JPS6035854A - Data transmission system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency of the whole system by constituting plural data transmission devices connected to one transmission line annularly and the transmission line as a frequency dividing multiple system and circulating different tokens in respective frequencies. CONSTITUTION:N data transmission devices 1 are connected annularly through one transmission cable 3 and data processors 2 for transferring information are connected to respective devices 1. A token from a receiving cable 1a is inputted to a reception control circuit 12 through channels CHs 111-11n in a receiving interface IF circuit 11, and if the address in CHs does not coincide with the that of the office itself, the token is transmitted to a transmission cable 1b through the CHs 211-21n in an transmission IF circuit 21. When the address of the CHs coincides with that of the office itself, free tokens in respective CHs are sent from the circuit 12 to the processor 2 through a receiving circuit 13 and an external IF circuit 31 to be processed. When information is to be sent from the processor 2, an address and transmission information are added to the free token and the information is sent as a busy token to the cable 1b through a transmission circuit 23 and the circuits 22, 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a data processing system in which a plurality of data transmission devices of the same type are connected in a ring shape with a cable. In particular, when a transmission path is frequency-divided, tokens are circulated independently on each of a plurality of transmission paths, and when data transmission occurs between individual data processing devices, each data transmission device receives one of the circulating tokens. The present invention relates to a data transmission method in which a less used token is acquired and a destination address and transmission data are placed on it and transmitted.

[Description of prior art]

In general, in a data processing system in which multiple data transmission devices are connected in a ring, the data transmission device, which serves as a transmitting station, acquires a token that circulates on the ring, which is a transmission path. There is a way to load it and send it out to the ring. , it propagates on the ring at a constant speed, passing through successive data transmission devices in between.

Tokens are constantly circulating around the ring as long as an abnormal situation occurs. When a data transmission device with the other party's address is detected on the ring, this device recognizes from the address that the data is addressed to itself and takes in the data.

When the receiving data transmission device completes data addition,
The token is made free and released onto the ring, creating a state in which other arbitrary data transmission devices can use it for data transmission.

In this case, only one token circulates on the ring, and is used for data transmission by all data transmission devices making up the ring.

This method is easy to control the entire ring, but if the amount of data transmitted between data transmission devices on the ring increases, the transmitting station will have to wait until it can capture the free token. Transmission efficiency does not necessarily improve.

To this end, it is necessary to increase the clock speed of the entire ring to increase the token circulation speed and strive to improve transmission efficiency. Here too, there is a technical limit to increasing the clock speed, and it cannot be configured in a short-circuit manner.

In addition, in order to realize data transmission between multiple data transmission devices configured in a ring shape over a single cable,
While the number of data transmission devices is small, only one token is sufficient if the clock speed of the ring is satisfactory, but as the number of data transmission devices increases, the clock speed cannot keep up and free tokens are grabbed. The probability of formation of jin decreases, and the transmission efficiency decreases.

The present inventor has created multiple sets of states in which the system as a whole can transmit and receive at the same time by providing a plurality of transmission paths and using tokens circulating in the transmission paths by dividing the frequency of the data transmission device and the transmission path. The present invention was completed by focusing on the fact that the traffic of the entire ring can be increased.

[Purpose of the invention]

The present invention provides a data transmission method that can improve the transmission efficiency of the entire system by circulating tokens for each frequency-divided transmission path in a data transmission method between a plurality of data transmission devices installed in a ring shape. The purpose is to

[Features of the invention]

In the present invention, three or more data transmission devices are connected in a ring shape through one transmission path, and a token, which is the right to use the transmission path, is circulated through the transmission path, and each data transmission device uses the token. In a data transmission method configured to capture unused powerful tokens and transmit data to another data transmission device, the one transmission path is a frequency division multiplexed transmission path, The data processing system is configured to circulate different tokens for each frequency that is frequency division multiplexed, and each transmission device is configured to be able to select, capture, and use a token for each frequency. It is characterized by being able to improve the overall transmission efficiency.

[Explanation based on examples]

A device according to an embodiment of the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram showing a data processing system to which a data transmission apparatus according to an embodiment of the present invention is connected.

In this data processing system, n data transmission devices 1 are connected in a ring shape via one transmission cable, and a data processing device is connected to the data transmission device 1 to transfer information using the ring. 2 is added and configured.

In this system, even in times of high traffic due to an increase in transfer requests by the data processing device 2 and an increase in the amount of data, multiple devices are installed on the transmission path so that the processing of each data processing device 2 will not be delayed due to ring use. channels are provided so that information can be transferred between arbitrary sets of data processing devices 2 at the same time.

That is, a plurality of channels are provided by frequency-dividing the transmission path on each data transmission device 1 and ring, and one token is set on each channel,
It moves around the ring independently in the same direction. There is no particular weight between individual tokens, all of them are equal, and they always move around the ring at a constant speed. Further, the number of channels set by frequency division can take any value within the capability of the data transmission device 1 at the time of system construction depending on the system scale.

The data transmission device 1 that wants to start information transfer (2) in response to a request from the subordinate data processing device 2 selects free tokens (information transfer When it finds a token (that has not been used for a while), it is imported into the data transmission device 1, loaded with the destination data processing device address and transmission information received from the subordinate data processing device 2, and furthermore, the busy flag is set and the same token is transferred again. The token is returned to the transmission path using the channel. Once the token with the busy flag set is defined as a busy token (token that is currently transferring information), the busy state is released when the data transmission device 1 of the other party receives the information. It cannot be used by another data transmission device 1 until the busy token is sent to the transmission path. Therefore, once the busy token is sent to the transmission path, it continues to circulate around the ring until it is taken in by the data transmission device 1 of the other party.

In this state, the tokens corresponding to each channel on the transmission path are independently used for information transfer, so that transfer requests generated simultaneously within the system can be multiplexed for the number of channels.

FIG. 2 is a block diagram of a data transmission device according to an embodiment of the present invention. The device according to the embodiment of the present invention includes a receiving cable 1a constituting a ring, and a plurality of receiving channel circuits 11.1 connected to the receiving cable IPL. ...ll...11n, a reception control circuit 12 that controls signals from this reception interface circuit, and a reception circuit 13 that receives signals controlled from this reception control circuit 12. , and the receiving circuits are connected to each other by an external interface circuit 31 that receives signals from the receiving circuits.

Further, a transmission circuit 23 receives and transmits a signal from the external interface circuit 31, a transmission control circuit 22 controls and transmits a signal from this transmission circuit, and this transmission control circuit 2
Transmission channel circuit 21 that receives signals from 21. ...
Transmission interface circuit 2 having 21j...21n
1 and a transmission cable 1b which transmits the signal from this transmission interface circuit 21, a circuit on the transmission side is connected.

Furthermore, a data transmission device is constituted by a control circuit (equipment) that controls the entire transmission and reception described above, and a data processing device 2 that performs data processing.

The operation of the data transmission apparatus of this embodiment configured as described above will be explained. First, the operation when the data transmission device 1 is not a party to information transmission and reception will be described. In this case, free tokens and busy tokens from the upper data transmission device 1 are sent to the receiving channel circuit 1 in the receiving interface circuit 11 set for each channel.
1. ,...11. ,...11n, reception control circuit 12
, transmission control circuit 22, transmission channel circuits 2-1...21j,...21n in the transmission interface circuit 21
The signal is transmitted to the transmission cable 1b via the . At this time, the data transmission device 1 does not perform any control and simply functions as a part of the transmission path.

Next, an example of information transmission will be explained. When an information transfer request is issued by the data processing device 2, its state is stored in the control circuit 30 via the external interface circuit 31. The control circuit 30 provides 11. ,...
111, . . . 11 nK frequency-divided channels are monitored, and a request is made to detect fleet tokens from among the tokens passing through the local station. When a free token is detected, the control circuit 30 takes it in, and the data processing device 2
Request the destination station address and transfer information to be transferred.

The control circuit 30 stores the data set in the buffer in the transmission circuit 23 via the external interface circuit 31, changes the held fleet token into a busy token, and transfers control to the transmission control circuit 22. When the transmission control circuit 22 receives the control right from the control circuit 30, it adds a data set from the buffer in the transmission circuit 23 to the busy token, puts it on the transmission channel circuit 21, and sends it out to the transmission cable 1b.

Next, an example of information reception will be explained. When an information reception request addressed to the own station is made from another station using a token, the reception control circuit 12 confirms that the address belongs to the own station, and then
When the channel path is opened, information is stored in a buffer within the receiving circuit 13. The buffer in the receiving circuit 13 has a capacity for one packet (fixed length) and can sequentially take in input information.

On the other hand, the control circuit 30 sends a reception request to the data processing device fii2 when the own station address is confirmed by the reception control circuit 12. When the input of one packet is completed in the receiving circuit 13, the control circuit 30 receives a receivable signal from the data processing device 2 and starts transmitting the received information via the external interface circuit 31. At the same time, the busy token carrying this information is modified to a free token and returned to the transmission cable lb via the transmission control circuit 22. After all the information has been sent to the data processing device 2, the data transmission device 1 can again perform the next information transfer (input/output).

〔Effect of the invention〕

As described above, according to the device of the present invention, the data transmission device and the transmission path can be used by dividing the frequency, so that there are a plurality of transmission paths equimetrically, and the system as a whole can have multiple states in which simultaneous transmission and reception can be performed. This has the advantage of increasing transmission efficiency and enabling high-traffic data transmission.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a data processing system using a data transmission device according to an embodiment of the present invention. FIG. 2 is a block diagram of a data transmission device according to an embodiment of the present invention. ■...Data transmission device, 1a...100 receiving cable,
1b... Transmission cable, 2... Data processing device, 3
...Transmission cable, 11...Reception interface circuit, 114.11□, 11n...Reception channel circuit, 12...Reception control circuit, 13...Reception circuit, 21
... transmission interface circuit, 22 ... transmission control circuit, 23 ... transmission circuit, 30 ... control circuit, 31.
...External interface circuit. Patent applicant: NEC Corporation Representative Patent attorney: Naotaka Ide

Claims (1)

[Claims] (1) Three or more data transmission devices are connected in a ring through one transmission path, and tokens, which are the right to use the transmission path, are circulated through the transmission path, and each data transmission device uses one of the tokens. In a data transmission system configured to capture unused tokens and transmit data to another data transmission device, the one transmission path is a frequency division multiplexed transmission path; A data transmission method characterized in that the data transmission method is configured to circulate different tokens for each frequency, and each transmission device is configured to be able to select, capture and use a token for each frequency.