JPH08163128A - Confirmation system for broadcast transmission - Google Patents

Abstract

PURPOSE: To provide a confirmation system which can confirm the broadcast transmission and also can effectively transmit and receive the confirmation of this transmission despite of a large number of stations that are connected to a transmission line. CONSTITUTION: In a transmission system where the transmission is confirmed by the broadcast transmission, a data transmitter station 1 adds the received transmission confirmation information ACK5 when the data are transmitted again. The data receiver stations 2, 3 and 4 perform no transmission as long as the information ACK5 is set and then transmit the transmission confirmation ACK6 when the received information of each own station is not set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local area network (LAN) broadcast transmission system, and more particularly to a delivery confirmation system for broadcast transmission.

[0002]

2. Description of the Related Art In a network composed of a plurality of stations, when data is transmitted from one station to all other stations,
Broadcast transmission is used. Also, to confirm that the data has arrived at the other station,
Individual transmission must be performed in order for each station to confirm delivery.

When it is desired to transmit data from the master station on the transmission path to all other slave stations and to confirm that the data has reached all the partner stations which are slave stations, generally, FIG. As shown, the data transmitting station 1 transmits the data signal S0 to the data receiving stations 2, 3 and 4 by broadcast transmission. The stations 2, 3 and 4 which have received the data are individually transmitted and acknowledged (ACK) signals ACK2, ACK3 and AC.
Send K4 to station 1. The station 1 determines that the transmission has succeeded because all the stations responded to the delivery confirmation. here,
If the station 1 cannot correctly receive any of the acknowledgment signals ACK2, ACK3, and ACK4, the station 1 detects a time-out and retransmits the data. Stations 2, 3, 4
If the retransmission data has already been received, when the retransmission data is received again, it discards it and sends only the acknowledgment signal to the station 1. The station 1 continues the above process until it receives the delivery confirmation from all stations or until the number of retransmissions is reached.

[0004]

When the number of stations on the transmission path is small, the above method is not a problem, but when the number of stations is large, the station 1 receives the delivery confirmation from all stations in a concentrated manner. , The load factor is high, and the possibility of missing the delivery confirmation is high. Therefore, the station 1 retransmits the data many times, which is inefficient.

The present invention has been made in view of the above problems, and an object thereof is to confirm delivery of broadcast transmission, which enables efficient transmission / reception of delivery confirmation even when the number of stations connected to the transmission path is large. It is to provide a method.

[0006]

In order to achieve the above object, a delivery confirmation system for broadcast transmission according to the present invention comprises:
In the delivery confirmation method, the data transmission station broadcasts data to the data reception station, and the data reception station transmits a delivery confirmation for confirming that the data has been delivered to the data transmission station by individual transmission. Adds the delivery confirmation received information when retransmitting the data, and the data receiving station does not send another delivery confirmation to the data transmitting station when the delivery confirmation received information is set, and the delivery confirmed When the received information of the own station is not set in the information, the delivery confirmation is transmitted to the data transmitting station.

[0007]

In the transmission method of confirming delivery by broadcast transmission, the data transmitting station transmits data by broadcast. The data receiving station transmits the delivery confirmation to the data transmitting station by individual transmission. When data is retransmitted, delivery confirmation received information is added. The retransmission data receiving station does not transmit the delivery confirmation when it finds out that the delivery confirmation received information in the retransmission data receiving station has already received the delivery confirmation of its own station. Similarly, a station whose reception confirmation information of its own station is not set in the transmission confirmation reception information transmits a transmission confirmation. The data transmitting station repeats the data retransmission until the delivery confirmation is received from all the stations.

[0008]

Embodiments of the present invention will be described below with reference to FIGS.

1 and 2 are schematic views of a delivery confirmation system according to an embodiment of the present invention. 1 and 2, the same or corresponding members as those in FIG. 5 are designated by the same reference numerals. As shown in FIG. 2, transmission data S1 from the data transmission station 1
The data receiving stations 2, 3, and 4 transmit the delivery confirmation signals ACK2, ACK3, and ACK4 to the data transmitting station 1, but the delivery confirmation signal ACK4 of the data receiving station 4 does not reach the data transmitting station 1. In that case, as shown in Figure 1,
The station 1 retransmits the data SD. At this time, information ACK5 indicating that the delivery confirmation signals ACK2 and ACK3 from the stations 2 and 3 have already been received is added. The stations 2 and 3 which confirmed this did not confirm the delivery because it was found that the delivery confirmation of their own station reached the station 1. Since the station 4 finds that the delivery confirmation signal ACK4 of its own station has not reached the station 1, it sends the delivery confirmation information ACK6 to the station 1.

FIG. 3 shows the operation of the data transmitting station 1, and FIG. 4 shows the operation of the data receiving stations 2, 3 and 4 in a flow chart.
FIG. 3 is a flowchart of the data transmission processing operation of the station 1. As shown in FIG. 3, when transmitting from the station 1, the delivery confirmation ACK flags for all stations are cleared in step S1, and the retransmission counter is reset to zero in step S2. Step S
The time-out timer is started in step 3, and the process proceeds to step S4 to transmit data. At this time, the ACK flags are all zero. In step S5, it is determined whether a time-out has occurred. If the timeout has occurred in step S5, the process proceeds to step S7, the retransmission counter is incremented, and the process proceeds to step S8. In step S8, it is determined whether or not the retransmission counter is up. If not, the process proceeds to step S9, the timeout timer is activated, and the process proceeds to step S10. Data is retransmitted in step S10.
At this time, a delivery confirmation ACK flag is added. Step S
If the retransmission counter is up in step 8, error processing is executed.

If it has not timed out in step S5, the process proceeds to step S6 to receive the ACK, and if it has timed out, the process proceeds to step S12 to increment the ACK flag of the station and proceeds to step S13. Step S
In 13, it is judged whether or not all the stations have received the data. If all the stations have received the data, the process proceeds to step S14 to complete the process.

FIG. 4 shows the data reception processing operation of the stations 2, 3 and 4, and shows the data reception processing of the station 2, for example. When the station 2 receives the data, it is determined in step S15 whether or not the data is already received. If the data is not already received, the process proceeds to step S16 to save the received data. Next, in step S17, a delivery confirmation (ACK) signal is transmitted.
In step S15, if the received data is from the station 1, the process proceeds to step S18, and it is determined whether or not the flag of the delivery confirmation signal ACK of the own station is "1". If the flag is "1", the operation ends, and if the flag is not "1", the process proceeds to step S17.

As described above, when the station 1 cannot receive the delivery confirmation from all the stations, the retransmission processing is performed, and the other station transmits the delivery confirmation to the station 1 again. In order to reduce the load of the delivery confirmation reception processing of the station 1, it is only necessary that the station receiving the retransmission data does not send the delivery confirmation. However, if it is not confirmed that the delivery confirmation has correctly arrived at the station 1, the transmission efficiency will be reduced. Therefore, when the station 1 transmits the data, it adds the station number that has already received the delivery confirmation.

[0014]

The present invention is as described above. The data transmitting station adds the delivery confirmation received information when retransmitting the data, and the data receiving station receives the delivery confirmation received information when the delivery confirmation received information is set. If the delivery confirmation is not sent to the data transmitting station again and the delivery confirmed information is not set to the received information of the own station, the delivery confirmation is transmitted to the data transmitting station. Even if there are a large number of stations connected to, it is possible to efficiently transmit and receive the delivery confirmation without performing unnecessary transmission and reception processing of the delivery confirmation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a delivery confirmation method of broadcast transmission according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a delivery confirmation method of broadcast transmission according to an embodiment of the present invention.

FIG. 3 is a data transmission processing flowchart of the data transmission station in the delivery confirmation method of broadcast transmission according to the embodiment of the present invention.

FIG. 4 is a data reception processing flowchart of the data reception station in the delivery confirmation method of broadcast transmission according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional broadcast transmission system.

[Explanation of symbols]

 1 ... Data transmitting station 2, 3, 4 ... Data receiving station

Claims (1)

[Claims] 1. A delivery confirmation method in which data is transmitted from a data transmitting station to a data receiving station by broadcasting, and the data receiving station transmits a delivery confirmation confirming that the data has been delivered to the data transmitting station by individual transmission. , The data transmitting station adds the delivery confirmation received information when retransmitting the data, and the data receiving station does not send the delivery information again to the data transmitting station when the delivery confirmation received information is set. A delivery confirmation method for broadcast transmission, characterized in that a delivery confirmation is transmitted to the data transmitting station when the received confirmation information of the own station is not set in the delivery confirmed information.