JP3428883B2 - Data communication method and data communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables high-speed recovery from a temporary failure and efficient communication when data is transmitted / received using a transmission line without quality guarantee. The present invention relates to a possible data communication method and a data communication device.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing packet exchange by a conventional data communication apparatus. In a conventional data communication device, delivery confirmation of packet-divided data is performed for each packet. Specifically, when the transmitting side transmits packet 1, the receiving side receives packet 1,
Immediately after that, ACK for packet 1 is returned to the transmitting side. By the sender receiving the ACK for packet 1,
The packet 2 to be transmitted next is transmitted. The transmitting side similarly transmits up to the final packet after transmitting the packet 2, and the ACK for the final packet is returned to the transmitting side to complete the data transmission.

Next, a description will be given of a data communication apparatus in the case where a transmission line is restored after a packet has temporarily stopped due to some failure on the transmission line. FIG. 6 is a configuration diagram showing a state that occurs when a failure occurs in a conventional data communication device. For example, when the transmission line is restored after some failure occurs on the transmission line and the packet temporarily stops, for example, as shown in FIG.
If a failure occurs during the transmission of the packet and the transmission path is restored after that, the transmitting side times out while waiting for the ACK for the packet 3 from the receiving side. Then, the transmitting side retransmits the packet 3, but at that time, since the transmission path is restored, the packet 3 can be received by the receiving side, and an ACK for the packet 3 is returned to the transmitting side. Next, the sender sends packet 3
After receiving the ACK for the packet, the packet transmission until the end of the packet and the confirmation of the ACK are repeated.

Next, a data communication apparatus will be described in the case where a device is connected to a transmission line in such a configuration that the data transmitting side and the data receiving side are interchanged. FIG. 7 is a block diagram showing a method of exchanging a data transmitting side and a data receiving side in a conventional data communication apparatus. When a device is connected to a transmission line in such a configuration that the data transmitting side and the data receiving side are exchanged, conventionally, as shown in FIG. 7, the connection request packet 11 from the data transmitting side and the receiving side are After exchanging the packet 12 for indicating the connection permission returned to the transmitting side, data is transmitted and received by the method shown in FIG.

Specifically, the data transmitting side transmits a packet 11 including a connection request to the receiving side, and when the receiving side can process, returns a packet 12 indicating a connectable state, or when the receiving side cannot process the packet. Packet 12 indicating that connection is impossible
The packet of the data part is transmitted in order from the packet 1 only when the packet 12 indicating that connection is possible is returned to the transmitting side.

Next, a data communication device in which the contents of two data parts are the same will be described. FIG. 8 is a configuration diagram showing a data transmission method when the contents of two data parts are the same in the conventional data communication device. In the conventional data communication device, when the contents of the data parts of the packet 6 and the packet 7 are the same as in the example shown in FIG. 8, the data is transmitted twice, duplication of the data occurs, and the transmission efficiency can be improved. could not.

[0007]

Since the conventional data communication method and data communication apparatus are configured as described above, since the receiving side needs to return an ACK for each packet transmitted by the transmitting side, it has data. As many ACK packets as the number of packets pass through the transmission line, and there is a problem that the transmission line cannot be used efficiently.

Further, as shown in FIG. 6, when a temporary failure occurs in the transmission line, the transmission line is free from the time when the packet 3 is transmitted until the timeout without ACK for the packet 3 is reached. However, there was a problem that the use efficiency of the transmission line deteriorates. Further, when performing communication in which transmission and reception of data are frequently exchanged, conventionally, there is a problem that extra time other than data transfer is taken because connection / disconnection processing of the line is performed every time transmission / reception is exchanged. . Further, when the data in the packet is the same as the one in the packet transmitted last time, the same data was transmitted, which took time and was inefficient.

The present invention has been made in order to solve the above problems. When data is transmitted, a serial number of the packet is added to the packet to eliminate the need for ACKs other than the first and last packets, and a failure occurs. Sometimes the receiving side requests the sending side to retransmit from undelivered packets,
An object of the present invention is to obtain a data communication method and a data communication device that minimize the recovery time and efficiently use a transmission path.

Further, based on this method, there is provided a data communication method and a data communication device capable of reducing the overhead of exchanging data transmission / reception and improving the efficiency of data transmission by compressing duplicate data. The purpose is to get.

[0011]

In the data communication method according to the present invention, after transmitting the first packet from the transmitting means, the receiving means confirms the serial number in the packet and returns an ACK to the transmitting means. The transmitting means waits for the ACK from the receiving means, continuously transmits the second and subsequent packets after the ACK is returned, waits for the ACK from the receiving means even after the last packet is transmitted, and returns this ACK. The transmission process is completed when the transmission is completed.

In the data communication method according to the present invention, when a packet is dropped due to a failure in the transmission line and the next packet arrives at the receiving means, the receiving means detects the dropped packet and the dropped packet is detected. Requesting retransmission from the receiving means and the transmitting means receives the retransmission request signal of the packet not received from the receiving means, changes the packet to be transmitted next to a packet based on the retransmission request signal and continues data transmission. It is the one.

In the data communication method according to the present invention, when a packet having the same data portion as the immediately preceding packet is transmitted, the transmitting means indicates that the data of the packet transmitted last time and the data of the packet transmitted this time are the same. The duplication flag is set in the header part of the packet and transmitted, and the reception means checks the duplication flag of the packet from this transmission means. If this duplication flag is set, the data part of the previously received packet should be copied. It is the one.

[0014]

In the data communication apparatus according to the present invention, the transmitting means transmits the first packet and then the ACK from the receiving means.
Waiting for the ACK, the second and subsequent packets are continuously transmitted after the ACK is returned, the ACK from the receiving means is waited even after the last packet is transmitted, and the transmission processing is completed by returning the ACK, The receiving means confirms the serial number in the packet and returns the ACK to the transmitting means after receiving the first packet and the last packet.

[0016]

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a block diagram showing a data communication method according to Embodiment 1 of the present invention. In FIG. 1, 10 is an ACK from a receiving means 20 after the first packet 1 is transmitted.
Is a transmission means for continuously transmitting the packet 2 and subsequent packets after the ACK is returned, waiting for the ACK from the reception means 20 even after the last packet is transmitted, and the ACK is returned, thereby completing the transmission processing. . Reference numeral 20 is a receiving unit that returns the ACK to the transmitting unit 10 after receiving the first packet and the last packet by looking at the serial number in the packet.

Next, the operation will be described. Transmission means 10
Is the AC from the receiving means 20 after the first packet 1 is transmitted.
Waiting for K, transmitting packets 2 and subsequent packets continuously after ACK is returned, waiting for ACK from the receiving means 20 even after the last packet is transmitted, and returning ACK, the transmission processing is completed. The receiving means 20 looks at the serial number in the packet, and after receiving the first packet and the last packet, returns ACK to the transmitting means 10 to complete the transmission.

As described above, according to the first embodiment, the transmitting means 10 limits the position of the packet for confirming the ACK to only the first packet and the last packet for the connection of the line. Is transmitted, so that it is possible to obtain the effect that the transmission efficiency can be improved.

Embodiment 2. FIG. 2 is a block diagram showing a data communication method according to a second embodiment of the present invention. In FIG. 2, reference numeral 30 indicates a packet to be transmitted next when a retransmission request signal of a packet not received from the receiving means 40 is received. The transmitting unit 40, which changes the packet based on the resend request signal and continues data transmission, detects, for example, packet 3 dropout and packet 3 dropout when packet 3 is dropped due to a failure in the transmission path, and packet 3 dropout is detected. Is a receiving means for requesting the transmitting means 30 to retransmit the data.

Next, the operation will be described. Receiving means 40
Caused a failure in the transmission path, and for example packet 3 was dropped,
When the packet 4 arrives, the dropout of the packet 3 is detected, and a retransmission request signal for requesting the retransmission from the packet 3 is returned. Next, when the transmitting means 30 receives this retransmission request signal, it immediately changes the data to be transmitted to the packet 3 and continues the data transmission.

As described above, according to the second embodiment, there is no need to wait for a packet loss due to a timeout as in the conventional case, so that even if a failure occurs, it is possible to recover early. can get.

Embodiment 3. 3 is a block diagram showing a data communication method according to a third embodiment of the present invention. In the figure, when transmitting a packet having the same data portion 52 as the previous packet, 50 is a header in the packet to be transmitted. This is a transmission unit that sets the duplication flag of the unit 51 and indicates that the data in the packet transmitted last time and the data in this packet are the same. Reference numeral 60 is a receiving means for confirming the duplication flag in the packet from the transmitting means 50 and copying the data portion 52 of the previously received packet when this duplication flag is set.

Next, the operation will be described. Transmission means 50
When transmitting a packet having the same data portion 52 as the previous packet, the header portion 51 in the packet to be transmitted is
The duplicate flag is set to indicate that the data in the previously transmitted packet and the data in this packet are the same. The receiving means 60 confirms the duplication flag in the packet, and when the duplication flag is set, copies the data portion 52 of the previous reception packet. Therefore, the previous data section 5
When 2 and the data section 52 of this time are the same, the transmitting unit 50 may transmit only the header section 51.

As described above, according to the third embodiment, when the data part 52 of the packet to be transmitted is the same as the data part 52 of the immediately preceding packet, the receiving means 60 is provided.
Since the data section 52 is copied in step 1, the effect that the data transmission time can be saved can be obtained.

Fourth Embodiment 4 is a block diagram showing a data communication method according to a fourth embodiment of the present invention. In the figure, reference numeral 70 denotes a packet from the second transmission / reception unit 80 after the transmission / reception exchange flag is added to the final packet. The first transmitting / receiving means 80 shifts to the receiving process by receiving the first packet of the first packet, and after receiving the packet with the transmission / reception exchange flag set, 80 prepares the data to be transmitted, and ACKs the final packet that should originally be transmitted. 2nd to send the first of the transmitted packets instead of
It is a means of transmitting and receiving.

Next, the operation will be described. The first transmission / reception unit 70 attaches a transmission / reception exchange flag to the final packet and transmits it to the second transmission / reception unit 80. After receiving the packet in which this flag is set, the second transmitting / receiving means 80 immediately prepares the data to be transmitted, replaces the ACK for the last packet which should be originally transmitted, and sets 1 of the transmitted packet.
The second item is transmitted to the first transmitting / receiving means 70. The first transmission / reception unit 70 receives the first packet from the second transmission / reception unit 80, and immediately shifts to the reception process.

As described above, according to the fourth embodiment, the transmission / reception directions of data can be exchanged without performing connection processing, so that there is an effect that the transmission path can be used efficiently. can get.

[0029]

As described above, according to the present invention, after transmitting the first packet from the transmitting means, the receiving means confirms the serial number in the packet and returns an ACK to the transmitting means, and then the transmitting means. Then, wait for the ACK from the receiving means, continuously transmit the second and subsequent packets after the ACK is returned, wait for the ACK from the receiving means even after the last packet is transmitted, and return this ACK. Since the transmission processing is completed by the above, there is an effect that the transmission efficiency can be improved.

According to the present invention, when a packet is dropped due to a failure in the transmission line and the next packet arrives at the receiving means, this receiving means detects the dropped packet and retransmits from this dropped packet. And the transmitting means receives the retransmission request signal of the packet not received from the receiving means, changes the packet to be transmitted next to a packet based on the retransmission request signal, and is configured to continue the data transmission. Therefore, even if a failure occurs, there is an effect that it can be recovered early.

According to the present invention, when transmitting a packet having the same data portion as the previous packet, the transmitting means sets a duplication flag indicating that the data of the packet transmitted last time and the data of the packet transmitted this time are the same. The header section of the packet is set up for transmission, the receiving means checks the duplication flag of the packet from this sending means, and if this duplication flag is set, the data section of the previously received packet is copied. Therefore, there is an effect that the data transmission time can be saved.

[0032]

According to the present invention, the transmitting means waits for an ACK from the receiving means after transmitting the first packet, and
The second and subsequent packets are continuously transmitted after the CK is returned, and the AC from the receiving means is transmitted even after the last packet is transmitted.
Waiting for K, the transmission process is completed by returning this ACK, the receiving means confirms the serial number in the packet, and returns the ACK to the transmitting means after receiving the first packet and the last packet. Since it is configured, there is an effect that the transmission efficiency can be increased.

[0034]

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a data communication method according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a data communication method according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a data communication method according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a data communication method according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing packet exchange by a conventional data communication device.

FIG. 6 is a configuration diagram showing a state that occurs when a failure occurs in a conventional data communication device.

FIG. 7 is a configuration diagram showing a method of exchanging a data transmission side and a data reception side in a conventional data communication apparatus.

FIG. 8 is a configuration diagram showing a data transmission method when the contents of two data parts are the same in the conventional data communication device.

[Explanation of symbols]

10, 30, 50 transmitting means, 20, 40, 60 receiving means, 70 first transmitting / receiving means, 80 second transmitting / receiving means.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 29/08 H04L 12/56

Claims (4)

(57) [Claims] 1. After transmitting the first packet from the transmitting means, the receiving means confirms the serial number in the packet and
CK is returned to the transmission means, the transmission means waits for an ACK from the reception means, the second and subsequent packets are continuously transmitted after the ACK is returned, and the reception means also transmits the last packet. Wait for ACK of this AC
A data communication method characterized in that transmission processing is completed when K is returned. 2. When a failure occurs in a transmission line and a packet is dropped and the next packet arrives at the receiving means, the receiving means detects the dropped packet, requests retransmission from the dropped packet, and transmits the packet. The means, when receiving the retransmission request signal of the packet not received from the receiving means, changes the packet to be transmitted next to the packet based on the retransmission request signal, and continues the data transmission.
Described data communication method. 3. When transmitting a packet having the same data portion as the previous packet, the transmitting means sets a duplication flag indicating that the data of the packet transmitted last time and the data of the packet transmitted this time are the same as the header portion of the packet. 2. The data part of the packet received last time is copied when the duplication flag of the packet from the sending means is confirmed by the receiving means and the duplication flag is set in the receiving means. Alternatively, the data communication method according to claim 2. 4. An ACK from the receiving means after waiting for an ACK from the receiving means after transmitting the first packet, continuously transmitting the second and subsequent packets after the ACK is returned, Wait for the ACK and confirm the serial number in the packet and the transmission means that completes the transmission process by returning this ACK, the first packet,
And a receiving means for returning the ACK to the transmitting means after the last packet is received .