JPS60145751A - Data transfer system - Google Patents

Abstract

PURPOSE:To transmit a data even when a communication line is unstable by restoring a succeeding block to the alternate supervisory system so as to transfer data when a return signal is not returned and transferring data while repeating a prescribed step. CONSTITUTION:When a return signal ACK of the 1st block is received at a prescribed time, the data is transmitted by the 3-block simultaneous supervisory system from the data of the next 2nd block is transmitted. If the return signal ACK is not received at a prescribed time, the simultaneous supervisory system of the 1st one block, that is, the alternate supervisory system is used again.

Description

Detailed Description of the Invention (a) 8 Technical Field of the Invention The present invention relates to a data transfer method via a communication line, and particularly relates to a data transfer method via a communication line using a simultaneous monitoring method to improve transfer efficiency. It is something.

(b), Prior Art and Problems According to the prior art, the basics of data transfer via a communication line is that the sender sends an amount of data to the receiver, the receiver receives and checks the data, and If it is satisfactory, an ACK signal is returned to notify the transmitting side that reception has been completed. Upon receiving an ACK signal from the receiving side, the transmitting side determines that the previously sent data has been reliably received by the receiving side, and transmits the next data.

Data is transferred from the sending side to the receiving side by following these steps. However, in this method, it is necessary to wait for the arrival of an ACK signal between the first data transmission and the next data transmission, so the waiting time becomes a problem when a large amount of data is transmitted.

For this reason, a data transfer method based on a simultaneous supervisory method is used as a method to improve transfer efficiency.

FIG. 1 is an explanatory diagram showing an embodiment of a data transfer method based on a conventional simultaneous monitoring method.

In the figure, 5END is a transmitting device, REC is a receiving device, B]~
13n are blocks of data.

The data transfer method based on the conventional simultaneous monitoring method will be explained below with reference to the diagram.

First, the data to be transmitted from the transmitting device 5END is divided into a plurality of N pieces, and the first block Bl is sent to the receiving device RE.
Send to C.

At this point, the second block B2 is sent to the receiver R13C without waiting for the arrival of the ACK signal from the receiver REC.

Furthermore, the third block B3 is subsequently sent to the receiving device REC.

In this way, the signals are transmitted sequentially without waiting for the arrival of the ACK signal from the receiving device REC.

Eventually, A corresponding to the first block 81 is sent from the receiving device REC.
When the CK signal arrives at the transmitting device 5END, the transmitting device 5END confirms that the first block B1 has been correctly sent to the receiving device REC, and further sends the fourth block B4 to the receiving device RIEC.

Similarly, at this point, the second block B2 is sent from the receiving device REC.
By the arrival of the ACK signal corresponding to the transmitter 5END at the transmitter 5END, the transmitter 5END acknowledges that the second block B2 has been correctly sent to the receiver REC, and
Send block B5 to receiving device REC.

If the ACK signal corresponding to the second block B2 cannot be received, transmission starts again from the second block B2.

The time from when the transmitting device 5END transmits the first block Bl until it receives the ACK signal corresponding to the first block B1 varies depending on the transmission speed, data amount, checking method, etc. ACK corresponding to B1
The method of transmitting the fourth block of data B4 after confirming the signal is called the simultaneous monitoring method.

In this case, (4th block) - (1st block) is 3
Since there is a flock, the simultaneous monitoring method of rn-3 and B.)
. Of course, the larger the rTI value of the hole, the more efficient the transfer.

This type of data transfer method improves transfer efficiency, but if the communication line is unstable, an ACK signal cannot be obtained and it is necessary to return to the original state and send the data again, which reduces the frequency of both transmissions. There was a drawback that if there were too many, it would actually become inefficient.

(C)0Object of the invention The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art,
The purpose is to propose a data transfer method that can efficiently transmit data even when the communication line is unstable.

According to the present invention, in a method in which data to be transferred is divided into a plurality of blocks and each block is sequentially transferred, the first block is transferred after data transfer. Said first
After receiving the ACK signal corresponding to the block, the data is transferred by an alternate monitoring method that moves to the next step, and if the ACK signal is returned at a predetermined time, the predetermined step after the second step is performed. Data is transferred sequentially for a plurality of blocks, and if the ACK signal is returned at a predetermined time, subsequent blocks sequentially transfer data for a plurality of blocks of higher order, and then If the ACK signal is not returned at a predetermined time, in any case, subsequent blocks return to the switching T1 and monitoring method and transfer data,
This is achieved by providing a data transfer method characterized by transferring data while repeating the above procedure.

(e) 9 Embodiments of the Invention FIG. 2 is an explanatory diagram showing an embodiment of the data transfer system according to the present invention.

In the figure, all symbols and numbers are the same as in FIG. 1.

In the present invention, as with the conventional method, the first method (32 position 5E
Divide the data to be transmitted from the ND into multiple N pieces,
The first block B1 thereof is sent to the receiving device RPC.

When sending the first block, the first block receives 8 CK signals corresponding to the first block, and then moves to the next step. However, if this ACK signal is received within a predetermined time, the next step is sent. From the time of sending the second block of data, data is sent using, for example, the nl-3 simultaneous monitoring method.

Transfer the data of each block sequentially in this way, m = 3
If the transfer is possible without error using the simultaneous monitoring method, further m
=5 data is transferred using the simultaneous monitoring method, and if an ACK signal cannot be received at a predetermined time, the data is transferred again using the initial m=l
Return to the simultaneous monitoring method (referred to as the alternating monitoring method).

By transmitting data in this order, it is possible to efficiently transmit data even if there is an unstable element in the communication line.

(``) 1. Effects of the Invention As explained in detail above, according to the present invention, a major effect is that it is possible to realize a data transfer method that can efficiently transmit data even when the communication line is unstable. There is.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of a one-way data transfer method based on a conventional simultaneous monitoring method. FIG. 2 is an explanatory diagram showing an embodiment of the data transfer method according to the present invention. In the figure, 5END is a transmitting device, REC is a receiving device, Bl-
Each Bn is a block of data.

Claims (1)

[Claims] In a method in which data to be transferred is divided into a plurality of blocks and each block is sequentially transferred, the first block moves to the next step after receiving an ACK signal corresponding to the first block after data transfer. Data is transferred by an alternating monitoring method, and if an ACK signal is returned at a predetermined time, a predetermined number of tlil after the second block is transmitted.
Data is transferred sequentially for the + blocks, and if the ACK signal is returned at a predetermined time, subsequent blocks are sequentially transferred data for a plurality of blocks of higher order,
In that case, if the ACK signal is not returned at a predetermined time, the subsequent blocks return to the alternate monitoring method and transfer data, and the above procedure is repeated while data is transferred. Data transfer method.