KR101243502B1 - Data receiving method and apparatus - Google Patents

Abstract

PURPOSE: A data reception method and an apparatus thereof are provided to improve the efficiency of a retransmission request by dynamically changing space between the re-transmission requests. CONSTITUTION: A loss chunk management unit(260) generates a first re-transmission request message. The first re-transmission request message requests transmission of first loss chunk data again. The loss chunk management unit transmits the first re-transmission request message to a data transmission apparatus. A re-transmission request point calculating unit(270) generates a message for requesting the re-transmission of the second loss chunk data and the requested message. The re-transmission request point calculating unit dynamically calculates the re-transmission request point transmitted to the data transmission apparatus. [Reference numerals] (100) Data transmission device; (110) Disk reader; (120) Chuck data transmission unit; (130) Transmission cycle control unit; (140) Loss chunk control unit; (150,250) RTT measurement unit; (200) Data reception unit; (210) Chunk data reception unit; (220) Disk writer; (230) Control information transmission unit; (260) Loss chunk management unit; (261) List writing unit; (263) Packet generation unit; (265) Message type determination unit; (267) Message transmission unit; (270) Re-transmission request point calculating unit; (AA) Chunk data, loss chunk data; (BB) Control information; (CC) Transmission cycle; (DD) Re-transmission request message

Description

Data Receiving Method and Apparatus}

The present invention relates to a data receiving method and apparatus, and more particularly, to a data receiving method and apparatus for dynamically adjusting a retransmission request interval of lost data during data transmission and using a retransmission request message to increase memory usage efficiency. will be.

When a sender sends data to a receiver, packets may be lost during transmission for network conditions and many other reasons. In this case, to recover lost data, the receiver requests the sender to retransmit the data. The time point for transmitting the message requesting retransmission is determined in consideration of the network environment in which the data transmission system is installed and the response and processing speed of the transmission and reception system. If the retransmission request period is calculated without considering these variables, redundant retransmission of data may occur, causing unnecessary use of the network, delayed retransmission packet processing, and ineffective use of the data. Can put process load

According to an exemplary embodiment of the present invention, data that can improve the efficiency of the retransmission request by applying the retransmission request interval optimized for the wired or wireless network environment, and dynamically changing the retransmission request interval in consideration of the network environment It is intended to provide a receiving method and apparatus.

Further, according to an exemplary embodiment of the inventive concept, a retransmission request message is used, which provides the sender with information of the lost data more accurately, while preventing unnecessary use of the memory used for retransmission of the lost data and increasing the use efficiency of the memory. The present invention provides a method and apparatus for receiving data.

According to another exemplary embodiment of the inventive concept, a first retransmission check is performed on the first lost chunk data among the first chunk data received from the data transmission device and requests retransmission of the identified first lost chunk data. A lost chunk manager for generating a request message and transmitting the generated request message to the data transmission device; And a second retransmission request message-a message for requesting retransmission of second lost chunk data among second chunk data to be received from the data transmission apparatus after the first retransmission request message is transmitted. And a retransmission request point calculator which dynamically calculates a retransmission request point to be transmitted in advance.

Meanwhile, according to another exemplary embodiment of the inventive concept, the method may further include: verifying first lost chunk data among first chunk data received from a data transmission device; Generating and transmitting a first retransmission request message requesting retransmission of the identified first lost chunk data to the data transmission apparatus; And a second retransmission request message-a message for requesting retransmission of second lost chunk data among second chunk data to be received from the data transmission apparatus after the first retransmission request message is transmitted. Dynamically calculating a retransmission request time point to be transmitted to the data in advance; may be provided with a data receiving method comprising a.

According to one or more example embodiments of the inventive concept, a retransmission request interval optimized for a network environment in which a data transmission system is installed is dynamically calculated in advance, a type of a retransmission request message for recovering lost data is defined, Sending retransmission request messages at dynamically calculated intervals can improve network utilization, retransmission efficiency, and computing resource utilization.

Further, according to one or more exemplary embodiments of the inventive concept, when the data transmission device receives a retransmission request message that includes information about lost data, the data transmission device chunks the data that has been received from the retransmission request message. By checking in units and revoking the corresponding data in the memory, the memory utilization can be increased.

1 is a diagram illustrating a high speed data transmission / reception system according to an exemplary embodiment of the inventive concept;
2 is a diagram illustrating a series of processes for requesting retransmission of lost chunk data;
3 is a diagram illustrating a series of processes for requesting retransmission of lost chunk data using a new transmission period;
4 is a diagram for describing a memory structure used when a disk reader loads data of a file into a memory;
FIG. 5 is a diagram for describing a method of determining, by a lost chunk controller, a chunk data of which reception has been completed using a retransmission request message; FIG.
6 is a view for explaining a memory structure used in the data receiving apparatus;
7 is a diagram illustrating an example in which a plurality of sublist packets are generated from a first lost chunk list;
8 is a diagram illustrating a format of a sublist packet or a list packet generated by a packet generator according to an exemplary embodiment of the inventive concept;
FIG. 9A illustrates one file block including 30 chunks of a memory structure used by the chunk data transmitter;
9B illustrates an example of a lost chunk list and subpackets;
9C illustrates an example of a lost chunk list and a list packet;
10 is a view for explaining an example of a process in which a packet generation unit overlaps lost chunk data according to an exemplary embodiment of the inventive concept; and
11 and 12 are flowcharts illustrating a data receiving method according to an exemplary embodiment of the inventive concept.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween.

Where the terms first, second, etc. are used herein to describe components, these components should not be limited by such terms. These terms have only been used to distinguish one component from another. The embodiments described and exemplified herein also include their complementary embodiments.

In addition, when it is mentioned that a first element (or component) is operated or executed on a second element (or component), the first element (or component) is a second element (or component). It is to be understood that the operation or execution in the environment in which the operation or the execution is performed or the operation or execution is performed through direct or indirect interaction with the second element (or component).

It is to be understood that when an element, component, apparatus, or system is referred to as comprising a program or a component made up of software, it is not explicitly stated that the element, component, (E.g., memory, CPU, etc.) or other programs or software (e.g., drivers necessary to drive an operating system or hardware, etc.)

It is also to be understood that the elements (or components) may be implemented in software, hardware, or any form of software and hardware, unless the context clearly dictates otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms "comprises" and / or "comprising" used in the specification do not exclude the presence or addition of one or more other elements.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In describing the specific embodiments below, various specific details are written to more specifically explain and help understand the inventive concept. However, a person skilled in the art that can understand the inventive concept can recognize that it can be used without these various specific details. In some cases, it is mentioned in advance that parts of the invention which are commonly known in the description of the inventive concept and which are not highly related to the invention are not described in order to prevent confusion for no reason.

1 is a diagram illustrating a high speed data transmission / reception system according to an exemplary embodiment of the inventive concept.

Referring to FIG. 1, the high speed data transmission / reception system includes a data reception device 200 including a data transmission device 100 and a data retransmission request device 240.

The data transmission apparatus 100 may include a disk reader 110, a chunk data transmitter 120, a transmission cycle controller 130, a lost chunk controller 140, and a round trip time (RTT) measurer 150. have.

The disk reader 110 may read a file recorded on a recording medium (not shown) such as a hard disk drive (HDD) in file block units, load the file in a memory (not shown), and record the data in chunks. In the present specification, 'chunk' is a data transmission unit having a predetermined size, and refers to a pure data portion excluding a header in a transmitted data packet. 'Chunk data' is data recorded in chunks. A 'file block' is a unit of memory used to record a file for transferring. The file block has a certain positive multiple of the chunk size.

The chunk data transmitter 120 may transmit the file block in which data is recorded to the data receiving apparatus 200 in chunk units.

The transmission period controller 130 periodically receives control information from the control information transmitter 230 of the data receiving apparatus 200, and transmits a transmission period (td, delay time) between chunk data based on the received control information. I can regulate it. When the chunk data includes the first chunk data and the second chunk data, the transmission period means a term from transmitting the first chunk data to transmitting the second chunk data. In addition, the transmission period controller 130 may periodically transmit the adjusted transmission period based on the control information to the lost chunk manager 260 in the acknowledgment of the control information.

The chunk data transmitter 120 may transmit the chunk data to the data receiving apparatus 200 with reference to the transmission period adjusted by the transmission period controller 130. Therefore, the data rate of the chunk data transmitter 120 may be changed according to the transmission period between the chunk data.

The lost chunk control unit 140 receives the lost chunk data (ie, lost packets) from the lost chunk manager 260 while transmitting the chunk data, and the lost chunk data and the received chunk data are received from the lost chunk data. You can check the completed chunk data.

The lost chunk control unit 140 may request the disk reader 110 to retransmit the lost chunk data while providing the identified information of the lost chunk data to the disk reader 110. As a result, the disc reader 110 reads the lost chunk data corresponding to the information of the lost chunk data from the recording medium and writes them to the memory in chunk units, and the chunk data transmitter 120 chunks the lost chunk data in chunk units. The data receiver 210 may retransmit the data. The chunk data transmitter 120 may retransmit the lost chunk data in the order of a unique number of the lost chunk data. The unique number of the lost chunk data will be described later with reference to FIG. 4.

When the connection between the data transmission device 100 and the data reception device 200 is established, the RTT measurement unit 150 exchanges the RTT measurement packet periodically from the start of transmission of the chunk data to the end of the transmission to obtain an RTT at the present time. .

The data receiving apparatus 200 may include a chunk data receiver 210, a disc writer 220, a control information transmitter 230, a data retransmission request apparatus 240, and an RTT measuring unit 250.

The chunk data receiver 210 stores the chunk data received from the chunk data transmitter 120 in a file block.

The disc writer 220 may record the received file block on a recording medium (not shown). For example, when one file block is divided into ten chunks, when ten chunk data are stored in the file block, the disc writer 220 determines that the file block is a received file block.

The control information transmitter 230 may periodically transmit the control information of the data receiving apparatus 200 to the transmission period controller 130. The control information may be information shared by the data transmission apparatus 100 and the data receiving apparatus 200 for file transmission.

The control information includes information such as a file name of a file to be transmitted, a file size, a number of streams, a disk buffer size, a total number of blocks, an IP address, a port information, and a session ID. When files are transferred in parallel Transmission Control Protocol (TCP) streams, the number of streams is the maximum number of connections in the stream that can be used for file transfers, and the disk buffer size is the file blocks allocated to the buffers for writing data to the record carrier. The size of, IP address is the IP address used for data transmission, port information is the port information used for data transmission, session ID is the ID of each stream.

The data retransmission request apparatus 240 may operate as a request for retransmission of lost data from the lost chunk manager 260 and the retransmission request time calculator 270.

The lost chunk manager 260 may transmit the lost chunk data (hereinafter, referred to as "lost chunk data") among the received chunk data to the lost chunk controller 140. In more detail, the lost chunk manager 260 checks the information of the lost chunk data among the chunk data received from the chunk data transmitter 120 to request retransmission of the lost chunk data, and checks the lost chunk data. The retransmission request message may be generated using the information and transmitted to the lost chunk controller 140. The information of the lost chunk data may be a unique number of the lost chunk data, that is, identification.

The retransmission request point calculator 270 may calculate, in advance, the next retransmission request point for generating a next retransmission request message at a point in time of generating and transmitting the retransmission request message for the first time.

The retransmission request timing calculator 270 pre-remits the retransmission request timing by using the RTT measured by the RTT measurement unit 250, the transmission period received from the transmission period controller 130, and the number of lost chunk data collected for a predetermined period. Can be calculated. Therefore, the retransmission request point calculator 270 dynamically calculates a retransmission request point in advance according to a network environment, and the lost chunk manager 260 may collect lost chunk data collected for a predetermined period when the retransmission request point arrives in advance. It may generate a retransmission request message for the lost chunk control unit 140.

When the connection between the data transmission device 100 and the data reception device 200 is established, the RTT measurement unit 250 periodically exchanges RTT measurement packets from the start of transmission of the chunk data to the end of the transmission to obtain an RTT at the present time. . The RTT measured by the RTT measuring unit 250 may be used when calculating the retransmission request interval in the lost chunk manager 260.

Hereinafter, an operation of calculating a retransmission request point in time by the retransmission request point calculator 270 according to an exemplary embodiment of the inventive concept will be described in detail with reference to FIGS. 2 and 3.

2 is a diagram illustrating a series of processes for requesting retransmission of lost chunk data.

Referring to FIG. 2, the chunk data transmitter 120 starts the transmission of the first chunk data at a point S1 (①), and the chunk data receiver 210 is the first first of the first chunk data at the point R1. Receive chunk data. The chunk data transmitter 120 may transmit the first chunk data based on the first transmission period t _d1 calculated by the transmission period controller 130, that is, at intervals of the first transmission period. The time until the first first chunk data is transmitted and received may be RTT / 2.

The lost chunk manager 260 waits for a predetermined initial value K hours from R1 when the first chunk data is first received, that is, the first chunk data received for K hours at a time R2 (R2 = R1 + K). The first lost chunk data can be checked by examining. The lost chunk manager 260 may generate a first retransmission request message requesting retransmission of the identified first lost chunk data and transmit it to the lost chunk controller 140 (②). The time until the first retransmission request message reaches the lost chunk controller 140 may be RTT / 2.

In addition, when generating and transmitting the first retransmission request message, the retransmission request timing calculator 270 may calculate the retransmission request timing to be transmitted by generating the second retransmission request message in advance at the R2 time point. The second retransmission request message is a message for requesting retransmission of the second lost chunk data among the second chunk data to be received from the chunk data transmitter 120 from the R2 time point after the first retransmission request message is transmitted.

The retransmission request timing calculator 270 may calculate the next retransmission request timing in advance by using Equation 1 below.

In Equation 1, T2 is a calculated retransmission request time point, T1 is a time point when the first retransmission request message is generated, RTT is the most recent round trip time measured by the RTT measurement unit 250, and N is the time point at R2. The number of confirmed first lost chunk data, t _d1, is the first transmission period when the chunk data transmitter 120 retransmits the first lost chunk data. In Equation 1, T1 is R2 in FIG. 2, and T2 is R4.

When the retransmission request time is calculated by Equation 1, the lost chunk manager 260 generates a first time at a time T2 or R4 after a time elapsed from T1 (or R2) by (RTT + (N × t _d1 )). 2 may be generated and sent to the lost chunk control unit 140. At this time, the lost chunk manager 260 may be missing chunk data among the second chunk data received from the R2 time point to the R3 time point, and second chunk data (or the first lost chunk data received from the R3 time point to the R4 time point). May generate a second retransmission request message from the lost chunk data.

The retransmission request time point calculated in Equation 1 includes a time (RTT / 2) at which the first retransmission request message is transmitted to the lost chunk controller 140, and the N first lost chunk data in the chunk data transmitter 120. It is the result of adding up the time required to transmit all (N × t _d1 ) and the time until the last data of the first lost chunk data arrives to the chunk data receiver 210 (RTT / 2). The use of Equation 1 by the retransmission request point calculator 270 is to prevent the chunk data transmitter 120 from repeatedly transmitting the first lost chunk data. In other words, [Equation 1] is for optimizing the time from the retransmission request time calculation unit 270 to generate and transmit the second retransmission request message to be transmitted next, and all the second lost chunk data previously requested Considering the time required to arrive by the chunk data receiving unit 210 is retransmitted.

The disk reader 110 records the first lost chunk data in the chunk unit based on the received first retransmission request message in the chunk unit, and the chunk data transmitter 120 is the first of the first lost chunk data at the time S2. The data starts to be retransmitted, and the first lost chunk data can be retransmitted during N × t _d1 (③).

The chunk data transmitter 120 may transmit the last first lost chunk data at time S3 (④), and the chunk data receiver 210 may receive the last first lost chunk data at time R4.

On the other hand, if the second retransmission request message transmitted from R4 is lost (⑤), the lost chunk manager 260 retransmits the second retransmission request message to the lost chunk controller 140 at a time point R5 from R4. can do. This is because if the chunk data receiving unit 210 does not receive the second lost chunk data included in the second retransmission request message from the time point R4 at which the second retransmission request message is transmitted (R4) (6). This is because the lost chunk manager 260 may determine that the second retransmission request message transmitted at the R4 time point is lost. Accordingly, the lost chunk manager 260 retransmits the second retransmission request message immediately at R5 without additionally waiting for N × t _d1 time, or the third lost chunk lost among the third chunk data received during R5 at R4. A new third retransmission request message including the data and the second lost chunk data may be generated and transmitted to the lost chunk control unit 140 (⑦).

3 is a diagram illustrating a series of processes for requesting retransmission of lost chunk data using a new transmission period.

Referring to FIG. 3, a process (① to ③) of retransmitting the first lost chunk data while the first chunk data starts to be transmitted is the same as the process (① to ③) of FIG. If a new transmission period t _d2 is calculated at time S3 based on the received control information, the transmission period controller 130 may transmit the new transmission period t _d2 to the lost chunk manager 260 (④).

The lost chunk manager 260 waits for the next retransmission request time calculated by Equation 1, or while the first lost chunk data is received from the chunk data transmitter 120, the transmission period controller 130. A new transmission period (t _d2 , new Delay Time) can be received from (R5). In this case, the retransmission request timing calculator 270 may recalculate the retransmission request timing in consideration of the new transmission period t _d2 . That is, the retransmission request time calculation unit 270 is scheduled to generate a second retransmission request message after waiting until R4 according to the retransmission request time calculated at the R2 time point, and a new transmission period t _d2 at the time R5. When receiving the Equation (2) and [Equation 3] can be calculated at the time of the new retransmission request R5.

In [Equation 2] and [Equation 3], M is the number of the first lost chunk data re-received from the chunk data transmitter 120 in the transmission period (t _d1 ), T _nd is a new transmission period (t _d2) ) Is received, T _c1 is the first received lost chunk data of the first lost chunk data received, T3 is the calculated retransmission request time, t _d2 is a new transmission period. In Equations 2 and 3, T _c1 is R3 in FIG. 3, T _nd is R5, and T3 is R6.

Referring to FIG. 3, the chunk data transmitter 120 transmits the first lost chunk data in a previous transmission period t _d1 from S2 to S6 (that is, R3 to R5) that transmitted the first first chunk data. M retransmissions. Therefore, since the retransmission request timing calculator 270 knows T _c1 (or R3) and T _nd (or R5), it is possible to calculate M using Equation 2.

When M is calculated, the retransmission request time calculator 270 may know the number NM of first lost chunk data to be transmitted by the chunk data transmitter 120 using a new transmission period t _d2 . Accordingly, the retransmission request time calculation unit 270 newly calculates the retransmission request time T3 or R6 by using (NM), R5 (or T _nd ) and a new transmission period t _d2 which are already known at the time of R5. can do. 3 illustrates an example in which the new transmission period t _d2 is smaller than the previous transmission period t _d1 . If the new transmission period t _d2 is larger than the previous transmission period t _d1 , R6 is greater than R4. Have

Therefore, when a new transmission period t _d2 is received, the lost chunk manager 260 sends a second retransmission request message from R5 (or T _nd ) at R6 at a time elapsed by ((NM) × t _d2 ). It can be generated and transmitted to the lost chunk controller 140 (⑤). The chunk data transmitter 120 starts to retransmit the second lost chunk data at step S7 (6).

Hereinafter, a memory structure used in the data transmission apparatus 100 and the data receiving apparatus 200 will be described with reference to FIGS. 4 to 6.

As described above, the lost chunk manager 260 may generate a retransmission request message and request the retransmission of the lost chunk data to the data transmission apparatus 100. Before the detailed description related to the retransmission request message, a memory used by the data transmission apparatus 100 and the data reception apparatus 200 will be described.

First, the memory use of the data transmission device 100 will be described. Computing memory used for data transfer is a limited resource, and memory operation and reuse are important issues, especially in systems that handle large files. In an exemplary embodiment of the present invention, as a memory usage method, a part of data of a file to be transmitted is loaded into a memory and then transmitted, and the disk reader 110 loads data into a memory in units of file blocks. The chunk data transmitter 120 transmits the data in the memory in chunk units. Loading the data into the memory prior to transferring the chunk data can prevent the slowdown caused by reading the file directly from the recording medium in the middle of transferring the chunk data.

4 is a diagram for describing a memory structure used when the disk reader 110 loads data of a file into a memory.

Referring to FIG. 4, data of a file to be transmitted includes S file blocks, each file block may include K chunk data, and the last file block may have K chunk data of K or less according to the file size. Therefore, it may include K '(K'≤ K) chunk data. The unique number of the chunk data may inform the position of the file block in which the chunk exists (= ID of the file block (S-1) K) and information K 'indicating the number of chunks in the file block. . Hereinafter, the unique number of the chunk data is referred to as the chunk data ID.

As shown in FIG. 4, the disk reader 110 assigns IDs (ie, unique numbers) from the first chunk data of the first file block (file block 1) in order, thereby allowing the chunk data to be changed according to the range of IDs. Make sure you know which chunk is in the block.

Meanwhile, in the exemplary embodiment of the present invention, the lost chunk controller 140 may use the retransmission request message received from the lost chunk manager 260 as a method for knowing the received chunk data. The retransmission request message is composed of IDs of chunk data (ie, lost chunk data) that have not been received, which means that all but the lost chunk data are received. Therefore, the lost chunk controller 140 may determine (or confirm) whether to receive the chunk data using the IDs of the lost chunk data described in the retransmission request message.

When the chunk data received by the lost chunk controller 140 is determined, the lost chunk controller 140 may immediately delete the received chunk data from the memory in which the chunk data are loaded. Unlike the disk reader 110 allocating memory in units of file blocks, the lost chunk control unit 140 also rapidly releases (ie, deletes chunk data) the memory in chunk units smaller than the file blocks and recycles the memory. It means to be able to.

FIG. 5 is a diagram for describing a method in which the lost chunk controller 140 determines the received chunk data by using a retransmission request message.

In FIG. 5, the lost chunk list forming the retransmission request message includes information of lost chunk data having IDs of 2, 3, 9, 14, 15, 20, and 25, respectively. The lost chunk list may be created by the lost chunk manager 260 or the list generator 261 to be described later.

The lost chunk controller 140 may recognize that chunk data having an ID of 2, 3, 9, 14, 15, 20, and 25 has been lost from the received retransmission request message. As a result, the lost chunk controller 140 includes chunk data having IDs of 4, 5, 6, 7 and 8 between 3 and 9, and chunk data corresponding to 10, 11, 12, and 13 between 9 and 14. It may be determined that it has been received. The same is true for chunk data between 16 and 20 and chunk data between 20 and 25.

The lost chunk controller 140 may release the memory on which the chunk data has been loaded based on the IDs of the chunk data determined to have been received. Therefore, while conventionally performing memory release at a time when a certain amount of memory is secured (that is, when the amount of memory corresponding to one file block is released), the present embodiment uses chunk units for fast memory reuse. Memory cancellation is performed, and the disk reader 110 may read new data in units of file blocks and load them into the memory whenever the size of the canceled memory is secured by file blocks.

FIG. 6 is a diagram for describing a memory structure used in the data receiving apparatus 200.

Referring to FIG. 6, the structure of the memory used in the data receiving apparatus 200 is similar to that used in the data transmitting apparatus 100 as shown in FIG. 4. The disc writer 220 loads the chunk data at a position corresponding to the ID of the chunk data among the file blocks in the order in which the chunk data is received, and records the chunk data on the recording medium when the file blocks are all filled. However, the data transmission apparatus 100 loads the chunk data using all available memories before transmitting the chunk data, while the data receiving apparatus 200 selects a memory to load the chunk data while the chunk data is received. It is different from each other. Therefore, the amount of memory used in the data receiving apparatus 200 does not utilize all of the available memory, and thus the amount of memory used may be relatively small.

Hereinafter, with reference to FIGS. 7 to 9, a series of operations in which the lost chunk manager 260 generates a retransmission request message according to an exemplary embodiment of the present invention will be described.

In order to compose the retransmission request message, the lost chunk manager 260 may include a list generator 261, a packet generator 263, a message type determiner 265, and a message transmitter 267.

The list generator 261 may check the memory in chunk units, and may determine whether the first chunk data is received according to whether the received first chunk data is loaded at a corresponding position in the memory. Since the first chunk data of the ID described in the file block of the memory as shown in FIG. 6 is received, the size of the file block used by the chunk data transmitter 120 and the chunk data receiver 210 is the same. The list generator 261 may check the first lost chunk data. That is, the list creation unit 261 may determine that the first chunk data of the unidentified ID in the file block is lost, and create the first lost chunk list by combining the determined IDs of the first lost chunk data. IDs of the first lost chunk data mean lost chunk information, respectively.

The packet generator 263 may generate a plurality of sublist packets by dividing the first lost chunk list into a plurality of sublists based on a maximum transmission unit (MTU). MTU is the maximum size of a transport packet used in a network communication environment.

7 is a diagram illustrating an example in which a plurality of sublist packets are generated from a first lost chunk list.

Referring to FIG. 7, the packet generator 263 divides the first lost chunk list into a plurality of sublists having a size smaller than the MTU, and adds header information to the plurality of sublists to be smaller than or equal to the MTU. It is possible to generate sublist packets of size. The plurality of sublist packets may be transmitted to the lost chunk controller 140 in MTU units. In addition, the packet generation unit 263 may generate one list packet when the size of the sum of the first lost chunk list and the header information is MTU or less.

8 is a diagram illustrating a format of a sublist packet or a list packet generated by the packet generator 263 according to an exemplary embodiment of the inventive concept.

Referring to FIG. 8, the sublist packet or list packet may include a header including an ID, a message type (Msg Type) and a maximum number (Max No), and a payload including missing chunk information. The ID is the unique identification information of the sublist packet or the list packet, the message type is the message type determined by the message type determining unit 265, and the maximum number is the last in the chunk data receiving unit 210 when the checking operation of the lost chunk data is started. It is the ID of the chunk data that has arrived, and the lost chunk information is the IDs of the lost chunk data included in one sublist. The maximum number may be described in all types of messages and is used when the message types are types C and D to be described later. The packet generator 263 may write ID, message type, and lost chunk information in the corresponding packet.

The message type determination unit 265 may determine a message type of the plurality of sublist packets according to a position where the plurality of sublist packets belong to the first lost chunk list, and may write the determined message type in the plurality of sublist packets. have.

If the first sublist packet, which is one of the plurality of sublist packets, is the first packet of the first lost chunk list, the message type determination unit 265 may determine the message type of the first sublist packet as type A. .

Also, if the first sublist packet is one of the sublist packets except for the first and the last of the first lost chunk list, the message type determination unit 265 may determine the message type of the first sublist packet as type B.

In addition, if the first sublist packet is the last packet of the first lost chunk list, the message type determination unit 265 may determine the message type of the first sublist packet as type C.

In the plurality of sublist packets generated from one first lost chunk list, one type A and one type C exist, and one or more type B may exist.

When the packet generator 263 is able to generate one list packet because the size of the first lost chunk list is small, the message type determiner 265 may determine the message type of the list packet as type D. That is, when the retransmission request message is generated as one list packet, the message type determination unit 265 may determine the message type of the list packet as type D.

The message transmitter 267 may transmit the plurality of sublist packets including the message type to the lost chunk controller 140 as the first retransmission request message. The first retransmission request message means a bundle of a plurality of sublist packets. Accordingly, the transmission of the first retransmission request message may mean that a plurality of sublist packets are transmitted.

Meanwhile, the lost chunk control unit 140 having received the plurality of sublist packets in which the message type is described determines the received data among the first chunk data with reference to the message type, and receives the received chunk from the memory used when transmitting the first chunk data. Data determined to be completed can be deleted. However, this memory cancellation may be performed when the plurality of sublist packets are received in the lost chunk controller 140 in order.

 [Table 1] is a table listing characteristics or information of each message type.

Message type Features or information Type A A packet of the first sublist among the plurality of sublists divided from the lost chunk list.
Only one exists in one lost chunk list.
-Among the chunk data having an ID smaller than the ID of the first lost chunk data of the sublist packet, the chunk data that have undergone the lost chunk checking operation is completed. Type B A packet of sublists except the first and last sublists among the plurality of sublists divided from the lost chunk list.
More than one in the missing chunk list. Type C A packet of the last sublist among the plurality of sublists divided from the lost chunk list.
Only one exists in one lost chunk list.
-Among the chunk data having an ID larger than the ID of the lost chunk data positioned at the end of the sublist packet, the chunk data of the maximum ID that has undergone the lost chunk checking operation is all received. Type D -Since the size including the lost chunk list and the header information is less than the MTU, it indicates that the list packet is generated as it is from one lost chunk list.
Contains both type A and type C information

In [Table 1], the lost chunk checking operation means checking the IDs of the received chunk data and determining that the chunk data corresponding to the missing ID is lost.

Hereinafter, the information provided by each message type will be described in detail with reference to FIGS. 9A to 9C.

FIG. 9A illustrates one file block 910 including 30 chunks of a memory structure used by the chunk data transmitter 120. FIG. 9B illustrates a lost chunk list 920 and subpackets 931 and 932. 933 is a diagram illustrating an example of a lost chunk list 920 and a list packet 940.

Referring to FIG. 9A, since one file block 910 is composed of 30 chunks, K = 30, and IDs of chunk data described in each chunk are 1 to 30. The chunk data transmitter 120 transmits the file block 910 to the chunk data receiver 210 in chunk units, and the chunk data receiver 210 may receive the chunk data.

The list generator 261 may collect IDs of the lost chunk data by using the received information of the chunk data. When the list creation unit 261 reaches the retransmission request time calculated by the retransmission request time calculation unit 270, the list creating unit 261 includes IDs of the lost chunk data collected for a predetermined period (for example, between R2 and R4 in FIG. 2). The lost chunk list 920 may be created using the. According to the lost chunk list 920, it can be seen that chunk data having IDs of 2, 3, 9, 14, 15, 20, and 25 among the chunk data included in the file block 910 are lost chunk data.

The packet generator 263 divides the lost chunk list 920 into first to third sublists 921, 922, and 923 based on the MTU, and first to third sublists 921, 922, and 923. ) May generate first to third sublist packets 931, 932, and 933 respectively.

The message type determination unit 265 determines the message types of the first to third sublist packets 931, 932, and 933 as type A, type B, and type C, respectively, to determine the first to third sublist packets ( 931, 932, 933).

When the packet generator 263 generates the lost chunk list 920 as one list packet 940 as it is, the message type of the list packet is determined as type D. The list packet 940 means that the MTU is defined as a size capable of recording seven or more chunk data.

All the message types make it possible to know that the chunk data of the missing ID is the received chunk data if there is a missing ID among the IDs consecutively listed in the sublist packet or the list packet. For example, since 3 and 9 are continuously described in the first sublist packet 931, the lost chunk control unit 140 has chunk data having 4, 5, 6, 7, 8 between 3 and 9 as IDs. It can be seen that the reception is completed by the chunk data receiving unit 210.

In addition, the lost chunk control unit 140 having received the first sublist packet 931 describing the type A checks the smallest ID among the IDs described in the first sublist packet 931, and checks the smallest of the chunk data. Chunk data having an ID smaller than the small ID (for example, 2) may be determined to have been received. For example, there is one first sublist packet 931 in which type A is described, and the second chunk data is located at the beginning of the first sublist packet 931. Accordingly, the first sublist packet 931 may provide the lost chunk control unit 140 with information indicating that the first chunk data first confirmed in the lost chunk checking operation is also received. The lost chunk controller 140 may delete chunk data having 1, 4, 5, 6, 7, 8 as IDs from the file block 910.

This example requires the assumption that the lost chunk checking operation started with chunk data of file block 910. The starting point of the lost chunk checking operation may vary depending on the implementation method, and may be immediately after the ID of the first chunk data of the file block in which reception is not completed and the consecutive chunk data in which reception is completed.

There may be a plurality of second sublist packets 932 describing the type B according to the size of the lost chunk list 920. Accordingly, the lost chunk controller 140 may obtain information that there is more lost chunk data before the ID described at the beginning of the received second sublist packet 932 and after the ID described at the end. In addition, the lost chunk controller 140 receiving the second sublist packet 932 recognizes that the chunk data having 16, 17, 18, and 19 between 15 and 20 as an ID is received by the chunk data receiver 210. Can be. The lost chunk controller 140 may delete chunk data having 16, 17, 18, and 19 as IDs from the file block 910.

The lost chunk control unit 140 having received the third sublist packet 933 describing the type C confirms the largest ID among the IDs of the lost chunk data described in the third sublist packet 933, and then checks the third sublist packet. It is determined that the chunk data up to the maximum number Max No, which is data of an ID larger than the largest ID described in the list packet 933, is received. For example, there is one third sublist packet 933 described with type C in the lost chunk list 920, and is larger than 25 because chunk number 25 is located at the end of the third sublist packet 933. The lost chunk controller 140 may provide information indicating that the chunk data having the ID has been received up to the last chunk data of the lost chunk checking operation. 9A and 9B, when the lost chunk list 920 is created after the lost chunk checking operation is performed from the file block 910 to the chunk data 29, the third sublist packet 933 is the maximum number (Max). If No) is 29, the chunk data having '26, 27, 28, 29 'as an ID may be additionally provided to the lost chunk controller 140. The lost chunk controller 140 may delete chunk data having '26, 27, 28, 29 'as an ID from the file block 910.

The list packet 940 describing the type D may provide both the information provided by the type A and the type C. Therefore, the lost chunk control unit 140 having received the list packet 940 having type D described therein is the maximum number of IDs other than the IDs described in the list packet 940 among the chunk data from the type D described in the list packet 940. All data having chunk data having an ID up to (Max No) may be determined to have been received.

On the other hand, the operation of canceling the memory described above with reference to FIGS. 9A to 9C, that is, deleting the chunk data received from the file block 910 is performed by the first to third sublist packets 931, 932, and 933. It may be performed when the lost chunk controller 140 is continuously received in order according to the IDs of the respective sublist packets 931, 932, and 933. That is, when the order of arrival of the first to third sublist packets 931, 932, and 933 is not constant, it is not possible to confirm whether or not the chunk data having the ID of '10, 11, 12, 13 'is received. Cases may occur.

In an exemplary embodiment of the inventive concept, to solve this problem, that is, to correctly obtain information on the received chunk data from the first to third sublist packets 931, 932, and 933. Redundant application of lost chunk data can be used. That is, if the message types of the first to third sublist packets 931, 932, and 933 are Type A, Type B, and Type C, respectively, the packet generation unit 263 may include first and second types having Type A and Type B; The IDs listed at the end of the second sublist packets 931 and 932 may be duplicated at the beginning of the second and third sublist packets 932 and 933 having type B and type C, respectively.

The lost chunk controller 140 may obtain information on the received chunk data by using only the IDs described in the plurality of sublist packets even when the plurality of sublist packets to which the overlapping application scheme is applied are randomly received. . Therefore, when applying the redundant application method, the lost chunk control unit 140 can accurately know all the information of the received chunk data provided by the lost chunk list, and by obtaining more information per single packet, Can quickly free up memory.

10 is a diagram for explaining an example of a process in which the packet generator 263 overlaps lost chunk data according to an exemplary embodiment of the inventive concept.

Referring to FIG. 10, the packet generation unit 263 duplicates the ID '9' of the lost chunk data described at the end of the first sublist 1010 at the beginning of the second sublist 1020, and the second sublist. The ID '15' described at the end of the list 1020 is duplicated at the beginning of the third sublist 1030. The packet generator 263 may generate the first to third sublists 1010, 1020, and 1030 as the first to third sublist packets 1011, 1021, and 1031, respectively.

When the lost chunk controller 140 receives the first to third sublist packets 1011, 1021, and 1031 in a random order, the chunk data having an ID of 9 is lost because '9' is repeatedly described. The chunk data having IDs between 9 and 14 may know that reception is completed. In addition, the lost chunk controller 140 may recognize that the chunk data having an ID of 15 is lost since the '15' is repeatedly described, and that the chunk data having the IDs between 15 and 20 are completed.

11 and 12 are flowcharts illustrating a data receiving method according to an exemplary embodiment of the inventive concept.

The data transmission device and the data reception device performing the data reception method of FIGS. 11 and 12 may be the data transmission device 100 and the data reception device 200 described with reference to FIG. 1, thus, a message retransmission request and a message. Detailed descriptions related to types, retransmission request messages, etc. will be omitted.

First, referring to FIG. 11, the data transmission device may transmit first chunk data recorded in chunk units in a file block to the data reception device in operation S1100. In operation S1100, the data transmission apparatus transmits unique numbers of the first chunk data, that is, IDs.

The data receiving apparatus may record the received first chunk data on the recording medium (S1105).

The data receiving device may collect the first lost chunk data while the first chunk data are sequentially received (S1110). The data receiving apparatus may collect the first lost chunk data missing from the IDs of the received first chunk data.

When the definition time K has elapsed since the first time the first chunk data is received in step S1100, the data receiving apparatus may create a first lost chunk list from the first lost chunk data collected for K hours ( S1115).

The data receiving apparatus may generate a plurality of sublist packets by dividing the first lost chunk list into a plurality of sublists based on the MTU, and may determine a message type of each sublist packet (S1120). The message type may be determined according to a location where a plurality of sublist packets belong to the first lost chunk list, and may have types A to D, as described with reference to FIGS. 9A to 9C.

In operation S1125, the data receiving apparatus may transmit the plurality of sublist packets generated in operation S1120 as a first retransmission request message.

When step S1125 is performed, the data receiving apparatus calculates in advance a retransmission request time point for transmitting a next retransmission request message (S1130). In operation S1130, the data receiving apparatus may calculate a retransmission request time using the method described with reference to [Equation 1].

In addition, the data transmission apparatus that has received the first retransmission request message may include a first received reception from the lost chunk information (that is, the IDs of the first lost chunk data) described in the plurality of sublist packets forming the first retransmission request message. Chunk data can be confirmed (S1135).

In operation S1140, the data transmission apparatus may delete the first chunk data, from which the reception of the first chunk data transmitted in step S1100, has been received, in the corresponding memory area. That is, the data transmission device may delete the first chunk data of the first chunk data described in the memory in chunk units.

In operation S1140, the data transmission device may write the first lost chunk data in the empty memory area (S1145).

The data transmission device may transmit the first lost chunk data and the second chunk data described in the memory to the data reception device in operation S1145 (S1150). The second chunk data is chunk data transmitted after the first lost chunk data are transmitted. For example, the second chunk data may be data transmitted from the time S3 of FIG. 2.

The data receiving apparatus may record the second lost chunk data and the second chunk data on the recording medium (S1155).

The data receiving device may collect second lost chunk data from the chunk data recorded in step S1155 (S1160).

Steps S1150 to S1160 may be continuously performed until the retransmission request time calculated in step S1130 is reached.

When the retransmission request time calculated in step S1130 is reached (S1165-N), the data reception device may generate a second retransmission request message (S1170). Step S1170 operates similarly to steps S1110 to S1120.

The data receiving apparatus transmits the second retransmission request message generated in operation S1170 to the data transmission apparatus (S1175), and calculates the next retransmission request time point in advance with reference to [Equation 1] (S1180).

The data transmission device that receives the second retransmission request message in operation S1175 may perform operations similar to operations S1135 to S1150 to transmit second lost chunk data to the data reception device.

When the second lost chunk data is received from the data transmission apparatus (S1185-Y), the data receiving apparatus records the second lost chunk data on the recording medium (S1190).

On the other hand, if there is no second lost chunk data received from the data transmission apparatus (S1185-N), the data receiving apparatus returns the second lost chunk data from the time when the second retransmission request message is transmitted in step S1175 until the RTT elapses. If not received (S1195-Y), the second retransmission request message may be retransmitted or the third retransmission request message may be transmitted (S1197). The third retransmission request message indicates retransmission of the third lost chunk data and the second lost chunk data that are not received among the third chunk data when there are third chunk data received while waiting for the RTT to elapse. It may be a requesting message.

Referring to FIG. 12, steps S1200 to S1260 are the same as steps S1100 to S1160 described with reference to FIG. 11 and thus will be omitted.

If a new transmission period is received from the data transmission device while collecting the second lost chunk data in step S1260 (S1265), the data receiving device M is the number of second lost chunk data re-received from the data transmission device in the previous transmission period. It can be calculated using [Equation 2] (S1270). The new transmission period is the interval at which the data transmission device transmits the chunk data.

The data receiving apparatus calculates a new retransmission request time point for transmitting the second retransmission request message using the calculated M and Equation 3 (S1275).

When the retransmission request time point recalculated in step S1275 is reached (S1280-Y), the data reception device may generate a second retransmission request message and transmit it to the data transmission device (S1285 and S1290). In operation S1285, the second retransmission request message may be generated using the same method as that of generating the first retransmission request message.

The data transmission device that receives the second retransmission request message in operation S1175 may perform operations similar to operations S1135 to S1150 to transmit second lost chunk data to the data reception device.

While the present invention has been described with reference to the particular embodiments and drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

100: data transmission device 110: disk reader
120: chunk data transmission unit 130: transmission period control unit
140: lost chunk control unit 150: RTT measurement unit
200: data receiving apparatus 210: chunk data receiving unit
220: disc writer 230: control information transmission unit
240: data retransmission request device 250: RTT measurement unit
260: lost chunk management unit 270: retransmission request time calculation unit

Claims (28)

Checking the first lost chunk data among the first chunk data received from the data transmission device, and generates a first retransmission request message requesting the retransmission of the identified first lost chunk data to transmit to the data transmission device Chunk management; And
A second retransmission request message, a message for requesting retransmission of second lost chunk data among second chunk data to be received from the data transmission apparatus after the first retransmission request message is transmitted, to the data transmission apparatus; And a retransmission request point calculator for dynamically calculating a retransmission request point to be transmitted in advance.
The retransmission request timing calculator is configured to retransmit the first lost chunk data when the first retransmission request message is generated, a round trip time (RTT), the number of the identified first lost chunk data, and the data transmission device. And the retransmission request time point is calculated using the transmission period at the time. delete The method of claim 1,
If the second retransmission request message transmitted at the retransmission request point is lost, the lost chunk manager retransmits the second retransmission request message at a time point when the RTT elapses from the retransmission request point. . The method of claim 1,
When a new transmission period is received from the data transmission device while the first lost chunk data are received from the data transmission device or while waiting for the retransmission request time, the retransmission request time calculation unit is configured to consider the new transmission period. A data receiving device, characterized in that the retransmission request time point is recalculated. 5. The method of claim 4,
The retransmission request timing calculator is configured to perform the retransmission using a time point when the new transmission period is received, the number of first lost chunk data re-received from the data transmission device in the transmission period, and a new transmission period received from the data transmission device. A data receiving device, characterized in that the request time is recalculated. The method of claim 5,
When the new transmission period is received, the lost chunk manager is configured to determine the number of the first lost chunk data (the first re-received from the data transmission apparatus in the transmission period from the time point when the new transmission period is received. And generating the second retransmission request message to the data transmission apparatus at a time elapsed by the number of lost chunk data) x new transmission cycle). The method of claim 1,
The lost chunk manager,
A list creation unit for creating a first lost chunk list by combining the unique numbers of the identified first lost chunk data;
A packet generator configured to generate a plurality of sublist packets by dividing the first lost chunk list into a plurality of sublists based on a maximum transmission unit (MTU);
The message type determination unit determines a message type of the plurality of sublist packets according to a position where the plurality of sublist packets belong to the first lost chunk list, and writes the determined message type in the plurality of sublist packets. ; And
And a message transmitter configured to transmit the plurality of sublist packets in which the message type is described, to the data transmission apparatus as the first retransmission request message. The method of claim 7, wherein
The message type determination unit, if the first sublist packet, one of the plurality of sublist packets, is the first packet of the first lost chunk list, determines the message type of the first sublist packet as type A, If the first sublist packet is one of the packets except for the first and the last of the first lost chunk list, the message type of the first sublist packet is determined as type B, and the first sublist packet is the first sublist packet. If the last packet of the lost chunk list, the message type of the first sublist packet is determined as type C,
And one type A and one type B, and at least one type B. 9. The method of claim 8,
And the message type determination unit further writes the largest unique number among the received first chunk data in the first sublist packet determined as the type C. 9. The method of claim 8,
The data transmission device receiving the plurality of sublist packets in which the message type is described, determines the received data among the first chunk data with reference to the message type, and in the memory used when transmitting the first chunk data. And deleting data determined to have been received. The method of claim 10,
The data transmission device receiving the first sublist packet in which the type A is described, checks the smallest unique number among the unique numbers described in the first sublist packet, and the smallest unique number among the first chunk data. Data receiving device, characterized in that for determining the smaller unique data is received. The method of claim 10,
The data transmission device receiving the first sublist packet in which the type B is described may include first lost chunk data having a unique number greater than or smaller than the unique numbers described in the first sublist packet among the first chunk data. It is determined that there is a data receiving device. The method of claim 10,
The data transmission device receiving the first sublist packet in which the type C is described is greater than the largest unique number among the first lost chunk data described in the first sublist packet and is among the received first chunk data. And data up to the largest unique number are determined to have been received. The method of claim 10,
If the size of the first lost chunk list is less than or equal to the MTU, the packet generator generates the first lost chunk list as one list packet, and the message type determiner determines the message type of the generated list packet as type D. ,
Receiving the list packet described in the type D, the data transmission device determines that all data having a unique number other than the unique numbers described in the list packet among the first chunk data are received from the type D described in the list packet. Data receiving apparatus, characterized in that. 9. The method of claim 8,
If the message type of the plurality of sublist packets includes the type A, the type B, and the type C, the packet generator may include the unique numbers listed at the end of the sublist packets having the type A and the type B, respectively. And repeating the writing of sublist packets having the B and the type C at the beginning. In the data receiving method of the data receiving apparatus,
Confirming, by the data receiving apparatus, first lost chunk data among the first chunk data received from the data transmitting apparatus;
Generating, by the data receiving device, a first retransmission request message requesting retransmission of the identified first lost chunk data to the data transmission device; And
The data receiving apparatus generates a second retransmission request message-a message for requesting retransmission of second lost chunk data among second chunk data to be received from the data transmission apparatus after the first retransmission request message is transmitted. And dynamically calculating a retransmission request time point to be transmitted to the data transmission device in advance.
In the calculating step, the data receiving apparatus, the time when the first retransmission request message is generated, RTT (Round Trip Time), the number of the identified first lost chunk data and the first loss in the data transmission apparatus And calculating the retransmission request time point using a transmission period when retransmitting chunk data. delete 17. The method of claim 16,
Retransmitting, by the data receiving apparatus, the second retransmission request message when the RTT elapses from the retransmission request time when the second retransmission request message transmitted at the retransmission request time is lost; Data receiving method, characterized in that. 17. The method of claim 16,
And recalculating, by the data receiving device, the retransmission request point in consideration of the received new transmission period when the new transmission period is received from the data transmission device. 20. The method of claim 19,
The retrieving may include: at the data receiving device, a time point when the new transmission period is received, the number of first lost chunk data re-received from the data transmission device in the transmission period, and a new transmission received from the data transmission device. And recalculating the retransmission request time using a period. 21. The method of claim 20,
When the new transmission period is received, the data receiving apparatus starts from the time point when the new transmission period is received ((the number of the first lost chunk data identified-the first loss re-received from the data transmission apparatus in the transmission period). And generating the second retransmission request message to the data transmission device at a time elapsed by the number of chunk data) x new transmission cycle). 17. The method of claim 16,
Generating and transmitting the first retransmission request message includes:
Generating, by the data receiving apparatus, a first lost chunk list by combining unique numbers of the identified first lost chunk data;
Generating, by the data receiving apparatus, the plurality of sublist packets by dividing the first lost chunk list into a plurality of sublists based on a maximum transmission unit (MTU);
Determining, by the data receiving apparatus, a message type of the plurality of sublist packets according to a position where the plurality of sublist packets belong to the first lost chunk list;
Writing, by the data receiving apparatus, the determined message type in the plurality of sublist packets; And
And transmitting, by the data receiving apparatus, the plurality of sublist packets in which the message type is described, to the data transmitting apparatus as the first retransmission request message. The method of claim 22,
The determining of the message type may include: determining, by the data receiving apparatus, if a first sublist packet, one of the plurality of sublist packets, is the first packet of the first lost chunk list. A message type is determined as type A. If the first sublist packet is one of packets except for the first and last parts of the first lost chunk list, the message type of the first sublist packet is determined as type B. And if the first sublist packet is the last packet of the first lost chunk list, determining the message type of the first sublist packet as type C. 24. The method of claim 23,
The data transmission device receiving the plurality of sublist packets in which the message type is described, determines the received data among the first chunk data with reference to the message type, and in the memory used when transmitting the first chunk data. And deleting the data determined to have been received. 25. The method of claim 24,
The data transmission device receiving the first sublist packet in which the type A is described, checks the smallest unique number among the unique numbers described in the first sublist packet, and the smallest unique number among the first chunk data. Data receiving method characterized in that the smaller unique number of the data is determined to have been received. 25. The method of claim 24,
The data transmission device receiving the first sublist packet in which the type C is described is greater than the largest unique number among the first lost chunk data described in the first sublist packet, and the received first chunk data. Data to the largest unique number of the data receiving method characterized in that it is determined that the reception is complete. 25. The method of claim 24,
And generating, by the data receiving apparatus, the first lost chunk list as one list packet when the size of the first lost chunk list is less than or equal to the MTU.
The determining of the message type may include: determining, by the data receiving apparatus, a message type of the generated list packet as type D,
The data transmission device receiving the list packet in which the type D is described, determines that all data having a unique number other than the unique numbers described in the list packet among the first chunk data are received from the type D. How to receive data. 24. The method of claim 23,
The describing may include: when the message type of the plurality of sublist packets includes the type A, type B, and type C, the data receiving apparatus, at the end of the sublist packets having the type A and the type B; And repeating the above-described unique numbers at the beginning of the sublist packets having the type B and the type C, respectively.

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