JP3168894B2 - Data transmission device and data transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a data transmission technique for transmitting packet data using a wireless or wired transmission path.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a configuration diagram of a conventional data transmission device disclosed in Japanese Patent Application Laid-Open No. 4 (1994) -104, wherein 100 is a master station, 101 is a slave station, 102 is a communication satellite,
103 is a host computer connected to the main station 100,
104 is a data terminal connected to the slave station 101. 110-1 and 111-1 are terrestrial line interface units in the master station 100 and the slave station 101;
1-2 is a satellite link level management section in the master station 100 and the slave station 101, and 110-3 and 111-3 are satellite link management sections in the master station 100 and the slave station 101.

Next, the operation will be described. When transmitting packet data from the host computer 103 to the data terminal 104, the host computer 103 and the main station 100
Data link protocol on the ground line between the master station 1
Packet data is transmitted via a data link protocol on a satellite link between the slave station 101 and the slave station 101 and a data link protocol on a terrestrial link between the slave station 101 and the data terminal 104.

[0004]

In the conventional data transmission apparatus, when packet data is transmitted via a plurality of data link protocols, each data link protocol is independent. If the error detection and the retransmission of the error packet are performed, and the reception of the packet data is not completed in the preceding data link protocol in order, the packet data transmission in the next data link protocol cannot be started.

For this reason, when packet data is transmitted using a transmission line via a plurality of data links, such as a satellite link having a large transmission delay, a wireless link having a high transmission error rate, or a wire link, a transmission from a transmitting terminal to a receiving terminal is required. However, there has been a problem that the data transmission delay becomes large and the throughput is not improved.

In addition, since the collision between the retransmission of the lost packet from the packet transmitting side and the transmission of the packet retransmission request packet from the packet receiving side occurs for each data link protocol in one terminal-to-terminal link, particularly, In a transmission line in which a transmission medium is shared by a plurality of communication channels, there has been a problem that the use efficiency of the transmission line is reduced due to invalid packet transmission / reception, and a processing load on a data transmission device is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a high transmission error rate such as a geostationary satellite line, a low-orbit satellite line, a cellular radio line, or a wired line. To reduce end-to-end data transmission delay, increase line utilization efficiency, and increase throughput in a transmission line that transmits packet data via a plurality of data links including a line with a large data transmission delay. With the goal.

[0008]

[Means for solving the problems ] To solve the above problems,
Data transmission apparatus according to the present invention
Indicates that the received status of the received packet is normal / invalid
Sequentially decision in, out of the normal packet to discard the illegal packets
From the packet determining means for
Identification information of the packet included in the output normal packet
Based on the identification number of the discarded illegal packet.
ID number recognizing means and retransmission of the invalid packet
Generates the requested retransmission request packet, and
Retransmission request packet transmitting means for transmitting to a device
Request means and normality output from the packet determination means
The packet is re-transmitted by the
Do not wait until the data is always received.
Data transmission means for transmitting data to the data transmission device.
It is characterized by.

In addition, a dummy packet including identification information of an invalid packet requested to be retransmitted by the retransmission request unit and retransmission request information indicating that retransmission of the invalid packet has been requested is generated, and the dummy packet is added to the invalid packet. A retransmission requested information packet control means for outputting the corresponding normal packet to the packet transmission means is provided.

[0010] Further, the illegal packet information adding means for adding the identification information of the illegal packet to the normal packet as illegal packet identification information and outputting the information to the packet transmitting means, and the illegal packet identification information added to the received normal packet. Based on the illegal packet information detecting means to be detected, and the illegal packet identification information detected by the illegal packet information detecting means, of the illegal packets detected by the packet determining means , And an immediately preceding illegal packet detecting means for detecting and controlling the immediately preceding illegal packet retransmission request to be transmitted by the retransmission request packet transmitting means.

Further, a dummy packet including the retransmission requested information is
When receiving a packet, it is provided with a delivery confirmation transmission means for transmitting acknowledgment information for the packet to the sender.

A retransmission time storing means for storing a retransmission packet transmission time; a retransmission time stored in the retransmission time storage means; and a time at which the retransmission request signal corresponding to the packet in which the retransmission time is stored is received. Packet retransmission control means for determining the necessity of retransmission of a packet based on.

A retransmission request time storing means for storing a time at which the retransmission request signal is transmitted by the retransmission request means;
Based on the retransmission request time stored in the retransmission request time storage means and the time at which a retransmission request signal corresponding to the packet in which the retransmission request time is stored is received, the retransmission request information packet control means And a retransmission requested information packet transmission control means for determining whether retransmission of the completed information packet is necessary.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a network configuration diagram showing an embodiment of a network using a data transmission device according to the present invention.
b, 1c and 1d are data transmission devices according to the present invention, 2
a and 2b are data terminals connected to the data transmission devices 1a and 1d. Reference numeral 3 denotes a mobile satellite line using low-orbit satellites, 4 denotes a satellite line using geostationary satellites, and 5 denotes a cellular mobile communication line.

Next, the operation will be described. From the data terminal 2a shown in FIG. 1 to the data terminal 2b, a mobile satellite link 3 using low-orbit satellites, a satellite link 4 using geostationary satellites,
A case where packet data (hereinafter, referred to as a packet) is transmitted via the cellular mobile communication line 5 will be described. First, each of the data transmission devices 1a and 1b for transmitting and receiving packets using the mobile satellite circuit 3 using low-orbit satellites has a built-in data link protocol communication function.
A transmission sequence number is assigned to each packet transmitted from the data transmission device 1a to the data transmission device 1b. When a bit error or the like occurs in the packet during transmission and the packet is lost, the data transmission device 1a transmits the packet via this link. By retransmitting the lost packet, all data can be transmitted without packet loss.

Also, in the case of the data transmission devices 1b and 1c for transmitting and receiving packets via the satellite line 4 by geostationary satellites, the data transmission devices 1c and 1d for transmitting and receiving packets via the cellular mobile communication line 5 are also used. In this case as well, each of them can similarly incorporate a data link protocol communication function and transmit all data without loss of packets.

The conventional data link protocol aims at preventing packet loss on a single link and guaranteeing the packet order. Therefore, when the packet loss is detected in the data transmission device on the reception side, a request for retransmission of the lost packet is made to the data transmission device on the transmission side, and the normally received packets after the lost packet are discarded or suspended, Until the lost packet is retransmitted from the transmitting data transmission device, it cannot be directly processed as valid packet data. For this reason, satellite lines,
When packet data is transmitted via a plurality of lines having a high data error rate due to a large data transmission delay such as a wireless line or a low-speed terrestrial line of poor quality, the end-to-end transmission increases as the number of links through the line increases. The delay increases.

According to the present invention, when performing end-to-end communication via a plurality of individual links, one link spanning the plurality of individual links is assumed as a cascade link, and each individual link is lost. The end-to-end data transmission delay is reduced by transmitting a normally received packet having a sequence number subsequent to that of the lost packet to the next-stage data transmission device without waiting for retransmission of the lost packet. Is to improve.

Hereinafter, a cascade link is used between the data transmission devices at both ends of data transmission via a plurality of links, and the data transmission device 1a at the data transmission end is referred to as the originating data transmission device, and the data reception device at the data reception end. Is referred to as a destination data transmission device, and the data transmission devices 1b and 1c for transferring received data to a next-stage data transmission device are referred to as relay data transmission devices.

FIG. 2 is a configuration diagram of the data transmission devices 1a, 1b, 1c, 1d in this embodiment. Numeral 10 denotes an illegal packet detecting means as a packet judging means for judging whether or not the received packet is normal or invalid, which discards the illegal packet and outputs a normal packet. 1
Reference numeral 1 denotes identification number recognition means for detecting identification numbers of normal and illegal packets based on identification information such as the sequence number of normal packets output from the illegal packet detection means 10;
2 is a packet transmission information storage means for storing identification numbers of normal and illegal packets detected by the identification number recognition means 11, and 13 is a packet transmission information storage means 12.
A retransmission request packet transmitting means for transmitting a retransmission request signal to the preceding data transmission device based on the identification number of the invalid packet stored in the storage unit, said identification number recognizing means 11, packet transmission information storage means 12, retransmission request packet transmitting means 1
3 forms retransmission request means.

The packet transmission information storage means 12
The identification number of the invalid packet stored in the storage unit is, for example, specifically, the sequence number of the lost packet. Reference numeral 14 denotes a packet transmission control unit as a packet transmission unit that inputs a normal packet output from the unauthorized packet detection unit 10 through the identification number recognition unit 11 and sequentially transmits the packet to the next data transmission device. Reference numeral 15 denotes an order queue storage unit for rearranging the packets in the original packet order. Although not shown, retransmission means is provided for retransmitting the packet in response to a retransmission request from the next stage.

Next, the operation will be described. The packets received by the outgoing data transmission device 1a and the relay data transmission devices 1b, 1c are
The packet is checked by a frame check sequence or the like added to the packet, and an illegal packet having a bit error is discarded. The packet having no bit error is sent to the identification number recognition means 11. The identification number recognition means 11 detects an unauthorized packet based on the identification information of the packet. Here, for example, if the transmission sequence number is used as the identification information, the identification number recognition means 11 always recognizes the packet sequence number expected to be received next, and the sequence number of the transmitted packet is Check if the expected packet sequence number.

If the sequence number is expected to be received,
This packet is sent to the packet transmission control means 14 as a normal packet, and the sequence number expected to be received is updated. If the sequence number (for example, n) of the packet is a sequence number larger than the expected number (for example, m), the packet is received immediately before the received sequence number m (m−1) from the expected sequence number n. ) Are recognized as packets that have been lost in the preceding link or the preceding data transmission device, or have become invalid and have been discarded by the illegal packet detecting means 10. Thus, a lost packet is detected.

This detection result is stored in the packet transmission information storage means 12 as the sequence number of the lost packet. Based on the lost packet sequence number stored in the packet transmission information storage means 12, retransmission request packet transmission means 13
Generates a retransmission request packet and sends it to the preceding data transmission apparatus, which is the transmission source, to request retransmission of the lost packet. The retransmission request from the originating data transmission device 1a to the data terminal 2a or the relay data transmission device 1b, 1c to the preceding data transmission device is a reject packet (retransmission request packet) requesting retransmission of all packets after the lost packet, or A selective reject packet (selective retransmission request packet) or the like that requests retransmission of only a packet having one or a plurality of designated sequence numbers is used.

On the other hand, the packet output from the identification number recognition means 11 as a normal packet having the expected sequence number is input to the packet transmission control means 14. The packet transmission control means 14 sequentially transmits the input packets,
The data is transmitted to the next-stage data transmission device. Even for a normal packet having a sequence number higher than the expected sequence number, a sequence number that skips the sequence number of the lost packet is added without waiting for the lost packet to be retransmitted. Send to device. In this case, the expected sequence number is not updated. And the identification number recognition means 11
If the input sequence number of the normal packet is the sequence number stored as a lost packet in the packet transmission information storage unit 12, the sequence number is recognized as a retransmission packet from the previous stage, and other packets are recognized. The packet is sent to the packet transmission control means 14 without waiting for the reception of the lost packet, and the sequence number is deleted from the packet transmission information storage means 12. Update the number. The packet transmission control means 14 adds a sequence number that skips the sequence number of the lost packet at that time, and transmits the packet to the next-stage data transmission device.

If a packet having a sequence number larger than the expected sequence number is input to the identification number recognition means 11, a retransmission request has been completed for the sequence number stored in the packet transmission information storage means 12. So
For other sequence numbers, a retransmission request may be made using the selective reject packet.

The operation of the outgoing data transmission device 1a and the relay data transmission devices 1b and 1c has been described above. Next, the operation of the destination data transmission device 1d will be described. Here, in order to finally output the packet to the data terminal 2b, it is necessary to correctly rearrange the packet order and transmit the packet. Therefore, the order queue storage unit 15 operates. In the destination data transmission device 1d, the operation of detecting an illegal packet and requesting retransmission is the same as that of the source data transmission device 1a. The operation different from that of the transmission data transmitting apparatus 1a is that, if the received packet is an expected sequence number, the received number is transmitted to the packet transmission control means 14 as a normal packet by the reception number recognition means 11; 1
4 is transmitted to the target data terminal 2b, but when the received packet does not have the expected sequence number, that is, when a lost packet occurs and a normal packet having a sequence number larger than the expected order is input, This packet is registered in the order queue storage means 15, and the packet transmission control means 1
4 is not transmitted to the data terminal 2b. In this case, the expected sequence number is not updated.

Therefore, the normal packets received after the lost packet are registered in the order queue storage unit 15 until the lost packet (expected sequence number) is retransmitted. If a normal packet having the expected sequence number is received by the reception number recognizing means 11 by retransmission, the packet is transmitted to the packet transmission control means 1.
4 and, if packets in the following order are registered in the order queue storage means 15, these are transmitted from the packet transmission control means 14. That is, if the received packet is a sequence number expected to be received, the packet is passed to the packet transmission control means 14 and transmitted to the target data terminal 2.
b, and confirms whether or not a packet continuing in the order queue storage means 15 is registered. If registered, the packet transmission control means 14 sequentially transmits the packet to the target data terminal 2b. If the received packet is not the sequence number expected to be received, it is registered in the sequence queue storage means 15, and after receiving the packet having the expected sequence number, the packet is passed to the packet transmission control means 14, and Transmit to terminal 2b.

As described above, in this embodiment, without waiting for lost packets to be retransmitted as in the prior art,
Normal packets are sequentially transmitted to the next-stage data transmission device. By doing so, it is not necessary to wait for the complete transmission of a packet for each single link before starting the next transmission, thereby suppressing transmission delay in a cascade link formed by connecting a plurality of links. .

In the above description, the expected sequence number is updated only when a packet in the expected order is transmitted, and the expected sequence number is not updated even when a normal packet having a higher sequence number is transmitted. Although the method for determining whether a retransmission request is necessary based on this is shown, the determination of the necessity of a retransmission request is not limited to this method. If possible. For example, even if the expected sequence number is always updated when a normal packet is transmitted, the packet loss at the preceding stage can be detected.

Embodiment 2 FIG. In the first embodiment, the case where the normal packet determined to be normal by the invalid packet detecting means 10 is simply transmitted is described. In this case, if there is a lost packet, the data transmission device transmits a retransmission request and the next packet is transmitted. Even in the identification number recognition means 11 of the data transmission device, the sequence numbers are missing.
A retransmission request is sent for the same sequence number.
In the second embodiment, the data transmission apparatus that has transmitted the retransmission request notifies the next data transmission apparatus that the retransmission request for the packet has been completed to the next stage, thereby suppressing such retransmission request duplication. Show what can be done.

FIG. 3 is a diagram showing the configuration of a data transmission apparatus according to this embodiment. 10 to 15 are the same as those in FIG. 17 generates a packet including the identification information of the illegal packet detected by the identification number recognizing means 11 and the retransmission request information indicating that the retransmission request for the illegal packet has been transmitted as a dummy packet. And a dummy packet generation unit as a retransmission requested information packet control unit that sends the packet transmission control unit 14 a normal packet as a normal packet. Reference numeral 18 denotes a dummy packet detecting means for detecting whether the normal packet output by the identification number recognizing means 11 is a dummy packet, and 19 denotes an identification number of the dummy packet detected by the dummy packet detecting means 18. This is a dummy packet identification number storage means for storing.

In the second embodiment, the operations of detecting an illegal packet, requesting retransmission, and transmitting a normal packet are the same as those of the data transmission device of the first embodiment. In the second embodiment, the sequence number of the packet lost in the preceding link is stored in the packet transmission information storage means 12 by the identification number recognizing means 11, and the retransmission request packet sending means 13 makes a retransmission request to the preceding stage and is lost. The packet sequence number is notified to the dummy packet generation means 17. The dummy packet generation unit 17 generates a packet indicating that the packet is dummy as retransmission requested information, and inputs the packet to the packet transmission control unit 14 as a dummy packet having the sequence number of the notified lost packet. The packet transmission control means 14 transmits the input dummy packet as a normal packet to the next-stage data transmission device.

Therefore, the data transmission device that has received the dummy packet knows that the packet is a packet for which retransmission has been requested.

In the data transmission apparatus receiving the dummy packet, the identification number recognizing means 11 detects and discards the illegal packet by the illegal packet detecting means 10 as described above. Even if it is a dummy packet, a normal packet is sent to the identification number recognizing means 11 to check the transmission sequence number and to determine whether the packet has the sequence number expected to be received. In the identification number recognizing unit 11, the normal packet is sent to the dummy packet detecting unit 18 if the sequence number is expected to be received without discrimination between a packet having valid information and a dummy packet.

The dummy packet detecting means 18 detects whether the input packet is a packet having valid information or a dummy packet, and the packet having valid information is sent to the packet transmission control means 14 as a normal packet. It is transmitted to the data transmission device of the stage. In the case of a dummy packet, the sequence number is stored in the dummy packet identification number storage means 19 for storing the sequence number received as a dummy packet, and the dummy packet is passed to the packet transmission control means 14 and is transmitted to the next stage as a dummy packet. Transmit to the data transmission device. The packet transmission information storage means 12
With the sequence number stored as the lost packet
When a normal packet is received, the retransmission packet from the previous stage is
The packet transmission information storage unit 12 recognizes the
Delete the sequence number and replace this received packet with a dummy packet.
It passes to the detecting means 18 and recognizes that it is not a dummy packet.
After that, the packet is passed to the packet transmission control means 14 and
-Sequence number similar to the sequence number sent as a packet
And send it as a normal packet.

As described above, since the packet for which the retransmission request has been completed in the preceding stage can be identified by the dummy packet, the next data transmission device does not request the same packet to be retransmitted. That is, when the identification number recognition unit 11 detects a missing sequence number, the corresponding sequence number is stored in the packet transmission information storage unit 12, and a retransmission request packet transmission unit 13 requests a retransmission of the lost packet. Since the requested packet is received as a normal dummy packet, a missing sequence number is not detected at this time. Therefore, here, retransmission is not requested for a packet that has been detected before the preceding data transmission device and has been normally received as a dummy packet, and a loss has been detected on the immediately preceding link between the preceding data transmission device and the own data transmission device. Only the retransmitted packet is requested.

On the other hand, when the dummy packet detecting means 18 receives a normal packet having the sequence number stored as a dummy packet in the dummy packet identification number storing means 19, it is not discarded as a duplicated received packet, Recognizing that the packet is a retransmission packet that replaces the dummy packet from the data transmission device, deletes the sequence number from the dummy packet identification number storage unit 19, sends the packet to the packet transmission control unit 14, and transmits the packet transmitted as the dummy packet. A sequence number similar to the number is added and the packet is transmitted as a normal packet to the next-stage data transmission device.

The operation in the outgoing data transmission device 1a and the relay data transmission devices 1b and 1c has been described above. Next, the operation in the destination data transmission device 1d will be described. Here, in order to finally output the packet to the data terminal 2b, it is necessary to rearrange the packet order correctly and to transmit the packet to the data terminal 2b after a series of packets are prepared. Works. In the destination data transmission device 1d, the operation of detecting an illegal packet and requesting retransmission is the same as that of the source data transmission device 1a.

A packet having valid information and a dummy packet are not distinguished by the identification number recognizing means 11.
Hand over to 18 . The packet having valid information is passed to the packet transmission control means 14 as a normal packet and transmitted to the target data terminal 2b. The dummy packet is stored in the dummy packet identification number storage means 19 for storing the received sequence number and discarded.

The packet transmission in the identification number recognizing means 11 is performed.
When a normal packet having a sequence number stored as a lost packet in the transmission information storage unit 12 is received, the sequence number is deleted from the packet transmission information storage unit 12 as a retransmission packet.

When a normal packet having the sequence number stored in the dummy packet identification number storage means 19 is received, the packet is not discarded as a duplicate received packet, but is a retransmitted packet replacing the dummy packet from the preceding data transmission apparatus. If there is, the sequence number is deleted from the dummy packet identification number storage means 19. If the packet is the sequence number expected to be received, the packet is passed to the packet transmission control means 14 and transmitted to the target data terminal 2b, and it is confirmed whether or not a packet to be continued in the sequence queue storage means 15 is registered. If they are registered, the packet transmission control means 14 sequentially transmits them to the target data terminal 2b. If the received sequence number is not the expected sequence number, the packet is registered in the sequence queue storage means 15 and after receiving the packet having the expected sequence number, the packet transmission control means 1
4 and transmitted to the target data terminal 2b.

FIG. 4 shows a conventional data link protocol from a source data transmission device 20a to a destination data transmission device 20d via relay data transmission devices 20b and 20c.
FIG. 9 is a sequence diagram of packet data transmission showing an example of transmitting one packet data. The first packet is normally transmitted from the originating data transmission device 20a to the relay data transmission device 20b as the information packet 21-a, and is transmitted from the relay data transmission device 20b to the relay data transmission device 20c. , And is normally transmitted as an information packet 23-a from the relay data transmission device 20c to the destination data transmission device 20d.
The second packet was transmitted as an information packet 21-b from the originating data transmission device 20a to the relay data transmission device 20b, but is lost due to a bit error.

Next, the third packet is normally transmitted from the originating data transmission device 20a to the relay data transmission device 20b as an information packet 21-c. The loss of the third packet (information packet 21-b) is recognized, and the transmission data transmission device 2
A selective retransmission request 21-f requesting retransmission of the information packet 21-b to 0a is transmitted. The received information packet 21-c is held in the relay data transmission device 20b until the information packet 21-b is normally received.

The fourth packet and the fifth packet are normally transmitted as information packets 21-d and 21-e from the source data transmission device 20a to the relay data transmission device 20b. Transmission device 20
Since the information packet 21-b expected at b is not received, it is suspended at 20b. On the other hand, the outgoing data transmission device 20a receives the selective retransmission request 21-f, and accordingly, the outgoing data transmission device 20a
The retransmission information packet 21-b 'is retransmitted for 0b.

The relay data transmission device 20b normally receives the second packet as the retransmission information packet 21-b ', and since this is an expected information packet, transmits the second packet to the relay data transmission device 20c. , Are normally transmitted as the information packet 22-b. In addition, this is performed from the relay data transmission device 20c to the destination data transmission device 20d.
Is normally transmitted as an information packet 23-b.

On the other hand, the relay data transmission apparatus 20b subsequently transmits the held third packet to the relay data transmission apparatus 20c as the information packet 22-c, but is lost due to a bit error. Next, the held fourth packet is transmitted from the relay data transmission device 20b to the relay data transmission device 20c by the information packet 22-d.
And the relay data transmission device 20c recognizes the disappearance of the information packet 22-c from the transmission sequence number.

The selective retransmission request 22-f for requesting the retransmission of the information packet 22-c is transmitted from the relay data transmitting apparatus 20c to the relay data transmitting apparatus 20b, and the received information packet 22-d is changed to the information packet 22. -C is held in the relay data transmission device 20c until it is received normally. The fifth packet held by the relay data transmission device 20b is normally transmitted as an information packet 22-e to the relay data transmission device 20c, but the information expected next by the relay data transmission device 20c. Packet 22
-C is suspended at 20c because it could not be received. The relay data transmission device 20b receives the selective retransmission request 22-f, whereby the retransmission information packet 22-f is transmitted from the relay data transmission device 20b to the relay data transmission device 20c.
Resend c '.

The relay data transmission device 20c normally receives the third packet from the relay data transmission device 20b as the retransmission information packet 22-c ', which is transmitted from the relay data transmission device 20c to the destination data transmission device 20d. Normally transmitted as information packet 23-c. The relay data transmission device 20c subsequently transfers the fourth packet and the fifth packet, which have been held, to the relay data transmission device 20c.
d as information packets 23-d and 23-e, and the information packet 23-e is transmitted to the destination data transmission device 20.
At the timing received at d, transmission of data of all five packets is completed. As described above, in each data transmission device, since five packets are completely transmitted, a delay occurs due to the suspension of the packet, and in this example, three relay data transmission devices 20b and three relay data transmission devices are used. 20c results in a transmission delay of two transmissions.

On the other hand, FIG. 5 is a sequence diagram of packet data transmission showing an example of transmitting five packet data from the originating data transmission device 1a to the destination data transmission device 1d according to this embodiment. The first packet is an information packet 2 transmitted from the data transmission device 1a to the data transmission device 1b.
4-a, transmitted normally from the data transmission device 1b to the data transmission device 1c as an information packet 25-a, and transmitted from the data transmission device 1c to the data transmission device 1d as an information packet 26-a. Transmitted normally. The second packet was transmitted as an information packet 24-b from the data transmission device 1a to the data transmission device 1b, but is lost due to a bit error.

Next, the third packet is transmitted from the data transmission device 1a to the data transmission device 1b by the information packet 24.
-C, and the data transmission device 1b recognizes the loss of the information packet 24-b from the transmission sequence number. Then, a selective retransmission request 24-f requesting retransmission of the information packet 24-b is transmitted from the data transmission device 1b to the data transmission device 1a, and a dummy information packet is substituted for the simultaneously lost information packet 24-b. 25-b is generated and transmitted normally from the data transmission device 1b to the data transmission device 1c. Further, the data is transmitted as a dummy information packet 26-b from the data transmission device 1c to the data transmission device 1d normally. The data transmission device 1b transmits the received third information packet 24-c as the information packet 25-c without waiting for the reception of the lost information packet 24-b following the transmission of the dummy information packet 25-b. .

The fourth packet and the fifth packet are normally transmitted from the data transmission device 1a to the data transmission device 1b as information packets 24-d and 24-e. The data packets are transmitted as information packets 25-d and 25-e from the data transmission device 1b to the data transmission device 1c without waiting for reception.
The data transmission device 1a receives the selective retransmission request 24-f, and retransmits the retransmission information packet 24-b 'from the data transmission device 1a to the data transmission device 1b.
The data transmission device 1b transmits the third packet as the information packet 25-c, but is lost due to a bit error. The next fourth packet is normally transmitted from the data transmission device 1b to the data transmission device 1c as an information packet 25-d, and the data transmission device 1c recognizes the disappearance of the information packet 25-c from its transmission sequence number. Is done.

Therefore, a selective retransmission request 25-f for requesting retransmission of the information packet 25-c is transmitted from the data transmission apparatus 1c to the data transmission apparatus 1b, and dummy information is replaced instead of the lost 25-c. packet 26-c is generated, the data transmission device 1d from the data transmission device 1c
Successfully transmitted to In the data transmission device 1c , following the transmission of the dummy information packet 26-c, the lost 25-c
The fourth information packet 25-d received is transmitted as the information packet 26-d without waiting for reception of the data packet, and is normally received by the data transmission device 1d.

The fifth packet is the data transmission device 1b
Sends an information packet 25-e to the data transmission apparatus 1c.
Information packet 25-c transmitted normally as
Is transmitted as an information packet 26-e from the data transmission device 1c to the data transmission device 1d without waiting for the reception of the information packet 26-e. On the other hand, the data transmission device 1b transmits the second packet from the data transmission device 1a to the retransmission information packet 24.
-B ', which is normally received as the data transmission device 1b
To the data transmission apparatus 1c from the retransmission information packet 25
-B 'is normally transmitted, and the retransmission information packet 26- is transmitted from the data transmission device 1c to the data transmission device 1d.
Normally transmitted as b '.

The data transmission device 1b sends a selective retransmission request 25
-F is received, the retransmission information packet 25-c 'is retransmitted from the data transmission device 1b to the data transmission device 1c, and the retransmission information packet 26-c' is normally transmitted from the data transmission device 1c to the data transmission device 1d. Is transmitted to At this time, the data transmission device 1d has received the fourth packet and the fifth packet in which no transmission error occurred on the way, and at the timing when the retransmission information packet 26-c 'was successfully received, all the five packets were received. Data transmission is completed. As described above, since each normally received packet is sequentially sent to the next data transmission device, transmission delay can be suppressed as compared with the conventional case of FIG.

Embodiment 3 FIG. In the above second embodiment, sending a dummy packet as a normal packet indicates sending retransmission requested information,
If this is normally received, the retransmission request can be prevented from being issued by the identification number recognition means 11, but the method of transmitting the retransmission requested information is not limited to this. For example, the retransmission request completion information may be added to the packet and read by the identification number recognizing means 11 to make a determination.

[0057] Figure 6, in such a case, a block diagram of a data transmission apparatus according to another embodiment of the present invention, 10
And 12 to 15 are the same as those in the above embodiment. 3
Reference numeral 4 denotes a notification lost packet detecting means as an invalid packet information detecting means, reference numeral 35 denotes a notification lost packet storage means, and reference numeral 36 denotes a notification lost packet adding means as an invalid packet information adding means.

Also in the third embodiment, the operations of detecting an illegal packet, requesting retransmission, and transmitting a normal packet are the same as those of the data transmission apparatus of the first embodiment. When the identification number recognition means 11 receives a normal packet,
The sequence number of the packet lost in the preceding link is detected, but the sequence number of the lost packet is recorded in the packet transmission information.
It is stored in the storage unit 12 .

The notification lost packet adding means 36 adds the sequence number of the lost packet stored in the notification lost packet storage 35 as invalid packet information to the communication control information portion of the normally received packet and the packet transmission information.
The sequence number of the lost packet in the immediately preceding link stored in the transmission information storage unit 12 is added. Then, the packet is passed to the packet transmission control means 14 without waiting for the reception of the lost packet.
The data is transmitted to the next-stage data transmission device.

In the identification number recognizing means 11 of the data transmission apparatus which has received the packet, if the sequence number is expected to be received, the received packet is passed to the notification lost packet adding means 36, and the received packet is stored in the notification lost packet storage means 35. If the lost packet to be notified is registered, the sequence number of the lost packet at that time stored in the notification lost packet storage means 35 as lost packet information, and the packet
The packet transmission control unit 1 adds the sequence number of the lost packet in the immediately preceding link stored in the transmission information storage unit 12.
4 and transmitted to the next-stage data transmission device.

On the other hand, when the identification number recognition means 11 receives a normal packet having the sequence number stored as a lost packet in the packet transmission information storage means 12, it recognizes it as a retransmission packet from the previous stage and
The sequence number is deleted from the transmission information storage unit 12, the sequence number is also deleted from the notification lost packet storage unit 35, the received packet is passed to the notification lost packet addition unit 36, and the notification lost packet storage unit 35 is notified. If a lost packet to be registered is registered, the sequence number of the lost packet at that time stored in the notification lost packet storage unit 35 as communication control information of the packet, and stored in the packet transmission information storage unit 12 The sequence number of the lost packet on the immediately preceding link is added, and the packet is passed to the packet transmission control means 14 without waiting for the reception of the lost packet, and is transmitted to the next-stage data transmission device.

When the identification number recognition means 11 detects a missing sequence number, it passes it to the notification lost packet detection means 34, refers to the lost packet information of the received packet, and has already been detected by the preceding data transmission apparatus. The sequence number of the lost packet is detected and stored in the notification lost packet storage means 35. The notified lost packet is assumed to be pseudo-received on the immediately preceding link. Moreover,
The identification number recognizing means 11 detects a packet lost on the immediately preceding link between the preceding data transmission apparatus and the own data transmission apparatus, and if there is a lost packet between the preceding data transmission apparatus and the packet transmission information, The corresponding sequence number is stored in the storage means 12, a retransmission request packet is generated in the retransmission request packet transmitting means 13, and a retransmission request for the lost packet is made to the preceding apparatus. (Here, the notification lost packet detecting means 34 functions as the immediately preceding incorrect packet detecting means.)

That is, if the identification number recognizing means 11 detects only a missing sequence number, it is determined whether the packets from the expected sequence number to the sequence number immediately before the normally received packet have been lost in the immediately preceding link. It is not possible to judge whether the packet has been lost earlier and a retransmission request has already been made.However, by sending the above illegal packet information as additional information of a normal packet, whether the packet with the missing sequence number has been lost on the previous link. Before that, it can be determined whether the data has been lost and a retransmission request has already been made. As a result, a retransmission request can be made only for the packet that has been lost immediately before, and duplication of the retransmission request can be suppressed. The above are the outgoing data transmission device 1a and the relay data transmission device 1b,
Having described the operation in 1c, the operation in the destination data transmission device 1d will now be described. Here, in order to finally output the packet to the data terminal 2b, it is necessary to rearrange the packet order correctly and to transmit the packet to the data terminal 2b after a series of packets are prepared. Works.

In the destination data transmission device 1d, the operation of detecting an illegal packet and requesting retransmission is the same as that of the source data transmission device 1a. When a normal packet having the sequence number stored in the notification lost packet storage means 35 is received, it is recognized as a retransmission packet already recognized by the preceding data transmission device, and the notification lost packet storage means 35 is recognized.
From the sequence number. If the received packet is a sequence number expected to be received, it is passed to the packet transmission control means 14 and transmitted to the target data terminal 2b, and it is checked whether a packet to be continued in the sequence queue storage means 15 is registered. If they are registered, the packet transmission control means 14 sequentially transmits them to the target data terminal 2b. If the received packet is not the sequence number expected to be received, it is registered in the sequence queue storage means 15, and after receiving the packet having the expected sequence number, the packet is passed to the packet transmission control means 14, and Transmit to the data terminal 2b.

Embodiment 4 FIG. 7 is a configuration diagram of a data transmission device according to the fourth embodiment. 10 to 19 are the same as those in FIG. 3 described in the second embodiment. Reference numeral 50 denotes an acknowledgment transmission timer, and reference numeral 51 denotes acknowledgment transmission means for transmitting the acknowledgment information to the transmission source when the retransmission request completion information is received. FIG. 8 is a format diagram showing an example of the acknowledgment information format in this embodiment, wherein 52 is a cascade link acknowledgment frame, 53 is an expected reception sequence number, and 54 is an immediately preceding link reception expected sequence number. This cascade link acknowledgment frame 52 has an expected reception sequence number 53 indicating the transmission sequence number of the packet next to the packet whose reception has been completed.
It is assumed that the reception is considered to be completed if the dummy packet from the data transmission apparatus at the preceding stage is also normally received, and is configured by the immediately preceding link reception expected sequence number 54 indicating the expected sequence number of reception at the immediately preceding link. Is done.

The embodiment of the data transmission apparatus based on the transmission method in the cascade link from the source data transmission apparatus 1a to the destination data transmission apparatus 1d via the relay data transmission apparatuses 1b and 1c has been described above. By applying the cascade link acknowledgment frame in these, the delivery information (expected reception sequence number 53) of the packet having the valid information can be notified to the data transmission device in each preceding stage, thereby enabling the data transmission processing in each preceding stage. Can be terminated. That is, since the normally transmitted packet is known, it is possible to open the memory for storing and holding the packet in the order before the packet or confirm the end of the transmission.

Further, by notifying the acknowledgment information (prior link expected reception sequence number 54) focused on the upstream link to each upstream data transmission apparatus, the retransmission control for each link constituting the cascade link can be performed smoothly. According to this, it is possible to reduce the end-to-end data transmission delay by transmitting a normally received packet to the next-stage data transmission device at an earlier timing, and at the same time, to improve the data throughput efficiency of the transmission path. Can be improved.

In the packet received by the relay data transmission device 1b, 1c or the destination data transmission device 1d, an illegal packet having a bit error is detected by the illegal packet detecting means 10 using a frame check sequence added to the packet. And discard. The packet having no bit error is passed to the identification sequence number recognizing means 11, which checks the transmission sequence number of the received packet and checks whether the packet has the sequence number expected to be received. A packet having valid information in the identification number recognizing means 11;
Without discrimination between dummy packets, if the sequence number is expected to be received, the packet is passed to the dummy packet detecting means 18 , and a packet having valid information is passed to the packet transmission control means 14 as a normal packet.

At this time, if the packet has valid information, it is notified to the preceding data transmission apparatus that the expected reception sequence number of the packet having valid information not including the dummy packet has been updated. In order to notify the data transmission device, first, the activation state of the acknowledgment transmission timer 50 is confirmed, and if not activated, the timer 50 is activated. If the packet is a dummy packet, it notifies the preceding data transmission apparatus to notify the preceding data transmission apparatus that the expected reception sequence number of the packet including the dummy packet focused on the preceding link has been updated. In order to do so, first, the activation state of the delivery confirmation transmission timer 50 is confirmed, and if it has not been activated, the timer 50 is activated.

If the acknowledgment timer 50 times out, the acknowledgment information transmitting means 51 and the immediately preceding link expected sequence number 54 stored in the identification number recognizing means 11 and the expected reception number stored in the dummy packet detecting means 18 are used. The cascade link acknowledgment frame 52 is generated with reference to the sequence number 53 and transmitted to the preceding data transmission device. If any data packet to be transmitted to the preceding data transmission device, such as a retransmission request packet, occurs while the delivery confirmation timer 50 is running, the delivery confirmation timer 50 is stopped, and the immediately preceding link reception expectation is set as communication control information of the packet. Sequence number 54 and expected reception sequence number 5
3 may be added and transmitted to the preceding data transmission apparatus. Note that the same effect can be obtained by transmitting the immediately preceding link expected sequence number 54 and the expected sequence number 53 to the data transmission apparatus according to the third embodiment.

Embodiment 5 FIG. FIG. 9 is a configuration diagram of a data transmission device according to the fifth embodiment. 10 to 19 are the same as those in FIG. 3 described in the second embodiment. Reference numeral 60 denotes a packet retransmission clock.
1 is a packet retransmission control means, and 62 is a retransmission request / delivery confirmation receiving means.

In the case of the above-described embodiment, the packet requested to be retransmitted is retransmitted from the previous stage and transmitted to the next stage. If the packet including the lost packet information is further lost in the link to the next data transmission device, a retransmission request for the same packet is made from the next data transmission device. Therefore, even if a retransmission request is received from the next stage for the same packet after transmitting the retransmission packet from the previous stage to the next stage, the retransmission packet from the previous stage has already been transmitted to the next stage, so Therefore, if retransmission is performed for a retransmission request for a retransmission packet from the next stage, retransmission may be duplicated.

In this embodiment, the packet retransmission clock 60
The transmission time of a retransmission packet is stored by packet retransmission control means having a function as a retransmission time storage means based on the time of retransmission, and when the retransmission request for this packet is received, the retransmission request time and the stored retransmission request time are stored. By judging the necessity of retransmission by comparing with the packet transmission time,
This is to prevent duplication of retransmission. FIG. 10 is a sequence diagram showing an example of transmitting packet data from the originating data transmission device 1a to the relay data transmission device 1c by the data transmission device of this embodiment.

The first packet is the outgoing data transmission device 1
a to the relay data transmission device 1b from the information packet 6
Although transmitted as 5-a, it is lost due to a bit error. Next, the second packet is transmitted from the source data transmission device 1a to the relay data transmission device 1b by the information packet 65-.
b, and the relay data transmission apparatus 1b recognizes the disappearance of the information packet 65-a from the transmission sequence number. Then, a selective retransmission request 65-c requesting retransmission of the information packet 65-a is transmitted from the relay data transmission device 1b to the originating data transmission device 1a, and a dummy packet is replaced with the dummy packet instead of the lost information packet 65-a. The information packet 66-a is generated, and the relay data transmission device 1
b to the relay data transmission device 1c, but is lost due to a bit error.

Subsequently, the relay data transmitting apparatus 1b converts the received second information packet 65-b into the information packet 66-b without waiting for the reception of the lost information packet 65-a.
b and is normally received by the relay data transmission device 1c. The originating data transmission device 1a is a relay data transmission device 1b
Receives the selective retransmission request 65-c from the source data transmission device 1a and retransmits it as a retransmission information packet 65-a 'to the relay data transmission device 1b, and reads the current time from the packet retransmission clock 60, It is registered as a retransmission time corresponding to this retransmission information packet 65-a '.

The retransmission information packet 65-a 'is normally received by the relay data transmission device 1b. Previous information packet 6
Although the dummy information packet 66-a has been transmitted due to the loss of 5-a, the retransmission information packet 66-a 'is generated in the packet retransmission control means 61 as a packet having valid information, and retransmitted by the packet transmission control means 14. .
At this time, the current time is read from the packet retransmission clock 60 and stored as the retransmission time corresponding to the retransmission information packet 66-a '. Since the relay data transmission device 1c has received the information packet 66-b without receiving the dummy information packet 66-a, it detects the disappearance of the information packet 66-a and selectively retransmits the information packet 66-a. Request 66-c is sent.

The relay data transmission device 1b reads the time when the selective retransmission request 66-c is received from the relay data transmission device 1c from the packet retransmission clock 60, and stores this time and the time stored in the packet retransmission control means 61. The retransmission information packet 66-a 'is compared with the retransmission time.

At this time, the difference between the retransmission time of the retransmission information packet 66-a 'and the reception time of the selective retransmission request 66-c is a fixed time (substantially the packet transmission time from the relay data transmission device 1b to the relay data transmission device 1c). If the time has elapsed, the retransmission information packet 66-a 'should have arrived at the time of transmission of the retransmission request packet 66-c in the relay data transmission device 1c, and the retransmission request has been received nonetheless. This means that the retransmission request packet 66-
c is recognized as a retransmission request due to the disappearance of the retransmission information packet 66-a ', and retransmits the retransmission information packet 66-a ".

At this time, the retransmission time of 66-a 'and 6
If the difference between the reception times of 6-c has passed less than a certain time (the packet transmission time from approximately 1b to 1c), the retransmission request packet 66-
At the time of transmission c, the retransmission information packet 66-a 'has not arrived, and the retransmission request packet 66-c and the retransmission information packet 66-a' have been transmitted during the transmission time of the relay data transmission device 1b and the relay data transmission device 1c. Is likely to have been received in a collision, and retransmission will result in duplicate retransmission, so that retransmission of the retransmission information packet 66-a ″ is not performed.

In a circuit having a large data transmission delay,
As described above, when a packet is retransmitted due to reception of a retransmission request packet, or when a packet is retransmitted due to reception of an acknowledgment packet or the like, the previous retransmission time is compared with the time at which the retransmission request was generated. It is possible to prevent retransmission, improve the use efficiency of a line that shares a transmission channel for a plurality of communications, such as a satellite line or a LAN, and reduce the processing load of the data transmission device.

The same effect can be obtained by applying the retransmission control based on the retransmission time to the data transmission apparatus shown in the third embodiment. The same effect can be obtained by applying the present invention to a data transmission device using a conventional data link protocol with a single link having a large data transmission delay.

Embodiment 6 FIG. FIG. 11 is a configuration diagram of a data transmission device according to the fifth embodiment, and 10 to 19 are the same as those in FIG. 3 described in the second embodiment. 70 is a retransmission request packet transmission clock, 71 is a packet retransmission control unit, and 72 is a retransmission request / delivery confirmation receiving unit. In a case like the one shown in the above-mentioned embodiment, the packet requested to be retransmitted will be retransmitted from the previous stage sometime, and will be transmitted to the next stage.
If the dummy packet or the packet containing the lost packet information sent earlier is further lost in the link to the next data transmission device, a retransmission request for the same packet is made from the next data transmission device. You. Therefore, if the retransmission request packet from the next stage comes shortly before the retransmission packet from the previous stage is sent, the dummy packet will be retransmitted because there is no normal data at that time. Immediately after receiving the normal packet retransmitted from the previous stage, it will be sent to the next stage,
There is a possibility that the transmission of the dummy packet transmitted earlier and the processing at the next stage are wasted.

In this embodiment, based on the time of the retransmission request packet transmission clock 70, the retransmission request packet transmitting means having a function as a retransmission request time storage means sets the transmission time of the retransmission request packet to the preceding stage. Remember, from the next stage
When the retransmission request packet corresponding to the retransmission request comes, by comparing the arrival time of the retransmission request packet with the stored retransmission request packet transmission time to determine whether or not the dummy packet needs to be retransmitted, the above waste is eliminated. It is to prevent.

FIG. 12 shows a case where the data transmission apparatus according to the present embodiment transmits data from the transmission data transmission apparatus 1a to the relay data transmission apparatus 1a.
FIG. 13 is a sequence diagram illustrating an example of transmitting packet data to a packet c.

The first packet is the outgoing data transmission device 1
a to the relay data transmission device 1b
Although transmitted as 5-a, it is lost due to a bit error.

[0086] Next is normally transmitted as information packet 75-b to the second second packet originating the data transmission device 1a from the relay data transmission device 1b, the information packet 75 from the transmission sequence number in the relay data transmission device 1b −
The disappearance of a is recognized. As a result, a selective retransmission request 75-c for requesting retransmission of the information packet 75-a is transmitted from the relay data transmission device 1b to the originating data transmission device 1a, and instead of the information packet 75- a that has been lost at the same time. A dummy information packet 76-a is generated and transmitted from the relay data transmission device 1b to the relay data transmission device 1c.
At this time, the packet retransmission control means 71 refers to the packet retransmission request transmission clock 70, and stores the time at which the selective retransmission request 75-c was transmitted corresponding to the transmitted dummy information packet 76-a. This dummy information packet 76-a is lost due to a bit error. Subsequently, the relay data transmission device 1b transmits the second information packet 75-b received without waiting for the reception of the lost information packet 75-a as the information packet 76-b, and normally receives it at the relay data transmission device 1c. Is done.

On the other hand, the outgoing data transmitting apparatus 1a receives the selective retransmission request 75-c from the relay data transmitting apparatus 1b, and the information packet 75-a requested to be retransmitted is not a dummy packet. the retransmission information packet 75-a 'send <br/> the relay data transmission device 1b from. In addition, the relay data transmission device 1 c
Since the information packet 76-b is received without receiving the information packet 76-a, the selective retransmission request 76 for detecting the disappearance of the information packet 76-a and requesting the information packet 76-a to be retransmitted is received.
Send -c. The relay data transmission device 1b receives the selective retransmission request 76-c, and
, It is recognized that 76-a requested to be retransmitted is a dummy packet. And the time that was memorized,
That is, the time at which the selective retransmission request 75-c requesting the retransmission of the original information packet 75-a is transmitted, and the retransmission request packet transmission clock 70 at which the selective retransmission request 76-c is received.
Is compared with the current time.

At this time, the difference between the transmission time of the selective retransmission request 75-c and the reception time of the selective retransmission request 76-c is a fixed time (substantially the packet transmission time from the originating data transmission device 1a to the relay data transmission device 1b). Twice: outgoing data transmission device 1
a), the packet is transmitted from the transmission data transmission device 1a to the relay data transmission device 1b for less than the time required to return a response).
An information packet 75 having valid information in response to c.
a 'should be able to be received, and it may be sent to the relay data transmission device 1c.
The dummy packet 76-a 'is not retransmitted as a response to c.

The difference between the transmission time of the selective retransmission request 75-c and the reception time of the selective retransmission request 76-c is a fixed time (substantially from the originating data transmission device 1a to the relay data transmission device 1-c).
twice as long as the packet transmission time to packet b: outgoing data transmission device 1a
If the time has elapsed after transmitting a packet to the relay data transmission device 1b and returning a response), the retransmission request packet 75-c transmitted from the relay data transmission device 1b or the response from the originating data transmission device 1a is transmitted. There is a high possibility that the retransmission information packet 75-a 'has been lost, and the dummy information packet is retransmitted as a response to the retransmission request packet 76-c as 76-a'.

When a dummy packet as shown in the second embodiment is introduced on a line having a large data transmission delay,
Receiving a packet having valid information immediately after retransmitting the dummy packet may invalidate the retransmission of the dummy packet. According to this embodiment, the transmission of the invalid dummy packet is performed. Can be prevented, the use efficiency of a line sharing a transmission medium such as a satellite line or a LAN with a plurality of channels can be improved, and the processing load on the data transmission device can be reduced. The same effect can be obtained even if this is applied to a device other than the second embodiment.

Note that all of the above embodiments may be configured by hardware or may be realized by software.

[0092]

As described above, in the data transmission apparatus according to the present invention, when packet data is transmitted via a plurality of data links including a line having a large transmission error rate and a line having a large data transmission delay, an -Packet data transmission delay between end data terminals can be reduced, and data throughput efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a network configuration diagram showing an embodiment of a network using a data transmission device of the present invention.

FIG. 2 is a configuration diagram of a data transmission device according to the embodiment of the present invention.

FIG. 3 is a configuration diagram of a data transmission device according to the embodiment of the present invention.

FIG. 4 is a sequence diagram showing an example of packet data transmission according to a conventional data link protocol.

FIG. 5 is a sequence diagram showing an example of packet data transmission according to the embodiment of the present invention.

FIG. 6 is a configuration diagram of a data transmission device according to an embodiment of the present invention.

FIG. 7 is a configuration diagram of a data transmission device according to an embodiment of the present invention.

FIG. 8 is a format diagram showing an example of a delivery confirmation information format according to the embodiment of the present invention.

FIG. 9 is a configuration diagram of a data transmission device according to an embodiment of the present invention.

FIG. 10 is a sequence diagram showing an example of packet data transmission according to the embodiment of the present invention.

FIG. 11 is a configuration diagram of a data transmission device according to an embodiment of the present invention.

FIG. 12 is a sequence diagram showing an example of packet data transmission according to the embodiment of the present invention.

FIG. 13 is a configuration diagram of a conventional data transmission device.

[Explanation of symbols]

1a Outgoing data transmission device 1b, 1c Relay data transmission device 1d Incoming data transmission device 10 Illegal packet detection means 11 Identification number recognition means 12 Packet transmission information storage means 13 Retransmission request packet transmission means 14 Packet transmission control means 15 Order queue storage means 17 Dummy packet generation means 18 Dummy packet detection means 19 Dummy packet identification number storage means 34 Notification lost packet detection means 35 Notification lost packet storage means 36 Notification lost packet addition means 51 Delivery confirmation transmission means 61 Packet retransmission control means 71 Packet retransmission control means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-166746 (JP, A) JP-A-57-53162 (JP, A) JP-A-58-40943 (JP, A) 199646 (JP, A) JP-A-4-243344 (JP, A) IEICE Technical Report RC S95-138 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/54 H04L 29 / 08 H04L 1/00

Claims (9)

(57) [Claims] 1. A method for receiving a received packet, comprising the steps of:
Normal / invalid judgment is made in order, invalid packets are discarded, and normal
Packet judging means for outputting a packet, and a packet included in a normal packet output from the packet judging means.
The discarded packet based on the identification information of the
Identification number recognition means for detecting an identification number of a positive packet;
A retransmission request packet requesting retransmission of the invalid packet
Retransmission request packet generated and transmitted to the source data transmission equipment
Retransmission request means having a packet transmission means, and a normal packet output from the packet determination means,
The discarded illegal packet is retransmitted and received normally.
Without waiting until the destination data transmission device
Packet transmitting means for transmitting.
Data transmission device. 2. A dummy including identification information (corresponding to a number) of an invalid packet requested to be retransmitted by the retransmission request unit and retransmission requested information indicating that retransmission of the invalid packet has been requested.
2. The data transmission apparatus according to claim 1, further comprising a retransmission requested information packet control unit that generates a packet and outputs the dummy packet as a normal packet corresponding to the invalid packet to the packet transmission unit. 3. An illegal packet information adding means for adding the identification information of the illegal packet to the normal packet as illegal packet identification information and outputting the information to the packet transmitting means, and the illegal packet identification information added to the received normal packet. An illegal packet information detecting means for detecting, and, based on the invalid packet identification information detected by the invalid packet information detecting means, of the invalid packets determined by the packet determining means , 2. The data transmission apparatus according to claim 1, further comprising: immediately before detection, an unjust packet detecting unit for controlling the retransmission request packet transmitting unit to transmit the retransmission request for the immediately preceding invalid packet. 4. A dummy packet including the retransmission requested information.
When receiving the door, the data transmission apparatus according to claim 2, characterized in that a delivery confirmation transmitting means for transmitting the acknowledgment information of the dummy packet to the sender. 5. A retransmission time storage means for storing a retransmission packet transmission time, a retransmission time stored in the retransmission time storage means, and a time at which the retransmission request signal corresponding to the packet in which the retransmission time is stored is received. data transmission apparatus of claims 1, characterized in that a packet retransmission control means for determining a retransmission necessity of packets 4, wherein based on. 6. A retransmission request time storage means for storing a time at which a retransmission request signal is transmitted by the retransmission request means, a retransmission request time stored in the retransmission request time storage means, and a packet storing the retransmission request time. And a retransmission request information packet transmission control means for determining whether retransmission of the retransmission request information packet is required by the retransmission request information packet control means based on the time at which the retransmission request signal corresponding to the retransmission request signal is received. 3. The data transmission device according to claim 2, wherein: 7. The method according to claim 7 , wherein the received packet is
Normal / invalid judgment is made in order, invalid packets are discarded, and normal
A packet determining step of extracting a packet; and a normal packet extracted in the packet determining step.
Based on the identification information of the included packet, the discarded
Identification number recognition process for detecting the identification number of an illegal packet
And a retransmission request packet requesting retransmission of the
A retransmission request packet that generates a packet and sends it to the source data transmission device.
A retransmission requesting step including a packet transmitting step, and a normal packet output from the packet determining step.
The discarded illegal packet is retransmitted and received normally.
Without waiting until the destination data transmission device
Transmitting a packet.
Data transmission method. 8. A identity fraud packet the retransmission request, generates a dummy packet including the retransmission request completion information indicating a retransmission request already in this rogue packet, the Damipake
8. The data transmission method according to claim 7 , wherein the packet is transmitted as a normal packet corresponding to the illegal packet. 9. The method according to claim 7, further comprising: transmitting the identification information of the illegal packet to the normal packet as illegal packet identification information; transmitting the illegal packet identification information added to the received normal packet; 8. The data transmission method according to claim 7 , wherein, based on the information, the immediately preceding invalid packet which has become an invalid packet in the previous stage is detected from the invalid packets, and a request for retransmission of the immediately preceding invalid packet is made.