JP2005277704A - Data distribution management device and data distribution management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify buffer operation in the flow control of a TCP in a data distribution management device. <P>SOLUTION: The data distribution management device is provided with a packet transfer part for transferring a received data packet to a destination, a storage which stores a segment of the data packet transferred by the packet transfer in a buffer and makes the storage area of the segment in the buffer available corresponding to the reception of a delivery acknowledgement packet from the destination, and a reply part which obtains a reception window size on the basis of the available capacity of the buffer and a segment size and replies the reception window size to a transmission origin of the data packet received by the packet transfer part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data distribution management apparatus that performs data transfer by, for example, TCP (Transmission Control Protocol).

In TCP flow control known as a so-called reception window, the reception terminal device notifies the transmission terminal device of the reception window size, which is the maximum amount of information that can be received without a delivery confirmation response, and the transmission terminal device is notified. By transmitting data having an amount of information that does not exceed the window size, the receiving terminal device can receive all transmitted data without overflowing.
For example, in the conventional data distribution management apparatus disclosed in Patent Document 1, in order to efficiently perform such data transfer by TCP when a communication line having a large transmission delay such as a satellite line is used, Based on the original throughput information, the buffer size of the buffer for storing the received data segment is variably set.

JP 2003-124984 A

  The conventional data distribution management device disclosed in Patent Document 1 has a problem that complicated control of variably setting the buffer size is necessary.

  The present invention has been made to solve the above-described problems, and aims to simplify buffer operations in, for example, TCP flow control in a data distribution management apparatus.

  A data distribution management device according to the present invention stores a packet transfer unit that transfers a received data packet to a destination, a segment of the data packet transferred by the packet transfer unit in a buffer, and a delivery confirmation response packet from the destination Corresponding to the reception of the segment, the storage unit that makes the storage area of the segment empty in the buffer, the reception window size is obtained based on the empty space of the buffer and a predetermined segment size, and the reception window size is determined as the packet transfer And a return unit that returns the data packet received by the unit to the transmission source.

  According to the present invention, in the data distribution management device, the buffer operation in, for example, TCP flow control can be simplified by obtaining the reception window size based on the buffer free space and a predetermined segment size.

Embodiment 1 FIG.
The data distribution management device according to Embodiment 1 of the present invention obtains a reception window size as a product of the number of segments that can be stored in a buffer free space and a predetermined maximum segment size, thereby reducing a transmission delay such as a satellite line. Even when a large communication line is used, the buffer operation in the TCP flow control can be simplified.

FIG. 1 is a block diagram showing a data distribution management apparatus according to Embodiment 1 of the present invention.
In FIG. 1, TCP data transfer is performed from the first terminal device 1 to the second terminal device 2, and the data distribution management device 3 is arranged therebetween. The first terminal device 1 and the data distribution management device 3 are connected by a high-speed communication line using a LAN, and the data distribution management device 3 and the second terminal device 2 are connected by, for example, a satellite line. They are connected by a communication line with a large transmission delay. In addition, by arranging the data distribution management device 3, all of the signals transmitted from the first terminal device 1 are transmitted in the second terminal device 2 even when a communication line having a large transmission delay such as a satellite line is used. The data can be received without overflowing.

Further, the data distribution management device 3 receives a TCP data packet transmitted from the first terminal device 1 and transfers it to the second terminal device 2, and a delivery confirmation TCP for the received TCP data packet. A return unit 32 that generates an ACK (Acknowledgement) packet and returns it to the first terminal device 1, a buffer 34 that stores a segment of the TCP data packet to be transferred, and the transferred TCP data packet to the second terminal device 2 Is received from the second terminal device 2, and the received delivery confirmation TCP-ACK packet is terminated, and the holding unit 33 that controls the buffer 34 to hold the segment of the corresponding TCP data packet until then. From the information management unit 35 that holds information such as the maximum segment size of the connection It is made.
Note that the buffer 34 and the holding unit 33 constitute a storage unit.

  In the first embodiment, the data transfer in one TCP connection between the first terminal device 1 and the second terminal device 2 will be described. However, by dividing the buffer unit 34 for each connection, a plurality of data can be transferred. Can be supported. In addition to the first terminal device 1 and the second terminal device 2, there may be a terminal device.

Next, the operation will be described.
In FIG. 2, at the time of transmitting a packet AKo1 that is a notification of the reception window size from the data distribution management device 3 to the first terminal device 1 in this example, five data are stored in the data holding buffer 34 of the connection. Assume that the packet buffers Buff1 to Buff5 are free. Note that the packet AKo1 is returned in response to the reception of the TCP data packet from the first terminal device 1, but FIG.

The maximum segment size set between the first terminal device 1 and the second terminal device 2 when the connection is established is recorded in the information management unit 35, and here it is 1460 bytes. Accordingly, since five packet buffers are free, the reception window size notified by AKo1 is given by the following equation.
Reception window size = 1460 bytes × 5 = 7300 bytes (Formula 1)

  Thereafter, when a large amount of data distribution occurs from the first terminal device 1 to the second terminal device 2 at a certain point in time, the first terminal device 1 waits for a delivery confirmation TCP-ACK packet from the data distribution management device 3. Instead, 7300 bytes of data is divided into packets DTr1 to DTr5 as data segments (hereinafter abbreviated as segments) and sequentially transmitted.

  In the data distribution management device 3, the transfer unit 31 receives the TCP data packets DTr1 to DTr5 transmitted by the first terminal device 1 and stores them in the packet buffers Buff1 to Buff5 of the buffer 34. Packets DTs1 to DTs5 in which the same data as the packets DTr1 to DTr5 are stored are transmitted to the terminal device 2. The return unit 32 returns delivery confirmation TCP-ACK packets AKs 1 to AKs 5 to the first terminal device 1. Further, packet buffers Buff1 to Buff5 in which segments of the packets DTr1 to DTr5 are stored are held by the control of the holding unit 33.

When the data distribution management device 3 receives the packet DTr1, there are four free packet buffers. Therefore, the reception window size notified by the returned delivery confirmation TCP-ACK packet AKs1 is expressed by the following equation.
Receive window size = 1460 bytes × 4 = 5840 bytes (Formula 2)
Similarly, the reception window size notified by the packet AKs5 is as follows.
Receive window size = 1460 bytes x 0 = 0 bytes (Formula 3)

  At this time, since the data distribution management device 3 cannot receive any more data, the first terminal device 1 suspends the next data transmission until the reception window is restored.

  When the second terminal device 2 sequentially receives the TCP data packets DTs1 to DTs5 transferred by the data distribution management device 3, the second terminal device 2 sequentially returns the delivery confirmation TCP-ACK packets AKr1 to AKr5. The holding unit 33 of the data distribution management device 3 terminates this and releases the packet buffers Buff1 to Buff5 in which the segments of the corresponding TCP data packets are stored so that they can be reused (that is, empty). It should be noted that emptying can mean that the packet buffer can be overwritten at this point, or the packet buffer can be erased.

In this example, the window probe packet AKo2 from the first terminal apparatus 1 is received when the packet AKr3 is terminated and the packet buffer Buff3 in which the segment of the corresponding TCP data packet is stored is released. The data distribution management device 3 returns a packet AKo3 as a response to the window probe packet AKo2. The reception window size notified by the packet AKo3 is given by the following equation because three packet buffers are empty at that time.
Reception window size = 1460 bytes × 3 = 4380 bytes (Formula 4)

  The first terminal device 1 knows the recovery of the reception window of the data distribution management device 3 by receiving the packet AKo3, and resumes transmission of 4380 bytes of the subsequent data. The data is divided into TCP data packets DTr6 to DTr8 and transmitted to the data distribution management device 3 in order.

In the data distribution management device 3, when the packet DTr6 is received, the packet buffer is further released, and the reception terminal size of the following expression is notified to the first terminal device 1 by the packet AKs6.
Receive window size = 1460 bytes × 4 = 5840 bytes (Formula 5)

In the first terminal device 1, the value shown in Expression 6 is expected as the reception window size of the delivery confirmation TCP-ACK packet DTr 6. The device 3 determines that it can be received, and transmits a packet DTr9 for storing the last data.
Reception window size = 1460 bytes × 2 = 2920 bytes (Formula 6)

  As described above, in the data distribution management device according to Embodiment 1 of the present invention, among the data holding buffers, the number of free packet buffers (that is, the number of segments that can be stored in the buffer space) and the maximum segment size are set. By notifying the reception window size obtained by multiplication, the buffer operation in TCP flow control can be simplified even through a communication line having a large transmission delay such as a satellite line.

Embodiment 2. FIG.
In the first embodiment, the reception window size notified to the first terminal device 1 is the maximum number of segments in the number of empty packet buffers in the data holding buffer 34 of the connection (that is, the number of segments that can be stored in the buffer empty space). Although a value obtained by multiplying the size is used, in the second embodiment, this value is further multiplied by a predetermined coefficient.

  FIG. 3 is a block diagram showing a data distribution management apparatus according to Embodiment 2 of the present invention. In FIG. 3, the data distribution management apparatus 3 further includes a setting management unit 36 that holds the coefficient.

Next, the operation will be described. Here, the coefficient is set to 0.7.
In FIG. 4, as in the first embodiment, the data distribution management device 3 notifies the first terminal device 1 of the following reception window size by the packet AKo1.
Reception window size = 1460 bytes × 5 × 0.7 = 5110 bytes (Formula 7)

  Thereafter, when a large amount of data distribution occurs from the first terminal device 1 to the second terminal device 2 at a certain point in time, the first terminal device 1 waits for a delivery confirmation TCP-ACK packet from the data distribution management device 3. Instead, 5110 bytes of data are divided into packets DTr1 to DTr4 and transmitted sequentially. The segment stored in each TCP data packet is not necessarily the maximum segment size, but in this example, it is 1460 bytes for packet DTr1, 1200 bytes for packet DTr2, 1250 bytes for packet DTr3, and 1200 bytes for packet DTr4. There are a total of 5110 bytes.

  In the data distribution management device 3, the TCP data packets DTr1 to DTr4 transmitted by the first terminal device 1 are received by the transfer unit 31, stored in the packet buffers Buff1 to Buff4 of the buffer 34, and the transfer unit 31 stores the second data Packets DTs1 to DTs4 in which the same data as the packets DTr1 to DTr4 are stored are transmitted to the terminal device 2. In addition, the return unit 32 returns delivery confirmation TCP-ACK packets AKs 1 to AKs 4 to the first terminal device 1. Further, the packet buffers Buff 1 to Buff 4 of the buffer 34 in which the segments of the TCP data packets DTr 1 to DTr 4 are stored are held under the control of the holding unit 33.

When the data distribution management device 3 receives the packet DTr1, there are four free packet buffers. Therefore, the reception window size notified by the returned delivery confirmation TCP-ACK packet AKs1 is expressed by the following equation.
Reception window size = 1460 bytes × 4 × 0.7 = 4088 bytes (Formula 8)
Similarly, the reception window size notified by the packet AKs4 is as follows.
Receive window size = 1460 bytes × 1 × 0.7 = 1022 bytes (Formula 9)

Since the first terminal device 1 knows that the data distribution management device 3 can receive the next data, the first terminal device 1 further transmits a packet DTr5. Since the empty packet buffer is depleted when receiving the packet DTr5, the data distribution management device 3 notifies the value of the following expression as the window size value of the delivery confirmation TCP-ACK packet.
Receive window size = 1460 bytes × 0 × 0.7 = 0 bytes (Formula 10)
Since the data distribution management device 3 cannot receive any more data, the first terminal device 1 waits for subsequent data transmission until the reception window is restored.

  When the second terminal device 2 sequentially receives the packets DTs1 to DTs5 transferred by the data distribution management device 3, the second terminal device 2 sequentially returns the delivery confirmation TCP-ACK packets AKr1 to AKr5. The holding unit 33 of the data distribution management device 3 terminates this, and releases (that is, vacates) the packet buffer in which the segment of the corresponding data packet is stored so that it can be reused.

In this example, when the packet AKr4 is received and the packet buffer Buff4 in which the segment of the corresponding TCP data packet is stored is released, the window probe packet AKo2 from the first terminal device 1 is received. The data distribution management device 3 returns a packet AKo3 as a response to the window probe AKo2. The reception window size notified by the packet AKo3 is expressed by the following equation because four packet buffers are empty at that time.
Reception window size = 1460 bytes × 4 × 0.7 = 4088 bytes (Formula 11)

  The first terminal device 1 knows that the reception window of the data distribution management device 3 has been recovered by receiving the packet AKo3, and resumes transmission of 4088 bytes of the subsequent data. The data is divided into TCP data packets DTr6 to DTr8 and transmitted to the data distribution management device 3 in order.

In the data distribution management device 3, when the packet DTr6 is received, the packet buffer is further released, and the first terminal device 1 is notified of the window size of the following expression by a delivery confirmation TCP-ACK packet for the packet DTr8. .
Reception window size = 1460 bytes × 2 pieces × 0.7 = 2044 bytes (Formula 12)
Since the first terminal device 1 knows that the data distribution management device 3 can further receive the next data, the first terminal device 1 transmits a packet DTr9 for storing the last data.

  As described above, in the data distribution management device according to the second embodiment of the present invention, among the data holding buffers, the number of free packet buffers (that is, the number of segments that can be stored in the buffer free space) and the maximum segment size By notifying the reception window size obtained by multiplying by a predetermined coefficient, it is possible to simplify the buffer operation in the TCP flow control even when data packets less than the maximum segment size coexist.

Embodiment 3 FIG.
In the first embodiment, as the reception window size notified to the first terminal device 1, the maximum number of segments is equal to the number of empty packet buffers (that is, the number of segments that can be stored in the buffer free space) of the data holding buffer 34 of the connection. Although a value obtained by multiplying the size is used, in Embodiment 3, the average segment size is used instead of the maximum segment size.

  FIG. 5 is a block diagram showing a data distribution management apparatus according to Embodiment 3 of the present invention. In FIG. 5, the average length calculation unit 37 holds the segment sizes of a plurality of latest data packets and calculates the average segment size.

Next, the operation will be described.
The basic operation is the same as that of the first embodiment, but when receiving a TCP data packet from the first terminal device 1, the segment size is set to the number of the packet buffer used for receiving the packet. The data is stored in the segment size storage position of the corresponding average length calculation unit 37. For example, when a segment is received by the packet buffer Buff3, the segment size is stored in the segment size storage position Buff3size of the average calculation unit 37.

  When notifying the first terminal apparatus 1 of the reception window size as a delivery confirmation TCP-ACK packet, the respective segment sizes held in the average length calculation unit are added together, and the value divided by the holding number is used as the average segment size. .

  As described above, in the data distribution management device according to the third embodiment of the present invention, the number of free packet buffers (that is, the number of segments that can be stored in the buffer space) and the average segment size among the data holding buffers are calculated. By notifying the reception window size obtained by multiplication, even if the actual segment size of the TCP data packet is smaller than the maximum segment size set at the time of connection establishment, the TCP does not overflow the received data. The buffer operation in the flow control can be simplified.

Embodiment 4 FIG.
In the third embodiment, the reception window size notified to the first terminal apparatus 1 is a value obtained by multiplying the number of empty packet buffers in the data holding buffer 34 of the connection by the average segment size. In the fourth embodiment, a predetermined coefficient is further multiplied and used.

  FIG. 6 is a block diagram showing a data distribution management device according to Embodiment 4 of the present invention. In FIG. 6, the data distribution management device 3 includes a setting management unit 36 in order to hold the coefficient.

Next, the operation will be described.
In FIG. 6, the basic operation is the same as the operation of the third embodiment, but when the reception terminal size is notified to the first terminal apparatus 1 as a delivery confirmation TCP-ACK packet, the average segment is added to the number of free packet buffers. The value multiplied by the size is further multiplied by a coefficient held in the setting management unit 37 and used.

  As described above, in the data distribution management device according to the fourth embodiment of the present invention, among the data holding buffers, the number of free packet buffers (that is, the number of segments that can be stored in the buffer space) and the average segment size By notifying the reception window size obtained by multiplying a predetermined coefficient, the segment size of the TCP data packet is relatively small compared to the maximum segment size negotiated at the time of establishing the connection, and the segment size varies from packet to packet. Even when there are many, it is possible to realize simplification of buffer operation in TCP flow control without overflowing received data.

Embodiment 5 FIG.
In the first embodiment, when a plurality of connections are supported, a packet buffer that stores a data packet transmitted by the first terminal apparatus 1 is allocated in advance for each connection. Provide a packet buffer shared by the connection.

FIG. 7 is a block diagram showing a data distribution management apparatus according to Embodiment 5 of the present invention. In FIG. 7, in the buffer 34, 341, 342, and 343 are a pool 1, a pool 2, a pool 3, and 344 in which packet buffers are allocated in advance for each connection, and a shared pool that can receive TCP data packets of each connection It is.
The shared pool 344 corresponds to the shared storage area.

Next, the operation will be described.
In FIG. 7, a plurality of connections are established between the first terminal device 1 and the second terminal device 2, and data is transmitted from the first terminal device 1 to the second terminal device 2, respectively. Here, a connection between the same terminals will be described, but a plurality of connections by a plurality of terminals may be used instead of the same terminals. In addition, when a connection is established, a pool to be used is set.

  Data transfer of each connection first uses a packet buffer of a pool allocated for each connection. When the packet buffer is depleted, one or more free packet buffers are acquired from the shared pool 344 and used as the free packet buffer of the own pool.

  An example is shown in FIG. Pool 3 343 is used for data transfer of a certain connection, and packet buffers Buff 0-1 to Buff 0-6 of shared pool 344 are used. The packet buffers Buff0-7 to Buff0-9 can be additionally used in the pool 3 343, and can also be used in the pool 1 341 and the pool 2 342. Further, when the packet buffer is released by the response of the delivery confirmation TCP-ACK packet from the second terminal device 2, it may be returned to the shared pool 344.

  As described above, in the data distribution management device according to Embodiment 5 of the present invention, by providing a packet buffer shared by each connection, it is possible to flexibly cope with the communication conditions of each connection. For example, for a connection with a large amount of data or packets, and a connection that takes a long time to respond to a delivery confirmation TCP-ACK packet, it is possible to hold a large amount of data in the data distribution management device, so that the data transfer performance Can be improved.

Embodiment 6 FIG.
In the first to fifth embodiments, after the packet buffer is depleted, no packet is received from the first terminal device 1 even if the packet buffer is recovered by receiving the delivery confirmation TCP-ACK packet from the second terminal device. In this case, the window recovery is not notified to the first terminal device 1, but in the sixth embodiment, even when there is no packet reception from the first terminal device 1, the second terminal device 1 This is notified in response to reception of the delivery confirmation TCP-ACK packet.

  FIG. 9 is an explanatory diagram for explaining the operation of the data distribution management device according to the sixth embodiment of the present invention. In FIG. 9, when the data distribution management device 3 receives the packet DTr5 from the first terminal device 1, the data distribution management device 3 stores it in the packet buffer Buff5 which is the last empty packet buffer, and indicates that the packet buffer is depleted. The size = 0 is notified by the packet buffer AKs5.

  When the data distribution management device 3 receives the packet AKr1 from the second terminal device indicating that the packet DTs1 has been received, the packet buffer Buff1 that holds the TCP data packet is released (that is, empty). , The buffer 34 is recovered. The data distribution management device 3 notifies the first terminal device 1 of the packet AKs6 storing the reception window size value recovered in response to the reception of the packet AKr1.

  Since the first terminal device 1 knows that the reception window has been recovered by the reception of the packet AKs6, the subsequent data is transmitted as the packet DTr6.

  As described above, in the data distribution management device according to the sixth embodiment of the present invention, the reception window recovery is notified in response to the receipt of the delivery confirmation TCP-ACK packet from the second terminal device. Thus, even if the window probe packet is not received by the first terminal device 1, data can be transmitted from the first terminal device 1 immediately after the data distribution management device 3 can resume data transfer. , Transfer time can be shortened.

Embodiment 7 FIG.
In the sixth embodiment, after the packet buffer is depleted, the recovery of the reception window is notified to the first terminal device 1 in response to the recovery. In the seventh embodiment, the recovery amount of the packet buffer has reached a predetermined threshold value. In response to this, a reception window recovery notification is sent.

  FIG. 10 is an explanatory diagram for explaining the operation of the data distribution management device according to the seventh embodiment of the present invention. In this example, the threshold value is when four or more packet buffers are recovered as a trigger for receiving window recovery notification. Upon reception of the packet AKr4, four packet buffers Buff1 to Buff4 are released. The data distribution management device 3 notifies the first terminal device 1 of the reception window recovery by the packet AKs6. Upon receiving the reception window recovery notification, the first terminal apparatus 1 resumes transmission of subsequent data and transmits packets DTr6 to DTr9.

  As described above, in the data distribution management device according to the seventh embodiment of the present invention, the reception of the reception window is notified when the packet buffer vacancy is recovered to a predetermined threshold value or more, so that the first terminal The apparatus can resume transmission of a certain amount of data and further reduce the transfer time.

Embodiment 8 FIG.
In the sixth and seventh embodiments, the recovery notification of the reception window is once after the packet buffer is depleted, but when the packet buffer is temporarily reduced to a predetermined threshold or less and then recovered, this is notified. May be. As a result, for example, when the first terminal device 1 does not exhaust the reception window size of the data delivery management device 3 and interrupts data transmission when it becomes small to some extent, the recovery can be notified quickly.

  As described above, in Embodiments 1 to 8 of the present invention, the case where TCP is used as the communication protocol has been shown. However, it goes without saying that the communication protocol is not limited to this, and flow control similar to TCP is used. Anything corresponding to can be used.

1 is a block diagram showing a data distribution management device according to Embodiment 1 of the present invention. Explanatory drawing for demonstrating operation | movement of the data delivery management apparatus by Embodiment 1 of this invention. Configuration diagram showing a data distribution management apparatus according to Embodiment 2 of the present invention Explanatory drawing for demonstrating operation | movement of the data delivery management apparatus by Embodiment 2 of this invention. Configuration diagram showing a data distribution management apparatus according to Embodiment 3 of the present invention Configuration diagram showing a data distribution management apparatus according to Embodiment 4 of the present invention Configuration diagram showing a data distribution management apparatus according to Embodiment 5 of the present invention Configuration diagram showing a data distribution management apparatus according to Embodiment 5 of the present invention Explanatory drawing for demonstrating operation | movement of the data delivery management apparatus by Embodiment 6 of this invention. Explanatory drawing for demonstrating operation | movement of the data delivery management apparatus by Embodiment 7 of this invention.

Explanation of symbols

3 Data distribution management device 31 Transfer unit 32 Return unit 33 Holding unit 34 Buffer 344 Shared pool

Claims (10)

A transfer unit for transferring the received data packet to the destination;
Storing a segment of the data packet transferred by the transfer unit in a buffer, and in response to receiving a delivery confirmation response packet from the destination, a storage unit that frees the storage area of the segment in the buffer;
A return unit that obtains a reception window size based on the buffer space and a predetermined segment size, and returns the reception window size to the transmission source of the data packet received by the transfer unit;
A data distribution management device comprising:   The data distribution management device according to claim 1, wherein the segment size is a maximum segment size.   The data distribution management device according to claim 1, wherein the segment size is an average segment size.   The return unit obtains a reception window size based on a product of the number of segments that can be stored in the buffer space and a predetermined segment size, and sets the reception window size as a transmission source of the data packet received by the transfer unit. The data distribution management device according to claim 1, wherein the data distribution management device is returned.   The return unit obtains a reception window size based on a product of the number of segments that can be stored in the buffer space, a predetermined segment size, and a predetermined coefficient, and the reception window size is determined based on the data packet received by the transfer unit. The data distribution management apparatus according to claim 1, wherein the data distribution management apparatus returns the data to the transmission source of the data.   The storage unit stores a segment of the data packet transferred by the transfer unit in a shared storage area of a buffer shared by a plurality of connections, and in response to receiving a delivery confirmation response packet from the destination, 2. The data distribution management device according to claim 1, wherein a shared storage area of the segment in the buffer is made empty.   In response to reception of a delivery confirmation response packet from the destination, the return unit obtains a reception window size based on the buffer free space and a predetermined segment size, and the transfer unit determines the reception window size. The data distribution management device according to claim 1, wherein the data distribution management device transmits the received data packet to a transmission source.   The return unit further obtains a reception window size based on the empty buffer and a predetermined segment size in response to reception of a delivery confirmation response packet from the destination, and the reception window size satisfies a predetermined condition. 2. The data distribution management device according to claim 1, wherein the reception window size is transmitted to a transmission source of the data packet received by the transfer unit. A transfer step of transferring the received data packet to a destination;
Storing a segment of the data packet transferred in the transfer step in a buffer, and in response to receiving a delivery confirmation response packet from the destination, a storage step of emptying the storage area of the segment in the buffer;
A return step for obtaining a reception window size based on the free space of the buffer and a predetermined segment size, and returning the reception window size to the transmission source of the data packet received in the transfer step;
A data distribution management method comprising: Corresponding to the reception of the delivery confirmation response packet from the destination, a reception window size is obtained based on the empty space of the buffer and a predetermined segment size, and the reception window size is determined from the transmission source of the data packet received in the transfer step Sending process to send to,
The data distribution management method according to claim 9, further comprising:

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