JPH0447825A - Packet retransmission processor - Google Patents

Abstract

PURPOSE:To realize efficient packet transmission by retransmitting a registered packet onto a network when acknowledge can not be obtained concerning the packet queue-registered to a retransmission queue even in the case of reaching calculated interval time. CONSTITUTION:Through respective processings such as 'packet transmission processing', 'packet reception processing' and 'packet retransmission processing' to be respectively independently executed through a packet control area 110, among packets to be queue-registered to a retransmission queue 113 with the packet transmission processing, the packet obtaining the acknowledge is successively abandoned. Based on a time stamp set to a time stamp setting area 114, when the packet not obtaining the acknowledge is present thereon even after reaching the interval time stored in a retransmission interval storage part 114, this packet is retransmitted onto a network NW.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a packet retransmission processing device, particularly in a network environment where packet transmission delay changes over time, such as an ink network or a congested local area network. The present invention relates to the implementation of a device capable of optimizing each packet retransmission interval.

[Prior Art] In a network that transmits and receives various types of information as packets, it is common for a packet transmitted from a transmitting station to the network to receive acknowledgment (reception) from the destination to the transmitting station within a predetermined time. (authentication) is not performed, in other words, outgoing packets are lost before reaching their destination, or the amount of traffic on the same network increases and outgoing packets fail to reach their destination. , or if the predetermined time period described above is reached before the acknowledgment from the destination is returned to the transmitting station, the transmitting station retransmits the transmitted packet as a so-called timeout, and the system restarts. I'm trying to recover.

These communication protocols are detailed in, for example, ``Asahi Shimbun Department, ``PC Data Communication Protocol Handbook,'' first edition published March 1, 1985, pp. 178-186,'' but here, as an example, Assuming a network system as shown in the figure, conventional packet transmission and reception processing in such a packet switching system will be described in further detail.

In this FIG. 7, NWl and NW2 are first and second networks that are geographically dispersed, 11
-1n are workstations as transmitting/receiving stations connected to the first network NW1, 21-2m are workstations as transmitting/receiving stations connected to the second network NW2, and 3 is a workstation connected to the above-mentioned geographical location. A router that connects the different distributed networks NWI and NW2 as one Internet and provides a routing information service to each of the workstations connected to these networks, and 100 is installed in each of the workstations, Each of the communication units (actually often configured by software) that executes the transmission and reception of packets described below through the network system is shown. That is, in this network system, in combination with the routing information service provided by the router 3, packets can be exchanged between workstations connected on the same network, such as workstation 11 and workstation 12, as well as between workstations 11 and 12. Packet exchange between workstations connected to different networks, such as the workstations 21 and 22, is also possible through each of the communication units described above. Furthermore, in such systems, the amount of traffic on the network is usually not constant, and the packet transmission delay also changes over time.

FIG. 8 shows an example of a packet exchange sequence based on the above-mentioned communication protocol between a transmitting station (workstation) and its destination, that is, a receiving station (workstation) in such a network system. With reference to FIG. 8, the manner in which packets are exchanged on the network will be described. In FIG. 8, rs eqJ is a number indicating the order of packets, and "a" is a number that indicates the number of the received packet (rseq+lJ).
"ack" is the "seq+IJ number" of the packet received at the receiving station, which is notified from the receiving station in response to this request. Based on this, it is determined that the transmitting packet has been acknowledged at the receiving station.

Now, in this Fig. 8, when viewed from the transmitting station side, (1) First, rs e q-IJ ~ rs e q-3J
three packets are sent to a specific receiving station (destination) (the number of packets that can be sent at one time is determined by the receiving window size at the receiving station). Then, the above notification request rarJ is added to the last packet [5eq-3J.

(2) Wait for the response rack-4J from the receiving station.

(3) If there is a response of ``ack-4J,'' it is assumed that the transmitted packets rseq-IJ to rseq-3J have been acknowledged, and then the packets rseq4 to rseq are sent.
Three packets of 6J are sent to the same receiving station. Here again, the above notification request rarJ is added to the last packet "5eq-6J."

(4) Wait for an ack-7J response from the receiving station.

(5) If there is a response of rack-7J, it is assumed that the transmitted packets rseq=4J to "seq-6J" have also been acknowledged, and the communication related to the packet transmission ends.

The exchange of packets between these transmitting and receiving stations is shown assuming that such processing will be realized.
As shown in FIGS. 8(a), 8(b), and 8(c), in reality, the processing content changes slightly depending on the amount of traffic on the network.

That is, in the case of FIG. 8(a), rseq-1''~
``Although up to 5 packets of 5eq = 5J were sent normally, ``the packet of 5eq = 6J was lost and its acknowledgment was not obtained, so after the retransmission interval time, that is, the predetermined time, the corresponding “5eq-
In the case of FIG. 8(b), basically the same processing as that shown in FIG. 8(a) is executed; Compared to case a), the amount of network traffic is smaller, that is, the propagation delay is smaller (the angle of the arrow is smaller), so there is ample time in the retransmission interval when retransmitting the packet. , Conversely, in the case of FIG. 8(c), the amount of network traffic is large, that is, the propagation delay is large (the angle of the arrow is large), so it takes time to transmit the packet and receive the response.
In the end, after transmitting the packet 5eq=3j, the retransmission interval time elapsed before the response ack-4J was obtained from the receiving station, and the packet 5eq-3J and the notification request ra rJ were unnecessary. has been resent.

[Problems to be Solved by the Invention] As described above, according to the above communication protocol, during packet transmission, the transmitted packet may be lost on the network, and acknowledgment for the transmitted packet cannot be obtained. Even in such a case, since the packet is retransmitted after the retransmission interval time has elapsed, the network system itself will be able to recover smoothly without becoming unable to communicate. ,
These retransmissions of packets are performed based on a fixed interval time determined by the network system, so if the amount of traffic changes on the network, the exchange of packets between the sending and receiving stations will be delayed. Efficiency would be significantly reduced.

In other words, when the amount of traffic decreases (see Figure 8(b)), this retransmission interval time becomes relatively long, resulting in unnecessary waiting time, and conversely, the amount of traffic decreases. When the amount of packets increases (see FIG. 8C), the retransmission interval time becomes relatively short, resulting in unnecessary retransmission of packets.

The present invention has been made in view of these circumstances, and provides a packet retransmission processing device that successively optimizes the retransmission interval and, in turn, realizes always efficient packet transmission according to the traffic situation on the network each time. The purpose is to

[Means for Solving the Problems] In the present invention, (a) a retransmission queue in which packets to be retransmitted are registered in a queue; (b) the traffic status of the network each time is recorded based on the acknowledgment history from the destination. Recording means.

(e) Interval calculation means for calculating a retransmission interval when retransmitting a packet according to the traffic situation each time the packet is recorded.

(d) A control means for retransmitting the registered packet onto the network when an acknowledgment for the packet registered in the retransmission queue is not obtained even after the calculated interval time has been reached.

The packet retransmission processing device is configured with the following.

This packet retransmission processing device is provided in the communication section of each transmitting/receiving station.

[Operation] The traffic status recorded in the recording means is the acknowledgment history, that is, the history of each packet sent in the previous (for example, the previous) packet transmission cycle until the actor/soj is obtained from the destination. Since the information is based on progress (e.g. average elapsed time, etc.),
This information 1 will naturally be reflected in the amount of traffic on the network up to that point (or just before that).

Also, the interval calculation means sets the retransmission interval based on the recorded information (traffic status), for example: ◆Ct is shorter when the traffic volume tends to be low, ◆Ct is shorter when the traffic volume tends to be high. Sometimes for a long time, each time I try to send a packet,
In the end, this newly calculated retransmission interval will be a time optimized according to the traffic situation on the network at that time.

Therefore, if the above-mentioned control means executes the retransmission control based on this optimized interval time, the above-mentioned wasteful waiting time may occur, or the retransmission of the retransmission may occur unnecessarily. Efficient communication and soto transmission will be realized without the need for any confusion.

[Embodiment] FIG. 1 shows an embodiment of a transmitting/receiving station communication section to which a packet retransmission processing device according to the present invention is applied.

The communication unit 100 shown in FIG. 1 also includes each transmitting/receiving station (
(workstation in the example in Figure 7), basically sends and receives the packets mentioned above, and if an acknowledgment is not obtained within the retransmission interval for a packet sent on the network. , resend the relevant transmission to recover the system;
(1 operation is executed. However, in this embodiment, the retransmission interval is actively increased or decreased according to the traffic situation on the network at each time, thereby improving the packet transmission efficiency. .

Incidentally, in this embodiment, the retransmission interval is determined each time based on the following equation.

RI n+1 − (RIn xa+APAxb)/(a+b) where, PA a, b: Retransmission interval: Any natural number (0, 1° 2.8.,,, ): For each packet transmitted in the previous packet transmission cycle The average elapsed time until an acknowledgment is obtained from the destination is a constant, i.e., the retransmission interval rRInil to be determined.
J is based on the previous retransmission interval "RInJ" and the average elapsed time rAPAJ until an acknowledgment is obtained from the destination for each packet transmitted in the immediately preceding packet transmission cycle, and weighting is, for example, based on the constants a and b. are equal, these “RIn J and rAPA
Calculated as the average time of J. In particular, this rAPAJ has a tendency to change depending on the traffic situation on the network, the longer the traffic volume is, or the shorter the traffic volume is lower.
Through this equation (1), the retransmission interval rRIn
By determining +IJ, efficient packet transmission with less waste can be realized.

The details of this embodiment of the apparatus that enables such highly efficient packet transmission will be sequentially explained below.

First, with reference to FIG. 1, the configuration and functions of each part of the apparatus of this embodiment will be explained.

In the communication unit 100 shown in FIG. 1, 110 is a packet control area (work area) as the communication unit 100, and this control area 110 includes
A transmission queue 111 in which packets transmitted to NW are queued; a reception queue 112 in which packets received from the same network NW are queued; a retransmission queue 113 in which packets to be retransmitted are queued; A time stamp setting area 114 in which the transmission time is set and registered is provided.

In the communication unit 100, direct packet transmission/reception operations with the network NW, including packet retransmission, are as follows:
This will be done through this packet control area 110.

Further, in the communication unit 100, the transmission processing unit 121 constructs a packet based on the transmission information for which a transmission request has been made from the station (the workstation), and sends it to the transmission queue 111 of the packet control area 110, etc. The reception processing unit 122 is a part that mainly executes various processes required when transmitting a packet. Based on the decoded content, this is transferred as received information to the information processing unit in the station (the workstation) shown in Figure 7, or if the extracted packet is determined to be an acknowledgment from the destination. The retransmission processing unit 123 is a part that executes various processes mainly required when receiving a packet, such as further capturing the elapsed time until the transmission packet is acknowledged. For packets registered in the retransmission queue 113 of This is the part that executes various types of processing. The packet control area 100 includes these transmission processing section 121, reception processing section 122, and retransmission processing section 123.
are each used as a work area when performing required packet processing.

The communication control unit 130 includes a clock 141, a retransmission interval calculation unit 142, a calculation interval storage unit 143,
Retransmission interval storage section 144, acknowledgment progress recording section 145, and acknowledgment packet number counter 146
Based on the information obtained from each of these sections, it assists the various processes executed by the transmission processing section 121, reception processing section 122, and retransmission processing section 123, and centrally controls their operations. This is the part where you do things.

Various functions required as the communication section 100 are also included in the transmission processing section 121, reception processing section 122, and retransmission processing section 1.
This is realized through the overall control of the communication control section 130 over the communication control section 23.

Note that the clock 141 that is comprehensively managed by this communication control unit 130 is a clock 141 that measures the retransmission interval calculated above, the interval for recalculating the retransmission interval (calculation interval), and the time when the transmitted packet is acknowledged at the destination. This is the part that performs timekeeping and time-limiting operations related to the elapsed time until the retransmission interval calculation part 14.
2 is a part that calculates the interval time for packet retransmission according to the traffic situation on the network NW each time using the above formula (1), and the calculation interval storage unit 143 is a part that calculates the interval time for retransmission of packets according to the traffic situation on the network NW at each time.
The retransmission interval storage unit 144 stores the time interval at which the calculation by 42 is executed, and the retransmission interval storage unit 144 stores the time calculated by the retransmission interval calculation unit 142 and updates it each time. The acknowledgment progress recording section 145 is a section in which "the elapsed time until the transmitted packet is acknowledged" that is taken in through the reception processing section 122 is recorded, and the acknowledge packet number counter 146
is a part that counts the number of transmitted packets that have actually been acknowledged based on the acknowledgment reception judgment made by the reception processing analyzer 122.

2 to 5 illustrate specific processing procedures of the transmission processing section 121, -reception processing section 122, and retransmission processing section 123, which are executed mainly by the communication control section 130. , Next, with reference to FIGS. 2 to 5, "packet transmission processing", "packet reception processing", and "packet retransmission processing" of the apparatus of this embodiment will be explained.
Each operation will be explained in turn.

First, referring to FIG. 2, the operation related to "packet transmission processing" will be explained.

Now, suppose that transmission information that is desired to be transmitted from the own station (own workstation) to another station is added to the transmission processing section 121. In the communication control section 130', this transmission processing section 12
1, the transmission processing section 121 starts transmitting processing in the manner described below.

(1) Construct a packet based on the above transmission information, and send the constructed packet to the packet control area 100.
(Step 5 in Figure 2)
12).

(2) Next, set the time at which this construction packet was queued in the timestamp setting area 114 in the packet control area 110. That is, a time stamp is set (step 813 in FIG. 2).

This time stamp is set based on timekeeping information output from the clock 141.

(3) Then, the packet queued in the transmission queue 111 is sent to the network NW. Step 5 in FIG.
14), and in preparation for unexpected packet retransmission, the same transmission packet is also stored (queued) in the retransmission queue 113 (step 515 in FIG. 2).

The above processing is executed every time transmission information is added to the transmission processing section 121.

Next, with reference to FIGS. 3 and 4, operations related to "packet reception processing" will be described. However, for convenience, "reception processing" as a packet transmitting station will be explained here.

“Packet reception processing” is performed each time the station (workstation) is started up by turning on the power, etc. (A) Retransmission interval time information stored in the retransmission interval storage unit 144.

(B) Calculation interval time information of the retransmission interval stored in the calculation interval storage unit 143.

(C) Elapsed time information recorded in the acknowledgment progress recording section 145.

(D) Information on the number of acknowledged transmitted packets counted by the acknowledged packet number counter 146.

It is activated after the initialization process (step 520 in FIG. 3) is completed (step 530 in FIG. 3).

After being activated, the communication control unit 130 executes the processes listed below through the reception processing unit 122.

(1) While monitoring the reception queue 112 in the packet control area 110, wait for a packet to be received into the reception queue 112 (step 531 in FIG. 4).

(2) When a packet is received, it is necessary to judge whether or not this indicates an acknowledgment update, that is, whether or not a new acknowledgment has been obtained for the packet transmitted by the own station.Steps in Figure 4 532), if it is determined no, it waits again for new reception of the packet.

(3) If it is determined that this is an acknowledgment update, the acknowledged transmission packet is deleted (discarded) from the retransmission queue 113 (step 833 in FIG. 4) and stored in the same packet control area 110. Based on the time stamp set in the time stamp setting area 114, the elapsed time until the transmission packet is acknowledged is recorded in the acknowledgment progress recording section 145 (step 534 in FIG. 4). In addition to this,
The count value of the acknowledge packet number counter 146 is also incremented by one.

(4) While the packet received in the reception queue 112 indicates an acknowledgment update, the process in (3) above is repeated, and when the packet indicating the acknowledgment update no longer exists in the reception queue 112, the process is repeated again. Waits for new packet reception (step 535 in FIG. 4).

The above processing is performed from the network NW to the reception queue 112.
Executed every time a packet is received.

Finally, the operation related to "packet retransmission processing" will be explained with reference to FIGS. 3 and 5.

This "packet retransmission process" also includes the above-mentioned initialization process (step 520 in FIG.
) is started (step 540 in FIG. 3).

After being activated, the communication control unit 130 controls the clock 14.
Every time the time limit as a retransmission processing cycle preset to 1 is reached (step 541 in FIG. 5), the following processes are executed through the retransmission processing unit 123.

(1) The retransmission queue 1 in the packet control area 110
The packets registered in queue No. 13 are taken out (step 542 in FIG. 5). Here, it is assumed that there is already a packet registered in the retransmission queue 113 as a result of the previous "packet transmission process".

(2) When it is determined that the packet exists in the retransmission queue 113 (step 843 in FIG. 5), the time stamp set in the time stamp setting area 114 in the packet control area 110 is then set. ,
Based on the retransmission interval time stored at that point in the retransmission interval storage unit 144 (the initial value is set as appropriate due to the above initialization) and the time measurement information by the clock 141, the packet is It is determined whether the retransmission interval time has been reached (step 544 in FIG. 5).

(8) When it is determined that the retransmission interval time has been reached, the packet is registered in the transmission queue 111 again, and then (2) and (
3) (see steps S13 to S15 in FIG. 2), the same packet is transmitted (retransmitted) from the transmission queue 111 onto the network NW (step 54 in FIG. 5).
5), the same transmitted packet is re-stored (re-queued) in the re-transmission queue 113 in preparation for re-transmission of the packet (fifth
Figure step 546).

Processes such as this are performed.

(4) After that, the interval time for retransmission interval calculation stored at that point in the calculation interval storage unit 143 (the initial value is set as appropriate due to the above initialization) and the clock 141, it is determined whether the calculation interval time has been reached (step 547 in FIG. 5).

(5) If it is determined that this calculation interval time has been reached, through the retransmission interval calculation unit 142,
Retransmission interval rRIn+IJ based on formula (1) above
(step 548 in FIG. 5). For example, if the time information stored in the retransmission interval storage unit 144 at that time is set as the retransmission interval rRInJ,
Also, among the elapsed time information recorded at that point in the acknowledgment progress recording section 145, the average elapsed time rAP is the average time of the information collected during the previous calculation interval.
As AJ, these are respectively sent to the retransmission ink-pulse calculation unit 142, and the weightings set in advance in the retransmission interval calculation unit 142 are constants ra(=3)j and rb.
(-1) In conjunction with J, the same retransmission interval calculation unit 14
2 to execute the above equation (1). Then, the value of retransmission interval rRIn+IJ obtained as a result of this calculation is stored in retransmission interval storage section 144 as a new retransmission interval time to be adopted next time. That is, the information stored in the retransmission interval storage section 144 is updated each time the retransmission interval is recalculated. Furthermore, depending on the value of the calculated retransmission interval rRIn+LJ and the value of the above-mentioned average elapsed time rAPA, that is, depending on the traffic situation on the network NW, the optimal calculation interval each time changes slightly. The control unit 130 also updates the value of the calculation interval according to these values (the optimum value of the calculation interval is automatically determined according to the value of the retransmission interval rRIn+IJ and the value of the average elapsed time rAPAJ), and the updated calculation The interval time is also stored in the calculation interval storage unit 143 as a new calculation interval to be adopted next time.
shall be memorized.

The above processing is executed every time the retransmission processing cycle, which is preset in the clock 141, is reached.

In addition, in the process (2) above, if it is determined that no packet exists in the retransmission queue 113 (step 543 in FIG. If it is determined that the calculation interval time has not been reached (step 544 in FIG. 5), the process directly proceeds to the process (4) for determining whether or not the calculation interval time has been reached (step 547 in FIG. 5).

In addition, in the process (4), if it is determined that the calculation interval has not been reached, the state waits for timeout for the above processing cycle (step 541 in FIG. 5).
becomes.

Incidentally, in this embodiment, the temporal relationship between the processing cycle, retransmission interval, and calculation interval in this "packet retransmission processing" is as follows. .

As described above, according to the embodiment device, through the processes of "packet transmission processing", "packet reception processing", and "packet retransmission processing" which are each independently executed via the packet control area 110, ◆ Among the packets registered in the retransmission queue 113 as a result of the packet transmission process, packets for which an acknowledgment has been obtained are sequentially discarded.

◆Based on the time stamp set in the time stamp setting area 114, if there is a packet for which an acknowledgment has not been obtained even after the interval time stored in the retransmission interval storage unit 144 is reached, this packet is sent to the network NW.
Resend above.

These basic functions are well satisfied. In particular, in the device of the embodiment, based on equation (1) above, ◆ Shorter time when the amount of traffic on the network NW tends to be small, ◆ Longer time when the amount of traffic on the network NW tends to be large. In this aspect, the retransmission interval that is the optimal time is calculated each time according to the traffic situation on the network NW, and the retransmission timing for retransmitting the packet is determined based on the calculated retransmission interval. The occurrence of wasteful waiting time and unnecessary retransmission of packets can also be effectively suppressed.

FIG. 6 shows an example of the manner in which packets are exchanged by the device of the above embodiment. In the device, as shown in FIG. The retransmission interval "RInJ" and the average elapsed time (average elapsed time until the transmitted packet is acknowledged) rAPA determined in the immediately preceding calculation interval (packet transmission cycle)
Since the determined retransmission interval rRIn+LJ is determined as described above based on After a short period of time,
The wasteful waiting time that existed in the past is now suppressed,
In addition, as illustrated in FIG. 8(c), the network N
When the amount of traffic on W is large, the determined retransmission interval rRIn+Ij becomes relatively long, and unnecessary retransmission of packets as in the past is suppressed. Even if there is such a problem, efficient packet transmission can be realized in accordance with the traffic situation each time.

In the above embodiment, the retransmission interval l"RIn+lJ to be adopted next time is determined based on the above equation (1), but in addition, for example, RIn+1 "" (RInXa+APAXc
Xb)/(a+b) , (2) However, C: A margin rc (for example, c-1, 5) J, which is a margin for the average elapsed time APA, may be further taken into account. As a result, the calculated retransmission interval rR
The value of In+lJ also has a margin, and the retransmission interval is not set extremely short. In other words, unnecessary packet retransmission can be suppressed more effectively.

In the same embodiment, the value of the above-mentioned average elapsed time rAPA is the average elapsed time information collected during the immediately preceding calculation interval among the elapsed time information currently recorded in the acknowledgment progress recording section 145. The above retransmission interval rRIn+IJ is adopted, thereby responding more sensitively to the traffic situation on the network NW.
is calculated, but this selection is not particularly limited. That is, the acknowledgment progress recording section 14
The elapsed time information recorded in 5 is information that corresponds to the traffic situation on the network NW, so if a sensitive response is not necessarily desired, it may be collected before the previous calculation interval. Of course, the average time including the elapsed time information obtained may be used as the value of "AP AJ".

Furthermore, in the above embodiment, the calculation interval is also calculated as follows:
Although the calculation interval is updated according to the value of the calculation interval and the average elapsed time rAPAJ, it is not necessarily necessary to make the calculation interval variable. That is, like the processing cycle for the retransmission process, it is also possible to fix this in advance depending on the characteristics of the network system to be adopted.

By the way, in the above-mentioned "packet reception processing", four things always happen:
The destination of the received packet is also checked based on the address information included in the packet, but for the sake of convenience, a detailed description of the protocol related to these processes is omitted here.

Further, although the apparatuses shown in the above embodiments are usually configured by software, it is of course possible to configure them by hardware. The packet retransmission processing device according to the present invention is not limited to these techniques.

[Effects of the Invention] As explained above, according to the present invention, the retransmission interval that is the optimal time is calculated each time according to the network traffic situation, and the retransmission interval when retransmitting a packet is calculated based on the calculated retransmission interval. Since the retransmission timing is determined, efficient packet transmission is achieved by suppressing wasteful waiting time and unnecessary retransmission of packets, which in turn prevents extreme increases and decreases in traffic volume for the network system as a whole. This will lead to smoother system operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of a packet retransmission processing device according to the present invention. FIG. 2 is a flowchart illustrating an example of a procedure for packet transmission processing by the apparatus of this embodiment. FIG. 3 is a flowchart mainly showing the procedure for initialization processing of the apparatus of the embodiment. FIG. 4 is a flowchart illustrating an example of a procedure for packet reception processing of the apparatus of the embodiment. FIG. 5 is a flowchart illustrating an example of a procedure for packet retransmission processing in the apparatus of the embodiment. FIG. 6 is a sequence diagram schematically illustrating a method for determining a retransmission interval by the apparatus of the embodiment. FIG. 7 is a block diagram showing an example of a network system to which the packet retransmission processing device according to the present invention is applied. FIG. 8 is a sequence diagram illustrating a conventional manner of transmitting and receiving packets in the network system. 100, Communication Department, 110. ,,Packet control area 111 ,,Transmission queue 112. ,,Receive queue 113. ,,Retransmission queue 114. , , Time stamp setting area 121 , , Transmission processing unit 122
, Reception processing section 123 , Retransmission processing section 130
, , Communication control unit, 141 , , Clock, 142 . . Retransmission interval calculation unit, 143, Calculation interval storage unit, 144, Retransmission interval storage unit,
145 , , Acknowledgment progress recorder, 1468 . ,
Acknowledge packet number counter. Figure 2 Figure 3 Figure 4 Figure 4

Claims (1)

[Scope of Claims] In a packet retransmission processing device that retransmits a transmitted packet onto the network when an acknowledgment is not obtained from the destination of the packet transmitted on the network, the retransmitted packet is registered in a queue. a retransmission queue for recording, a recording means for recording the traffic situation of the network each time based on the acknowledgment history, and a retransmission interval for retransmitting the packet according to the recorded traffic situation each time. and a control means for retransmitting the registered packet onto the network when an acknowledgment for the packet registered in the retransmission queue is not obtained even after the calculated interval time is reached; A packet retransmission processing device comprising: