JPH04108238A - Collision control system at terminal equipment of network - Google Patents

Abstract

PURPOSE:To prevent the reduction in the throughput in the entire network when collision takes place in a terminal equipment by interrupting the transmission of a transmission data once when a control section receives a collision signal and fetching a reception data into a reception data memory as a valid data. CONSTITUTION:When a controller 3 receives a collision signal and a reception data at its CIN terminal and DIN terminal, the transmission from a DOUT terminal is interrupted, and a data after a preamble among the data received by the DIN terminal is transferred to a reception data memory 2. Moreover, after the end of transfer, the frame check sequence of the reception data is checked to confirm to be a normal data and when the data is normal, it is confirmed that the reception data is addressed to its own terminal equipment T2. Thus, the terminal confirms the absence of a carrier on a transmission line L and even when collision is generated in the terminal equipment when the data is sent, no jam signal is sent, the reception data is made valid and fetched in the terminal equipment, then the reduction in the throughput is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a collision control method for a network forming a star-type LAN.

[Conventional technology]

In the IEEE802.3 standard regarding LAN (Local Area Network), the following processing is performed regarding collisions.

In other words, in the star-type LAN shown in FIG. 12, in which a plurality of terminals Tl to T3 and a line concentrator M are wired in a star shape, the line concentrator Medium access unit in device M (not shown)
A collision is detected, and a jam signal as a collision detection signal is sent to all terminals connected to the line concentrator M. The terminal TI-T3 that receives the jam signal interrupts the transmission process and waits for the next transmission timing. In this case, all data transmitted from the terminals Tl to T3 are discarded in consideration of waveform distortion due to collision, etc.

Therefore, there was a problem in that the throughput of the entire network was reduced.

In order to solve this problem, according to Japanese Patent Application No. 2-137778, a plurality of terminals T1 to T3 connected to the line concentrator M
Even if data to be sent simultaneously occurs and a collision is detected within the line concentrator M, only the data sent from one terminal will be valid and will be relayed without data loss, and at the timing of the next collision. We proposed a line concentrator M that can control transmission data from different terminals equally so that they are valid.

On the other hand, the terminal Tl-T3 side performs the following processing regarding the collision. First, if there is a carrier on the transmission path before transmitting data, it does not transmit and waits until the transmission path becomes free. Next, as shown in the communication sequence of FIG. 13, if, for example, the terminal T2 confirms that there is no carrier on the transmission path and transmits data, it receives data from another terminal Tl. In order to do this, the data being transmitted from terminal T2 is interrupted, followed by a jam signal to notify the entire network that a collision has occurred, and then the data is retransmitted after waiting for the next transmission timing (time T). Process.

In this case as well, all data transmitted from each terminal is discarded in consideration of waveform distortion due to collision.

[Problem to be solved by the invention]

However, when the terminal TI-T3 confirmed that there was no carrier on the transmission path and sent the data, the data that collided in the concentrator M but was determined to be valid,
For example, even if terminal T1 receives the data, if a collision occurs within terminal TI, the received data will be discarded, resulting in a problem that the throughput of the entire network will decrease.

The present invention has been made in view of the above points, and its purpose is to reduce the throughput of the entire network even if data is transmitted simultaneously from multiple terminals and a collision occurs within the terminals. The purpose of the present invention is to provide a collision control method for terminals in a network with no network.

[Means to solve the problem]

The collision control method at terminals of a network according to the present invention is a collision control method at network terminals forming a star-type LAN, and includes a transmission data memory for storing transmission data to be sent to other terminals; It includes a reception data memory that stores reception data from other terminals, and a control unit that performs data transmission and reception processing and interrupt processing when a collision signal indicating a collision between transmission data and reception data is input within the terminal. The controller is configured to, when receiving the collision signal during data transmission from its own terminal, temporarily interrupt the transmission of the transmitted data and import the received data into the received data memory as valid data. It is characterized by the following.

[Effect]

In the collision control method at the terminal of the network of the present invention, if a data collision signal occurs within the terminal while data is being transmitted from the terminal, the received data is not sent as a jam signal, and the received data is converted into a valid digital signal. I am trying to import it into the terminal as .

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. Second
The figure is a block diagram of a terminal T forming a network showing an embodiment of the present invention. The terminal T includes a transmitting circuit TS,
It consists of a receiving circuit TR, an interface board IB, and a terminal body TE.

A block diagram of interface port IB is shown in FIG. 1 is a transmission data memory, which stores transmission data to be sent to other terminals T.

Reference numeral 2 denotes a received data memory for storing data received from other terminals T. 3 is the controller,
It controls data transmission and reception, interrupts, etc.

4 is a collision detection circuit which outputs a collision signal to the CIN terminal of the controller 3 when the received data input to the received data input terminal DIN of the controller 3 and the transmitted data from the transmitted data output terminal DOUT of the controller 3 exist at the same time. It is something to do. 5 is a CPU that responds to the interrupt request signal from the DINT terminal of the controller 3 by returning an interrupt completion signal to the DACK terminal of the controller 3, and outputs a transmission request signal to the DRQ terminal of the controller 3. be. Controller 3 and CP
U5 constitutes a control section, and the control section performs data transmission/reception processing and interrupt processing when a collision signal indicating a collision within the terminal is input.

6 is a connector for connecting to the transmitting circuit TS and receiving circuit TR within the terminal T. 7 is clock signal C
8 is a system clock that generates K, and 8 is a frequency divider.

The operation of the interface board IB will be explained below using the timing chart shown in FIG. 3 and the communication sequence chart shown in FIG. 4. Main body T of terminal T2
A transmission request signal is sent to the controller 3 from the RQ terminal of the CPU 5 that received the data transmission request signal from E (data transmission request), and the controller 3, which receives the transmission request signal at the DRQ terminal, indicates that there is a carrier on the transmission path. After confirming that it is not
The data is read through the terminal and sent to the transmission path from the DOUT terminal. Simultaneously with this sending timing, the controller 3 sends the collision signal and received data to the CIN terminal and the DIN terminal, respectively.
If data is received at the terminal, that is, if data is also being sent from terminal T1, the transmission from the DOUT terminal is interrupted and the data after the preamble of the data received at the DIN terminal is stored in the reception data memory. Transfer to 2. After the transfer is completed, the frame check sequence of this received data is checked to confirm that it is normal data, and if it is normal, it is further confirmed that the received data is addressed to the own terminal T2. If it is addressed to own terminal T2, controller 3
interrupts the CPU5 from the DINT pin,
DA the interrupt completion signal from the ACK terminal of CPU5.
After receiving the received data at the CK terminal, the received data is transferred from the received data memory 2 to the terminal body TE (data reception notification). After the transfer is complete, confirm that there is no carrier on the transmission path,
Processing to retransmit the data in the transmission data memory 2 is performed.

Therefore, in the terminal of this embodiment, even if a collision occurs within the terminal when transmitting data after confirming that no carrier exists on the transmission path, the received data is valid without sending a jam signal. Since the data is downloaded to the terminal at the same time, there is no drop in throughput.

Next, the interface board IB shown in FIG.
FIG. 5 shows an example in which a star-type network is constructed by a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a terminal T having a line concentrating device M proposed in Japanese Patent Application No. 137778/1980. FIG. 6 shows a communication sequence chart of this embodiment. The line concentrator M includes a receiving circuit TR that receives data from a plurality of terminals T connected to the line concentrator M, a valid port determining circuit ED that determines and outputs valid data among the received data, and a valid port determining circuit ED. A relay processing circuit TP that reproduces a preamble of valid data output from and outputs it as relay data, an output port determination circuit OD that determines a boat to output the relay data, and output via the output port determination circuit OD. The transmission circuit TS includes a transmitting circuit TS for transmitting the relayed data.

In this line concentrator M, when transmission data is generated simultaneously from a plurality of terminals T connected to the line concentrator M, a valid determination logic circuit (not shown) in the valid port determination circuit ED transmits data via each port. Among the input data, it is determined whether the data is valid this time. Here, to determine which terminal is valid, refer to the previous example of determining valid data when data collides, and control the data evenly to avoid validating data from the same terminal all the time. I try to do that. The valid vote determining circuit ED outputs only the valid data determined by the valid determining logic circuit to the relay processing circuit TP, which performs processing such as reproducing the preamble and outputs it as relay data. Then, the relay data is output to the terminal selected by the output port determination circuit OD and which is not currently valid.

Therefore, according to this embodiment, when the terminal Tl-T3 confirms that no carrier exists on the transmission path and transmits data, a collision occurs within the line concentrator M shown in FIG. 5 above. Even if data that is considered valid is received and a collision occurs within the terminal, the received data will be taken in as valid data, so the received data will not be discarded, and the line concentrator M This prevents the throughput of the entire network from decreasing due to data collisions within terminals and data collisions within terminals.

In addition, as shown in FIG. 7, a star network consisting of a terminal T, a twisted pair conversion adapter TA connected to the terminal T and used to convert signals for the twisted pair line TP, and a line concentrator M is connected to the terminal T. An example of implementing the invention will be described next. FIG. 8 shows an example of the configuration of the twisted pair conversion adapter TA, and FIG. 9 shows an example of the configuration of the interface board IB below the terminal. The basic processing at the interface board IB is the same as that of the interface board IB shown in FIG. The collision signal generation circuit 11 detects a collision.
A collision notification signal is sent to the interface port IB of terminal T. In order to distinguish the collision notification signal from the SQE test signal generated from the SQE signal generation circuit 12, the collision notification signal is
It is transmitted with different waveforms as shown in the θ diagram. Therefore, the interface board IB is provided with a signal detection circuit 9 that separates the collision notification signal and the SQE test signal. In the interface board IB, the signal detection circuit 9 identifies the collision notification signal, and if a collision occurs, a High signal is sent to the CIN terminal of the controller 3 to notify the collision. FIG. 11 shows a timing chart on the interface board IB of FIG. 9.

In addition, 13 is a clock 14 that generates a clock signal, a loopback control circuit, 15 is a connector between terminal T,
16 is a connector for connecting the twisted pair wire TP.

〔Effect of the invention〕

As described above, according to the collision control method at the network terminal of the present invention, if a data collision signal occurs within the terminal during data transmission from the terminal, the jam signal is not sent and the data is received. Since the data is imported into the terminal as valid data, even if data is sent from multiple terminals at the same time and a collision occurs within the terminal, the throughput of the network as a whole will not drop. A collision control system was provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an interface port according to an embodiment of the present invention, FIG. 2 is a block diagram showing a terminal according to the above, FIG. 3 is a timing chart in the same, and FIG. FIG. 5 is a block diagram of another embodiment of the present invention. FIG. 6 is a communication sequence chart of the same. FIG. 7 is a system configuration diagram of the same. A block diagram of a twisted pair conversion adapter; FIG. 9 is a block diagram showing an interface port according to the above; FIG. 1O is a waveform diagram in the same; FIG.
1 is a configuration diagram of a star type LAN, and FIG. 13 is a communication sequence chart in a conventional example. l - Memory for sending data 2 - Memory for receiving data 3 - Controller 4 - Collision detection circuit 5 - CPU 6 - Connector 7 - System clock 8 - Frequency divider T Terminal 1B - Interface boat TE - Terminal body TS・Transmitter circuit TR, - receiver circuit Patent applicant Matsushita Electric Works Co., Ltd. agent Patent attorney Narji Sato (and one other person) Himasawa Miss? Figure 2 Figure 4 [1; 2 signal x + 24 houses 9. Detection, begging T Reiko on the 1st phone?

Claims (1)

[Claims] (1) A collision control method for terminals in a network that constitutes a star-type LAN, including a transmission data memory that stores transmission data sent to other terminals, and a reception data memory that stores reception data from other terminals. and a control section that performs data transmission/reception processing and interrupt processing when a collision signal indicating a collision between transmitted data and received data within the terminal is input, and the control section Collision at a network terminal characterized in that when the collision signal is received during data transmission, the transmission of the transmitted data is temporarily interrupted and the received data is taken into the received data memory as valid data. control method.