JPS59196645A - Data communication system - Google Patents

Abstract

PURPOSE:To lay a transmission line with two-system system in which data do not collide with each other by connecting the transmission line in a loop constitution to constitute a data communication network, and giving priority on a data reached a port first from two ports of a data processor. CONSTITUTION:In transmitting a data from the data processor 2, the data from a data processing section 15 is converted into a signal form on a transmission line at a data form converting section 16 and transmitted respectively to transmission lines 1', 2' via OR logical elements 11, 12 and drivers 6, 8. The data reaching the transmission lines 1', 2' is inputted respectively to one input of AND logical elements 9, 10 and a first arrival priority deciding section 14 via receivers 5, 7 at the receiving when the data is reached earlier from the data to the transmission line 1'. The first arrival priority deciding section 14 decides the first arrival signal between the data from the receivers 5, 7, a first arrival signal is outputted to a prescribed signal line (18 in this case), and the passing/inversion of both the data are controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a communication system for a data communication network in which a plurality of data processing devices are connected by transmission paths, and more specifically, two transmission paths are provided between each data processing device. The present invention aims to improve the reliability of the data communication network against failures in the transmission path at low cost by enabling the same operation as if two data transmission paths were installed between each data processing device. Regarding the data communication method implemented.

As a means of improving reliability against failures in the transmission lines of data communication networks, two transmission lines are installed for the data transmission route, and normally one of the transmission lines is used, and when a failure occurs in that system. In this case, the other system was used. The method for improving the reliability against transmission line failures requires the provision of two transmission lines, which has the drawback of increasing costs.

An object of the present invention is to provide a data communication system that can improve reliability against transmission line failures at a lower cost than conventional data communication networks formed by connecting a plurality of data processing devices via transmission lines. There is a particular thing.

A data communication network is made up of a plurality of data processing devices and transmission paths connecting them.

Various methods for connecting transmission paths between data processing devices constituting a data communication network have been proposed. In the present invention, in order to reduce the cost of installing a transmission line, each data processing device is equipped with two sets of boats, and one boat has two data processing units equipped with means for transmitting data received to the other boat. A connection method is adopted in which the data processing devices are sequentially connected by connecting one port of each device with one transmission path.

In conventional data communication networks, when a failure occurs that disconnects the transmission path between adjacent data processing devices, the data communication network is cut off at that point and the data communication network is disconnected between the data processing devices that formed the R4 data network. The data transmission path will be cut off there.

As a means of improving reliability in response to failures in which the transmission line is disconnected, a method of installing two transmission lines has been proposed and implemented in the past.

The present invention provides a means for improving reliability equivalent to installing two transmission lines, in which the transmission lines are connected in a loop configuration, and the data processing devices forming the data communication network transmit data in two directions of the loop. The first feature is as follows.

However, if the method described above is simply used, the data sent from a certain data processing device that makes up the data network will collide somewhere in the loop, making it impossible to perform normal data communication. . Therefore, in order to avoid the above-mentioned data collision, a second method is provided in which the data processing device has a means of giving priority to the data of the boat whose data arrived first among the two boats and transmitting the data to the other boat. Features. By having this means, a data processing device that receives data will always give priority to data on one of the transmission paths connected to the data processing device, and data collisions will not necessarily occur. This occurs in only one transmission path among the transmission paths that make up the communication network. However, when this collision occurs, the data processing devices connected to both ends of the transmission line have already decided to give priority to the one that is not on the transmission line among the two sets of boats owned by the data processing device. Therefore, the above 2
This can be done so that it does not affect the data reception operations of other users.

With such a configuration, it is possible to provide two data transmission paths without installing two transmission paths.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a system diagram showing the connection status of a data communication network to which the method of the present invention is applied.
Therefore, this is an example of forming a data communication network.

Note that in implementation, the number of data processing devices is arbitrary.

In the figure, 1.2 and 3.4 are data processing devices,
11, 21, 3/, and 4/ are transmission lines connecting these devices.

FIG. 2 shows the details of the data processing device 2 shown in FIG. 1. Each data processing device has the same configuration as this data processing device 2.

In the figure, numerals 5 and 6 each represent a receiver and a driver that constitute one of the two ports of the data processing device, and 7.8 a receiver and a driver that constitute the other boat. 9,
1o is an AND logic element, 11, 12, and 13 are OR, i-filled elements. Reference numeral 14 denotes a first-come-first-served priority determination unit that determines which of the receivers 5.7 detects data first. 15 is a data processing unit;
16゜17 converts the signal format on the transmission path and the signal format in the data processing unit; 16 converts the signal format in the data processing unit to the signal format on the transmission path; 17c converts the signal format on the transmission path to the data processing unit This is a data format conversion unit that converts the signal format into the signal format.

In FIG. 1, when data is transmitted from the data processing device 2, the data is sent to both transmission paths 11 and 21. The data sent to the transmission path 1' is relayed by the data processing device 1, transmitted to the transmission path 4', and further transmitted to the data processing device 4. On the other hand, the data sent to the transmission path 2' is relayed by the data processing device 3, transmitted to the transmission path 3', and is also transmitted to the data processing device 4. As a result, the data processing device 4
, 4 / receive data almost simultaneously, but data that arrives earlier is given priority. If data on the transmission path 3' side is detected early, the data processing device 4 will detect the data on the transmission path 3' side.
The side data is sent to the transmission path 4'. Data from data processing devices 1 and 4 collide with each other on transmission path 4', but data processing devices 1 and 4 are connected to transmission paths 1' and 3, respectively.
It has already been determined that the data from ' has priority, so there is no problem with the operation.

Here, even if the transmission path 1' is disconnected, the data from the data processing device 2 is first transmitted to the data processing device 3, then from the data processing devices 3 to 4, and then from the data processing device 4 to 1. Therefore, data from the data processing device 2 can be transmitted to all data processing devices within the data communication network without any problem.

Next, the operation of the data processing apparatus will be explained with reference to FIG.

When transmitting data from the data processing device 2, the data from the data processing unit 15 is converted into a signal format on the transmission path by the data format conversion unit 16, and then sent to the transmission path 1' via the OR logic element 11 and driver 6. is sent to and OR
It is also sent to the transmission line 2' via the logic element 12 and driver 8.

When data processing device 2 receives data, if there is no fault in the transmission path, data arrives from both transmission paths 1 and 21, but here, data on transmission path 1' arrives earlier than transmission path 2'. Let me explain the case.

The data arriving at the transmission path 1' is inputted via the receiver 5 to the first-come-first-served priority determination unit 14 and one input terminal of the AND logic element 9. Further, the data that has reached the transmission line 2' is inputted via the receiver 7 to the first-come-first-served priority determining section 14 and one input terminal of the AND logic element 1o.

First-come-first-served priority determination unit 14 receives data from receivers 5 and 7, and if data from receiver 5 arrives first, it sends a first-arrival signal to signal line 18, and if data from receiver 7 arrives first, it sends a first-arrival signal to signal line 19. Appear. In this case, since the data from receiver 5 is first-arrived, the first-arrived signal is output to signal line 18.

The data from receiver 5 therefore appears at the output of AND logic element 9. The output data of AND logic element 9 is O
The signal reaches the data processing section 15 via the R logic element 13 and the data format converter 17, and is transmitted via the OR logic element 12 and the driver 8 to the transmission line 2'. Data from receiver 7 is blocked by AND logic element 10. By the above-described operation, the data processing device can give priority to the data that arrived first among the data from the two boats, and can repeatedly transmit the data from the boat that arrived first to the other boat.

As explained in detail above, the data communication system according to the present invention allows data transmission paths between any two data processing devices in a data communication network to be connected without installing two transmission lines constituting the data communication network. can be made into two systems, and reliability against transmission path failures of the data network can be improved with a simple fk configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a data communication network to which a communication method according to the present invention is applied, and FIG. 2 is a circuit diagram showing an embodiment of a data processing device. 1.2, 3.4...Data processing device 1'+2'+3'64'...Transmission line 5.7...
Receiver 6.8...Driver 9.10...AN
D logic element 11.12. I: (...OR logic element 16.17...
・Data format conversion unit 14...First-come-first-served destination determination unit 15...Data processing unit Patent applicant NEC Corporation agent Patent attorney Hisashi I) Ro

Claims (1)

[Claims] For data communication with other data processing devices, two sets of data communication boats are provided with a receiver and a driver, and a first-come-first-served priority determination unit that determines first-come-first-served priority for data arriving at the two sets of data communication boats. , a data processing section, and a data format conversion section that mutually converts the data signal format on the transmission path and the data signal format of the data processing section (a plurality of processing devices are connected to two When a data communication boat is connected to a data communication boat of a different data processing device through a data transmission line to form a loop, and each data processing device sends data to another data processing device, the data The data processing section of the processing device sends data to the drivers of two data communication ports via the data format conversion section, and when receiving data from another data processing device, the first of the two data communication ports 1. A data communication system, characterized in that data from a receiver of a data communication boat that has received data is transmitted to a driver of the other data communication boat according to an output of the first-come, first-served priority determining section.