a receiving transmission line). 0N10FF of the switch section 11 is a switch. It is controlled by a switch control signal 1f from the control section 16. A reception status signal 18 from the reception s12 and a transmission status signal 19 from the transmission unit 14 are input to the switch control unit 16. Reception status signal 1
8 is a signal that is output only while the receiving unit 12 is detecting the received signal from the transmission path 20, that is, only in the darkness where the received signal is present. In addition, the transmission status signal 19 is the transmission state signal 11S1.
4 is a transmission path 2 connected to the transmission unit 14 for transmitting frames of its own station.
1 (hereinafter referred to as the transmission line for transmission), and is always output only from the leap that has already transmitted its own frame. In FIG. 4, the operation of the switch control section 16 is as follows. However, in the initial state, it is assumed that the transmitting unit 14 is not transmitting its own frame, that is, the transmitting state signal 19 is not output. (1) In the initial state, the switch control section 16 turns on the switch section 11 (. (2) When the transmission state signal 19 is output to the switch control section 16, regardless of the state of the reception state signal 18. Keep the switch WSII OFF. (3) If the transmission status signal 19 is interrupted, keep the switch section 11 OFF. (4) When the transmission status signal 19 is not output, turn off the reception status signal. 18 is not output (that is, at the falling edge of the reception status signal 18, the switch control section 16 turns on the switch section 11 and maintains that state. By the switch control section 16 performing the above operations, the switch control section 16 automatically The station interrupts the relay of all signals received while transmitting a frame, and deletes the first continuous signal received from the loop when transmission ends.As a result, the delay time of the received signal from the transmitted signal is Regardless, the frame of the own station that has completed one cycle is deleted from the loop. Fig. 5 is a diagram showing an embodiment of an interface circuit that realizes the schematic block diagram of Fig. 4. Fig. 5
In the interface having the configuration shown in the figure, the signal from the reception transmission line 20 is outputted to the reception signal line 33 by the receiver 23. This signal is demodulated by the demodulation section 24 and becomes an output 41 to a communication control section (not shown) of the interface. The signal on the output signal line 33 of the receiver 23 also serves as an input to the received signal detection section 25.
A signal of logic level 1 is output to the signal line 34 only when a signal exists on the signal line 34, and a signal of logic level 0 is output at other times. Note that the combination of the receiver 23, the demodulator 24, and the received signal detector 25 corresponds to the receiver 12 in FIG. 4. The signal on the signal line 34 (18 in FIG. 41) has its logic level inverted by the inverter 26 and is input to the S input of the RS7 lip 70 via the signal line 35. On the other hand, a signal at an input 42 from a communication control section (not shown) of the interface is modulated by a modulation section 31 and output to a signal line 38. This signal line 38 serves as an input to the transmission signal detection section 30. Similar to the received signal detection section 25, the transmission signal detection section 30 detects the signal line 3 only when a signal exists on the signal line 38.
A signal of logic level 1 is output to B, and a signal of logic level 0 is output at other times. The R57 lip 70 tab 27 is the input signal line 3 on the R input side.
The leap whose logic level is 1 is always reset regardless of the state of the signal on the S input side.
It is set when the logic level of the input signal line 35 changes from 0 to 1, that is, at the rising edge of the signal on the input signal line 35. The output signal line 37 from the output Q of the RS7 rip 70 rip 2
When the S7 lip 70 knob 27 is in the set state, a logic level 1 signal is applied, and when it is in the reset state, a logic level 0 signal is applied. The gate circuit 28 is connected to the signal line 3
The input signal from the signal A133 (13 in FIG. 4) is output to the signal line 39 only while the logic level of the input signal from the signal A133 (13 in FIG. 4) is 1. Also, the OR circuit 29 outputs the signal #1
The logical sum of the signals on signal line 38 and signal line 39 is output to signal line 40 and input to transmitter 32 . transmitter 3
2 outputs this signal to the transmission line 21 for transmission. Note that the combination of the transmitter 32, the modulation section 31, the transmission signal detection section 30, and the OR circuit 29 corresponds to the transmission section 14 in FIG. The combination of the inverter 26 and the RS7 lip 70 and the switch controller 16 in FIG. 4 corresponds to the switch controller 16, and the gate circuit 28 corresponds to the switch controller 11. As is clear from the above description, in the interface in the configuration shown in FIG. Reset. R
When the 57 lip 70 knob 27 is reset, the logic level of one input of the gate circuit 28 becomes 0, and the signal line 3
The received signal #3 is not output as signal #139. After that, when the received signal is input from the reception transmission line 20 and appears on the signal line 33, the signal detection unit 25 outputs a signal of logic level 1 to the signal line 34. Next, when this received signal ends and disappears from the signal line 33,
The signal detection unit 25 changes the logic level of the signal output to the signal line 34 from 1 to O. As a result, the input to the S input of the RS7 rip 70 rip 2f will range from logic level 0 to 1 &
l: Change. Therefore, the RS7 lip 70 bit 2f is set and outputs a logic level 1 signal to the signal line 3f. As a result, the gate circuit 28 outputs the received signal on the signal line 33 to the signal line 39. This signal passes through the OR circuit 29 and is output to the transmission line 21 by the transmitter 3z. [Effect of the Invention J As explained above, when a network with a bus-type protocol is constructed using the loop data transmission method according to the present invention, it is possible to easily transmit data without using delay timing as in the conventional method. Moreover, the one-cycle signal can be deleted from the loop with accurate timing. Therefore, not only is there no transmission failure caused by a frame transmitted by a certain station circulating on a loop, but there is also no problem of inadvertently erasing a loop transmitted by a station. In addition, in the data transmission method according to the present invention, frames received while transmitting frames of the local station are not relayed.
Collisions between 7 frames do not occur in principle, so the collision loss function can be omitted even in the protocol that detects collisions, and since collisions do not occur, highly efficient transmission is achieved with a simple configuration. can do.

[Brief explanation of drawings]

FIG. 1 is a timing chart showing the relationship between the transmission period, reception period, and relay interruption period in one interface in the data transmission method according to the present invention, and FIG. 2 is a timing chart in the conventional data transmission method,
Fig. m3 is a diagram showing a loop-type transmission network to which the present invention is applied, Fig. 4 is a block diagram schematically showing the configuration of an interface that realizes the data transmission method according to the present invention, and Fig. 5 5 is a diagram showing an embodiment of the interface shown in FIG. 4. FIG. 1... Frame transmission timing of the own station, 2... Timing at which the frame transmitted by the own station is received, 3... Time for the signal to go around the loop, 4... Relay interruption timing in the conventional method, 5... Relay interruption timing according to the present invention, 6... Time to start transmitting frames of own station, 9a to 9r... Interface, 10a to 10f... One-way transmission line, 11... Switch section, 12... Receiving section, 13... Received signal from the receiving section, 14... Transmitting section, 15... Relay signal to the transmitting section, 18... Switch control section, 17... Switch control Signal, 18... Reception status signal, 19... Transmission status signal, 2G, 21... One-way transmission path, 23... Receiver, 24... Demodulation section, 25... Reception signal detection section , 26...Intermeter, 27...RS7 lip 70 tube, 28...Gate circuit, 29...OR circuit, 30...Transmission signal detection section, 31...Modulation section 1 32 ...Transmitter, 33...Output signal line of receiver 23, 34...Output signal line of received signal detection @25, 35...Inverter 1
6 output signal line, 36... Output signal line of the transmission signal detection unit 30, 37... Output signal line of the RS7 lip 70 tube 27, 38... Output signal line of the modulation unit 31, 39... Output signal line 40 of gate circuit 28...OR
Output signal line of circuit 29. Inventor Oka 1) Hiroshi Saito Noritaka Akabane Hidetomo 1) Masatoshi

Claims (3)

[Claims] (1) In a data transmission method using a loop-type network that transmits received frames to other stations by relaying the received signal, the relay is interrupted from the point at which the local station starts transmitting a new frame, and While the station is continuing to transmit the frame, while the signal received while the station is continuing to transmit the frame continues, or when the station does not receive a signal while continuing to transmit the frame, the frame The relay will continue to be interrupted until the first signal received after the transmission is completed, and
A data transmission method in a loop network, characterized in that the relay is then restarted. (2) An interface used in a loop-type data transmission system configured by connecting a plurality of interfaces in a loop using transmission paths, the interface comprising: (a) sending a received signal from a reception transmission path to a transmission transmission path; (b) means for detecting the received signal from the receiving transmission path; and (c) detecting that a new transmission signal has been transmitted to the transmitting transmission path via the interface. (d) a received signal from the receiving transmission path when the interface starts transmitting the new transmitted signal, depending on the means for detecting the received signal and the means for detecting transmission; start interrupting relaying to the transmission line for transmission,
While the interface continues to transmit the new transmission signal, while the interface receives a signal while the interface continues to transmit the new transmission signal, and while the interface continues to transmit the new transmission signal, It is characterized by comprising means for controlling the relaying means so that when the overconfidence signal is not received, the relaying continues to be interrupted until the first received signal is terminated after the transmission of the new overconfidence signal is completed, and then the relaying is resumed. An interface for loop networks. (3) The means for controlling the relay means comprises a flip-flop responsive to the means for detecting the received signal and the means for detecting transmission, and a gate circuit responsive to the output of the flip-flop. The interface according to claim 2.