JPH05122286A - Communication protocol device with packet re-transmission function - Google Patents

Abstract

PURPOSE:To provide the communication protocol device with a re-transmission function in which the transmission reception efficiency of a packet is enhanced when a re-transmission request is received. CONSTITUTION:A transmission control section 13 implementing re-transmission control only a packet subject to re-transmission request is provided to a transmission protocol 1 and a packet tentative latch section 25 to latch tentatively a packet received correctly and a packet sequence re-configuration section 26 to rearrange the sequence of the correctly received packet and the re-transmitted packet are provided to a reception protocol 2 and all data are correctly sent/received by having only to re-transmit only packets sent/received incorrectly. Thus, the efficiency at the re-transmission is remarkably improved in the communication having a large transmission delay such as the communication between a ground equipment and a space equipment.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to communication protocols,
Particularly, it relates to a communication protocol having a packet retransmission function.

[0002]

2. Description of the Related Art Conventionally, as a communication protocol having a packet retransmission function, there are IEEE802.2 LLC type 2 or ISO8073 transport class 4. When there is a packet loss or packet abnormality, these communication protocols are designed to retransmit all packets after the abnormal or missing packet, even if they are transmitted normally including the abnormal or missing packet. , Guarantees the correctness and order of the packets to be communicated.

FIG. 2 is a functional block diagram of a conventional communication protocol having a packet retransmission function. The transmission side protocol 3 is transmitting a series of packets to the reception side protocol 4. The packet transmission unit 31 assigns a serial number to a series of packets to be transmitted and transmits the packets. The packet received by the packet receiving unit 41 is diagnosed by the packet loss / abnormality monitoring unit 43 for packet loss or packet abnormality, and if normal, it is passed to the packet storage unit 44 and stored therein.

When a packet loss or packet abnormality is found, the packet loss / abnormality monitoring unit 43 notifies the retransmission request message transmission unit 42 to transmit a message requesting the packet retransmission, and thereafter, the retransmission request is issued. All other packets received by the time the received packet is received are passed to the packet discard unit 45. The packet discard unit 45 discards the received packet.

The resend request message sending unit 42 sends a resend request message for the notified packet. The resend request message receiving unit 32 passes the received resend request message to the packet transmitting unit. Upon receiving the retransmission request message, the packet transmission unit 31 stops the packet transmission that has been performed until then, returns to the number of the packet for which the retransmission request has been received, and restarts the packet transmission from there.

[0006]

However, the above-mentioned conventional communication protocol device with a packet retransmission function is
When a packet loss or abnormality occurs, a retransmission request message for the packet arrives at the transmission side protocol in order to restart the packet transmission by returning to the lost or abnormal packet. In the meantime, the packet transmitted by the transmission side protocol and correctly received by the reception protocol is also retransmitted.

That is, since only one missing packet or abnormal packet is retransmitted, a plurality of other correctly transmitted and received packets are also retransmitted, which is a disadvantage of low efficiency. The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication protocol device with a packet retransmission function that can improve communication efficiency when reproducing a lost packet or an abnormal packet.

[0008]

In a communication protocol with a packet retransmitting function according to the present invention, a receiving side protocol monitors a missing or abnormal packet and a missing anomaly monitoring unit, and after detecting this missing anomaly, the packet is A packet primary holding unit that holds the received packet until it is retransmitted, and a packet order reconfiguring unit that rearranges all the packets in order by combining the retransmitted packet and the held packet. The transmitting side protocol temporarily suspends the transmission of the packet when receiving the retransmission request, transmits the packet for which the retransmission request is received, and then
It is characterized by having a transmission control unit for restarting packet transmission from the interrupted position.

[0009]

In the present invention, the packet primary holding unit of the receiving side protocol temporarily holds the normal packet transmitted after the resending request is issued, and the transmission control unit of the transmitting side protocol sends the packet from the interrupted point. To resume. And
The reordering unit of the receiving side protocol corrects the order by rearranging the retransmitted packet and the packet held in the primary holding unit, and rearranges them. Therefore, the transmission side protocol does not need to retransmit a packet that has been normally transmitted, so that communication efficiency is significantly improved.

[0010]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 is a functional block diagram of a communication protocol with a packet retransmission function according to an embodiment of the present invention. The sending side protocol 1 is sending a series of packets to the receiving side protocol 2. The transmission side protocol 1 includes a packet transmission unit 11, a retransmission request message reception unit 12 and a transmission control unit 13. The reception side protocol 2 includes a packet reception unit 21, a retransmission request message transmission unit 22, a packet loss / abnormality monitoring unit 23, a packet storage unit 24, a packet primary holding unit 25, and a packet order reconfiguration unit 26.

The difference between this embodiment and the above-mentioned conventional example is that the packet discarding unit 45 is eliminated and the transmission control unit 13, the packet primary holding unit 25, and the packet order reconstructing unit 26 are added. When the packet loss abnormality monitoring unit 23 detects a packet loss or abnormality, the packet primary retaining unit 25 temporarily retains a normal packet transmitted thereafter. Further, the packet order reconfiguring unit 26 combines the packets held in the packet primary holding unit 25 and the retransmitted packets and rearranges them in the correct order. On the other hand, in the transmission side protocol 1, when the transmission control unit 13 inputs a retransmission request from the retransmission request message receiving unit 12, the transmission control unit 13 interrupts the transmission,
Retransmit the requested protocol. Then, the transmission control unit 13 restarts the packet transmission from the interrupted location after the retransmission.

In the communication protocol device thus configured, the packet transmission / reception process in the normal state is the same as that of the conventional example. On the other hand, the processing is different when the packet loss is abnormal. It is assumed that an abnormality or loss of a certain packet occurs while the transmission side protocol 1 is transmitting a series of packets to the reception side protocol 2. Then, the packet loss abnormality monitoring unit 23 discovers the packet abnormality and the loss by checking the syntax and serial number of the received packet received from the packet receiving unit 21, and notifies the retransmission request message transmitting unit 22 of it. After that, the packet loss abnormality monitoring unit 23 passes the other normal packets received by the time of receiving the packet for which the retransmission request is received to the packet temporary holding unit 25, and the packet temporary holding unit 25 temporarily stores these normal packets.

The resend request message sending unit 22 sends a resend request message of the packet notified from the packet loss abnormality monitoring unit 23. The retransmission request message receiving unit 12 of the transmission side protocol 1 passes the received retransmission request message to the transmission control unit 13. Upon receiving the retransmission request message, the transmission control unit 13 instructs the packet transmission unit 11 to suspend the packet transmission and retransmit the packet for which the retransmission request is received.

Upon confirming that the packet has been retransmitted, the transmission control unit 13 designates the portion where the transmission is interrupted and instructs the packet transmission unit 11 to resume the transmission thereafter. When the packet loss abnormality monitoring unit 23 receives the packet for which the retransmission request has been issued, the packet loss abnormality monitoring unit 23 transfers the packet to the packet order reconfiguration unit 26. The packet order reconstructing unit 26 combines the packets held in the packet temporary holding unit 25 and the packets received from the packet loss abnormality monitoring unit 23, rearranges the packets correctly in the numerical order, and then It is passed to the packet storage unit 24. After that, the packet loss abnormality monitoring unit 23 passes the normally received packet to the packet storage unit 24.

[0016]

As described above in detail, according to the present invention, when a packet loss or abnormality is found, in the transmitting side protocol, only the packet having the loss or abnormality is retransmitted, and in the receiving side protocol. Since the correctly received protocol is temporarily stored and reconfigured in combination with the retransmitted packet in order, the communication efficiency can be improved without discarding the correctly transmitted and received packets during the retransmission process. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a communication protocol device with a packet retransmission function according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional communication protocol device with a packet retransmission function.

[Explanation of symbols]

 1, 3; transmission side protocol 2, 4; reception side protocol 11, 31; packet transmission unit 21, 41; packet reception unit 12, 32; retransmission request message reception unit 22, 42; retransmission request message transmission unit 23, 43; Packet loss abnormality monitoring unit 24, 44; packet storage unit 13; transmission control unit 25; packet temporary holding unit 26; packet order reconfiguration unit

Claims (1)

[Claims] 1. A packet error primary monitoring unit that monitors a missing packet or an abnormal packet by a receiving side protocol, and a packet primary that holds a packet received until the packet is retransmitted after the missing abnormality is detected. A holding unit and a packet order reconstructing unit that reorders all the packets by combining the retransmitted packets and the held packets are arranged. A communication protocol device with a packet retransmission function, comprising: a transmission control unit that temporarily suspends transmission, transmits a packet for which a retransmission request has been received, and then resumes packet transmission from the interrupted location.