JP2005117301A - Communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve efficient retransmission by setting a proper retransmission timer value, in a communication apparatus which communicates signals. <P>SOLUTION: In the communication apparatus, a data signal transmission means transmits an object data signal to be transmitted to a communication partner, an answer signal receiving means receives an answer signal that the communication party having received the data signal transmitted by the data signal transmission means transmits, a retransmission timer value setting means sets a retransmission timer value according to the size of the object data signal to be transmitted, and a data signal retransmission means retransmits the object data signal to be transmitted by the data signal transmission means when a time corresponding to the retransmission timer value set by the retransmission timer value setting means passes while the answer signal from the communication partner is not received by the answer signal receiving means after the data signal transmission means transmits the data signal to be transmitted to the communication party. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication device that communicates data of a TCP (Transmission Control Protocol) packet using, for example, a mobile communication network, and in particular, a technique for realizing efficient retransmission by setting an appropriate retransmission timer value. About.

  For example, in TCP communication, the transmission side transmits data of a TCP packet, and when the reception side receives the data, a response signal (ACK) is transmitted to the transmission side. On the transmission side, a retransmission timer value is set when transmitting TCP packet data, and if there is no response from the reception side even if the time corresponding to the retransmission timer value (retransmission timer time) elapses, Resend data. The retransmission timer value is set based on, for example, an upper limit value and a lower limit value or a round trip time.

However, in the conventional communication apparatus, when performing TCP communication, the retransmission timer value is set regardless of the size of the data of the TCP packet to be transmitted. . Specifically, if the retransmit timer value is small and the TCP packet data size is large, re-transmission occurs easily, and if the retransmit timer value is large and the TCP packet data size is small, it is a wasteful wait for retransmission. Time will occur.
The present invention has been made in view of such a conventional situation, and provides a communication apparatus capable of realizing retransmission efficiency by setting an appropriate retransmission timer value when transmitting a data signal. For the purpose.

In order to achieve the above object, the communication apparatus according to the present invention communicates signals as follows.
That is, when the data signal transmission means transmits a data signal to be transmitted to the communication partner and the response signal is transmitted from the communication partner that has received the data signal transmitted by the data signal transmission means, the response The signal receiving means receives a response signal transmitted from the communication partner.
At this time, the retransmission timer value setting means sets the retransmission timer value based on the size of the data signal to be transmitted. Then, after the data signal retransmitting means transmits the data signal to be transmitted to the communication partner by the data signal transmitting means, the response signal from the communication partner is not received by the response signal receiving means (that is, received) If the time corresponding to the retransmission timer value set by the retransmission timer value setting means has elapsed, the data signal to be transmitted is transmitted again (that is, retransmitted) by the data signal transmission means.
Therefore, since the retransmission timer value is set based on the size of the data signal to be transmitted, it is possible to set the appropriate retransmission timer value and realize the efficiency of retransmission.

Here, various signals may be used as signals to be communicated, data signals to be transmitted, and response signals, respectively.
Moreover, as communication, wireless communication may be used and wired communication may be used.
Various communication devices may be used as communication partners.
As the size of the data signal to be transmitted, for example, the amount of data included in the data signal can be used, and the amount of bits or the amount of bytes can be used.
Various modes may be used for setting the retransmission timer value based on the size of the data signal to be transmitted.
Various times may be used as the time corresponding to the retransmission timer value. For example, the time corresponding to the value of the retransmission timer value (for example, [second]) or the value of the retransmission timer value is predetermined. A time (for example, [second] or the like) that coincides with the result of multiplication or addition of values can be used.

Below, the structural example which concerns on this invention is shown further.
As one configuration example, if the other conditions are the same, for example, the retransmission timer value setting means sets a large retransmission timer value when the size of the data signal to be transmitted is large, and the data signal to be transmitted When the size of is small, a small retransmission timer value is set.
As one configuration example, a lower limit value and an upper limit value are provided for the retransmission timer value. Then, the retransmission timer value setting means sets, as a retransmission timer value, a value that is a value that is greater than or equal to the lower limit value for the retransmission timer value or that exceeds the lower limit value and that is less than or equal to the upper limit value for the retransmission timer value. To do.
As one configuration example, the correspondence between the size of the data signal to be transmitted and the retransmission timer value, the correspondence between the size of the data signal to be transmitted and the upper limit of the retransmission timer value, and the size of the data signal to be transmitted And the correspondence between the retransmission timer value and the lower limit value. Then, the retransmission timer value setting means sets a retransmission timer value based on one or more of these correspondences.

As one configuration example, the retransmission timer value setting means retransmits a value obtained by adding an adjustment value (adjustment value of retransmission timer value) according to the size of a data signal to be transmitted to a reference value (reference value of retransmission timer value). Set as timer value. As an example of the configuration, if the other conditions are the same, for example, the retransmission timer value setting means uses a large adjustment value when the size of the data signal to be transmitted is large, and When the size is small, a small adjustment value is used. Here, for example, the reference value is set to a value unrelated to the size of the data signal. As one configuration example, the correspondence between the size of the data signal to be transmitted and the adjustment value is stored. Then, the retransmission timer value setting means sets the adjustment value based on the correspondence.
As one configuration example, the retransmission timer value setting means sets the retransmission timer value based on the size of the data signal to be transmitted and the round trip time. As one configuration example, the retransmission timer value setting means increases and sets the retransmission timer value as the number of retransmissions increases for the same transmission target data signal. Note that the retransmission timer value may be set based on various values.

As one configuration example, the communication partner is a server or the like.
As one configuration example, the data signal to be transmitted is a received data signal. That is, the communication device is a relay device that transmits a received data signal to a communication partner.
As one configuration example, a wireless communication network is used for communication between a communication device and a communication partner.
As one configuration example, a mobile communication network is used for communication between a communication device and a communication partner. That is, the data signal transmitted from the communication device is transmitted to the communication partner device via the mobile communication network. Various mobile communication systems may be used. For example, a mobile phone system, a simple mobile phone system (PHS: Personal Handy phone System), or the like can be used.
As one configuration example, wireless communication is used as communication. As one configuration example, the communication device is a wireless communication device.
As one configuration example, retransmission processing of TCP communication is used. As one configuration example, a data signal of a TCP packet is used as a data signal. As one configuration example, TCP / IP (Internet Protocol) communication is used.

  As described above, according to the communication device of the present invention, when transmitting a data signal to be transmitted to a communication partner and receiving a response signal transmitted from the communication partner, the data signal to be transmitted The retransmission timer value is set based on the size of the transmission, and after the data signal to be transmitted is transmitted to the communication partner, the set retransmission timer is set in a state where no response signal is received from the communication partner. When the time corresponding to the value has elapsed, the data signal to be transmitted is transmitted again. For example, even when data signals of various sizes are transmitted, each data signal is appropriate. By setting a proper retransmission timer value, the efficiency of retransmission can be realized.

Embodiments according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of the hardware configuration of the communication apparatus according to the present embodiment.
The communication apparatus of this example stores the setting information such as the antenna 1, the wireless unit 2 that transmits and receives wireless signals using the antenna 1, the operation unit 3 that inputs data, and the control program, communication, and the like in a database or the like. Storage unit 4, display unit 5 for displaying communication status and setting status, IC card 6 for storing mobile communication telephone numbers, and data input for inputting / outputting data for TCP / IP communication An output interface (data input / output I / F) 7 and a control unit 8 that controls signal processing associated with communication and TCP / IP communication and display are configured. The mobile communication telephone number can be stored in the storage unit 4 instead of the IC card 6, for example.

A communication apparatus according to the first embodiment of the present invention will be described.
In the communication apparatus of this example, the storage unit 4 stores a table that associates the data size (data size) with the lower limit value of the retransmission timer value (retransmission timer lower limit value).
FIG. 2 shows an example of such a correspondence table. In this example, a data size of “1 to 100 bytes” or “100 to 200 bytes” is associated with a retransmission timer lower limit value of “1 sec (seconds)”, and “1300 to 1400 bytes” or “1400 to 1400”. A data size of “1500 bytes” or “1500 bytes or more” is associated with a retransmission timer lower limit value of “5 sec”. Further, in this example, when the data size is 1500 bytes or more, the data size is divided by 1500 bytes.

FIG. 3 shows an example of a procedure for changing the TCP retransmission timer value by the communication apparatus of this example. In this example, in order to change the retransmission timer value, the lower limit value of the retransmission timer value is changed.
The communication apparatus of this example can transmit and receive TCP / IP data using the mobile communication network, and waits for data for TCP / IP communication to be received at the data input / output I / F 7 (steps). S1) Waits for data reception until data for TCP / IP communication is received.
Here, when receiving data for TCP / IP communication (step S2), the communication device checks the size of the received data (step S3). In addition, a correspondence table of the data size and the corresponding retransmission timer lower limit value is recorded in the storage unit 4 of the communication apparatus. The communication device refers to the retransmission timer lower limit value corresponding to the size of the received data from the table (step S4), and changes the lower limit value of the retransmission timer value to the reference value from the table (step S5). Thereby, when the size of the received data is large, the retransmission timer value can be set large, and when the size of the received data is small, the retransmission timer value can be set small.

  In the communication apparatus, the TCP retransmission timer value is calculated and set based on the lower limit value, the upper limit value, and the round trip time (step S6). The communication device transmits data in a TCP / IP packet and starts a retransmission timer (step S7). After transmitting data, the communication apparatus waits for a data response (ACK) from a server or the like as a transmission partner (step S8), and receives a data response before the retransmission timer expires (step S9). The process returns to waiting for data for TCP / IP communication without retransmitting the data (step S1). On the other hand, if the retransmission timer times out before receiving the data response (step S10), the communication device calculates the retransmission timer value based on the lower limit value, upper limit value, and round trip time of the TCP retransmission timer. Then, after setting (step S6), data transmission (retransmission), a retransmission timer is started (step S7), and a response is waited (steps S8 to S10).

  Here, when a mobile communication network is used for TCP packet data communication, even if the maximum value of the line speed of the mobile communication network is 9600 bps, the actual line speed depends on the radio wave condition. Will be slower. For example, if the effective value of the line speed is about 4800 bps and the size of the TCP / IP packet to be transmitted is 1500 bytes, it takes about 2.5 seconds for the TCP / IP packet to reach the server or the like. Since the data response has a small size, the time required for data to reach the communication device from the server or the like is less than 0.1 seconds. Then, it takes at least about 2.5 seconds from sending a TCP / IP packet to receiving a response. In such a case, if a value of 2.5 seconds or more is set as the lower limit value of the retransmission timer value in the table, a response can be received before the retransmission timer times out.

FIG. 4 shows a process of performing TCP / IP communication to a server or the like (herein referred to as a server 12 or the like) via a mobile communication network by the communication device of this example (herein referred to as the communication device 11). An example of the flow is shown.
When the communication device 11 transmits data of a TCP / IP packet (process 1), the server 12 or the like receives the data (process 2), and the server 12 or the like transmits a response (ACK) (process 3), the communication The device 11 receives the response (process 4). In this case, for example, when small size data (for example, 10 bytes) is transmitted as a TCP / IP packet (processing 1), the table is referred to as a retransmission timer value and a small value (for example, the retransmission timer value is 2 seconds). When the retransmission timer lower limit value is 1 second, a value of 2 seconds) is set (Process 5), but the time required for data transmission is also short, so the data response takes about 1 second within the time of the retransmission timer value, for example. Can be received (process 4).

Further, communication similar to the above is performed (Process 6), (Process 7), (Process 8), and (Process 9). In this case, for example, when transmitting a large size data (for example, 1500 bytes) as a TCP / IP packet (process 6), referring to the table as a retransmission timer value, for example, the retransmission timer value is 2 seconds. When the retransmission timer lower limit value is 5 seconds, a value of 5 seconds) is set (process 10), so that a data response can be received, for example, in about 4 seconds within the time of the retransmission timer value (process 9). ).
Further, communication similar to the above is performed (Process 11), (Process 12), (Process 13), and (Process 14). In this case, for example, when small size data (for example, 10 bytes) is transmitted in a TCP / IP packet (process 11), the table is referred to as a retransmission timer value and a small value (for example, the retransmission timer value is 2 seconds). When the retransmission timer lower limit is 1 second, a value of 2 seconds) is set (process 15), so that a data response can be received within approximately 1 second within the time of the retransmission timer value (process 14). ), Even if the data has not arrived, it can be resent immediately.

As described above, the communication apparatus of this example has a function of performing TCP / IP communication using the mobile communication network, and the TCP retransmission timer value is automatically changed according to the data size of the TCP data to be transmitted. By doing so, wasteful retransmission of TCP data can be reduced, and efficiency can be improved.
Therefore, in the communication apparatus of this example, the automatic change function of the TCP retransmission timer value is used, for example, even when handling both small data and large data, wasteful retransmission does not occur. Charges can be prevented or reduced, and wasted time for retransmission can be eliminated or reduced.
In the communication device of this example, the control unit 8 receives the data stored in the IC card 6 and the data input / output I / F 7 using the wireless unit 2 and the antenna 1 to the communication partner server. The data signal transmission means is configured by the function of wirelessly transmitting a TCP / IP data signal to be transmitted. In the communication apparatus of this example, the control unit 8 uses the antenna 1 and the radio unit 2 to receive a response signal (ACK) transmitted from a server or the like as a communication partner via a radio line. Response signal receiving means is configured. In the communication apparatus of this example, a retransmission timer value setting unit is configured by the function in which the control unit 8 sets the retransmission timer value based on the size of the data signal and the stored contents of the storage unit 4. Further, in the communication apparatus of this example, when there is no response to the transmitted data signal when the retransmission timer time has elapsed, the control unit 8 uses the stored contents of the IC card 6, the radio unit 2 and the antenna 1 to A data signal retransmission means is configured by the function of retransmitting the data signal.

A communication apparatus according to the second embodiment of the present invention will be described.
FIG. 5 shows an example of a procedure for changing the TCP retransmission timer value by the communication apparatus of this example. In this example, in order to change the retransmission timer value, a predetermined value corresponding to the data is added to the retransmission timer value.
The communication apparatus of this example can transmit and receive TCP / IP data using a mobile communication network, and waits for data for TCP / IP communication to be received at the data input / output I / F 7 (step S11). ) And waits for data reception until data for TCP / IP communication is received.
Here, when receiving data for TCP / IP communication (step S12), the communication apparatus checks the size of the received data (step S13). Further, the communication device calculates a retransmission timer addition value X at a constant rate based on the size of the received data (step S14). Specifically, in this example, as the retransmission timer addition value X, X = [{[data size] / ([maximum communication speed] × [actual efficiency])} × [addition rate]] is calculated. The addition rate is for adjusting according to the mobile communication network or device using the retransmission timer addition value X. The retransmission timer addition value X may be obtained with reference to a table. The retransmission timer addition value X is set to a large value if the data is large, and to a small value if the data is small.

The communication apparatus calculates a retransmission timer value based on the round trip time (step S15), and adds the retransmission timer addition value X to the calculated retransmission timer value (step S16). In the communication apparatus, the retransmission timer value (the addition result) calculated in this way is set (set) within the range between the lower limit value and the upper limit value (step S17). Then, the communication device transmits data in a TCP / IP packet and starts a retransmission timer (step S18). After the data transmission, the communication apparatus waits for a data response (ACK) from a server or the like as a communication partner (step S19), and receives a data response before the retransmission timer expires (step S20). ), The process returns to waiting for data for TCP / IP communication without retransmitting the data (step S11). On the other hand, in the communication apparatus, when the retransmission timer expires before receiving the data response (step S21), the retransmission timer value is calculated and set by checking the data size or the like (steps S13 to S13). In step S17), after data transmission (retransmission), a retransmission timer is started (step S18), and a response is waited (steps S19 to S21).
Thus, in this example, the retransmission timer value is shortened when small data is transmitted, and the retransmission timer value is lengthened when large data is transmitted. For this reason, for example, even when both small data and large data are handled, it is possible to prevent useless re-transmissions due to unnecessary re-transmissions and useless time before re-transmission. Or it is reduced.

FIG. 6 shows a process of performing TCP / IP communication to a server or the like (herein referred to as a server 22 or the like) via a mobile communication network by the communication device of this example (here called the communication device 21). An example of the flow is shown.
When the communication device 21 transmits data of a TCP / IP packet (process 1), the server or the like 22 receives the data (process 2), and the server or the like 22 transmits a response (ACK) (process 3), the communication The device 21 receives the response (process 4). In this case, for example, when small-size data (for example, 10 bytes) is transmitted as a TCP / IP packet (Process 1), a small value (refer to the arithmetic expression or table of the retransmission timer addition value X as the retransmission timer value) For example, when the retransmission timer value is 2 seconds and the retransmission timer addition value is 0.1 seconds, a value of 2.1 seconds is set (Process 5), but the time required for data transmission is also short. For example, the data response can be received within about 1 second within the time of the timer value (process 4).

Further, communication similar to the above is performed (Process 6), (Process 7), (Process 8), and (Process 9). In this case, for example, when large-size data (for example, 1500 bytes) is transmitted as a TCP / IP packet (process 6), a large value (refer to the calculation formula or table of the retransmission timer addition value X as the retransmission timer value) For example, when the retransmission timer value is 2 seconds and the retransmission timer addition value is 3 seconds, a value of 5 seconds) is set (process 10). Can be received (process 9).
Further, communication similar to the above is performed (Process 11), (Process 12), (Process 13), and (Process 14). In this case, for example, when small-size data (for example, 10 bytes) is transmitted as a TCP / IP packet (process 11), a small value (refer to the arithmetic expression or table of the retransmission timer addition value X as the retransmission timer value) For example, when the retransmission timer value is 2 seconds and the retransmission timer addition value is 0.1 seconds, a value of 2.1 seconds) is set (process 15). For example, about 1 within the time of the retransmission timer value. A data response can be received in seconds (process 14), and even if data does not arrive, it can be retransmitted immediately.

As described above, the communication apparatus of this example has a function of performing TCP / IP communication using the mobile communication network, and the TCP retransmission timer value is automatically changed according to the data size of the TCP data to be transmitted. By doing so, wasteful retransmission of TCP data can be reduced, and efficiency can be improved.
In the communication apparatus of this example, a retransmission timer value setting unit is configured by the function in which the control unit 8 sets the retransmission timer value based on the size of the data signal. In the communication apparatus of this example, the retransmission timer value adjustment value (retransmission timer addition value X) is calculated based on the size of the data signal, and the retransmission timer value reference value (retransmission timer addition value based on the round trip time). (Retransmission timer value to which X is added) is calculated, and further set so that the retransmission timer value falls within the range between the upper limit value and the lower limit value of the retransmission timer value.

The background of the technology related to the present invention will be described below. Note that the matters described here are not necessarily limited to the conventional technology.
For example, in TCP, when a TCP packet including data is transmitted, the other party receiving the packet transmits ACK (positive response signal). The side that has transmitted the TCP packet including the data can confirm that the transmitted data has arrived at the partner by ACK from the partner. On the other hand, if the ACK from the partner does not arrive, the TCP packet including the data is retransmitted. Retransmission is performed when a retransmission timer is set when a TCP packet including data is transmitted, and ACK is not received before the retransmission timer times out. This retransmission timer is calculated based on a round trip time, which is a time from when a TCP packet including data is transmitted until ACK is returned. If no ACK is received even after retransmission, the retransmission timer is increased at a constant rate. In addition, a lower limit value and an upper limit value are set for the retransmission timer and fluctuate within the range.

FIG. 7 shows an example of a TCP communication sequence using a mobile communication network. Data is transmitted from the communication device 31 to the server 32, and a response (ACK) is returned from the server 32 to the communication device 31. The communication device 31 and the server 32 are connected via a mobile communication network.
For example, when the communication device 31 transmits data of a TCP / IP packet (1), the server 32 receives the data (2), and the server 32 transmits a response (ACK) (3), the communication device 31 The response is received.
The communication device 31 sets (sets) the value of the retransmission timer (5) at the time of the above-described data transmission (5), and thereafter, if no data response is received within the retransmission timer time, Is retransmitted (6). When the server 32 receives the retransmission data (7) and the server 32 transmits a response (ACK) (8), the communication device 31 receives the response (9). In the communication device 31, the value of the retransmission timer is also set during retransmission (10).

Here, as the retransmission timer value, when data transmission occurs, a value recalculated in consideration of the round trip time is set. For the retransmission timer value, a lower limit value and an upper limit value can be set, and fluctuate within the range (that is, within a range between the lower limit value and the upper limit value). However, since the retransmission timer value fluctuates in consideration of the round trip time in TCP, conventionally, the lower limit value and the upper limit value of the retransmission timer value are set as initial fixed values and should be changed during communication. There was no.
Unlike TCP / IP communication using a wired LAN (Local Area Network), communication speed is very low when TCP / IP communication is performed using a mobile communication network. Also, depending on the state of the radio wave, retransmission of the wireless section data due to missing of the wireless section data occurs, and the effective communication speed often becomes slower than the communication speed defined by the mobile communication network.
As an example, while transmitting data of a TCP packet having a small size, the round trip time is short, and a small value is set as the retransmission timer value. At this time, if data of a large TCP packet is transmitted, the response speed is returned after the data is transmitted because the effective communication speed may be slower than the specified communication speed in addition to the very low communication speed. It takes time to complete. However, since a small value is set as the retransmission timer value, the retransmission timer time elapses before a response is returned, and data retransmission occurs.

When such data retransmission occurs, for example, when the mobile communication network employs packet charging, there is a problem that unnecessary charging is generated for packets corresponding to retransmission data. In addition, there is a problem that unnecessary communication time corresponding to the time required for retransmission occurs.
On the other hand, in order to eliminate such unnecessary billing and communication time due to packets for retransmission data, a method can be considered in which the lower limit of the retransmission timer value is set to a large value in advance in consideration of the round trip time of large data. . However, if the lower limit value of the retransmission timer value is set to a large value, even when retransmission occurs when small data is transmitted, the retransmission timer value is large, so that a wasteful retransmission waiting time occurs. was there.
Therefore, the present invention provides a technique that can solve such problems.

Here, the configuration of the communication apparatus according to the present invention is not necessarily limited to the above-described configuration, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various devices and systems.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
In addition, various processes performed in the communication apparatus according to the present invention are controlled by executing a control program stored in a ROM (Read Only Memory) by a processor using, for example, a hardware resource including a processor and a memory. For example, each functional unit for executing the processing may be configured as an independent hardware circuit.
Further, the present invention can also be grasped as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the above control program, or the program (itself). The processing according to the present invention can be performed by inputting a program from the recording medium to a computer and causing the processor to execute the program.

It is a figure which shows the structural example of the communication apparatus which concerns on the Example of this invention. It is a figure which shows an example of the correspondence table of data size and a retransmission timer lower limit. FIG. 6 is a diagram showing an example of a procedure for changing a retransmission timer value according to the first embodiment of the present invention. FIG. 6 is a diagram showing an example of a flow of a retransmission timer value change process according to the first embodiment of the present invention. It is a figure which shows an example of the procedure of the change process of the retransmission timer value which concerns on 2nd Example of this invention. It is a figure which shows an example of the flow of the change process of the retransmission timer value which concerns on 2nd Example of this invention. It is a figure which shows an example of the TCP / IP communication sequence via a mobile communication network.

Explanation of symbols

  1 ・ ・ Antenna, 2 ・ ・ Wireless unit 3 ・ ・ Operation unit 4 ・ ・ Storage unit 5 ・ ・ Display unit 6 ・ ・ IC card 7 ・ ・ Data input / output I / F 8 ・ ・ Control unit 11, 21, 31 ..communication device, 12, 22, 32 .. server,

Claims (1)

In a communication device that communicates signals,
Data signal transmitting means for transmitting a data signal to be transmitted to a communication partner;
A response signal receiving means for receiving a response signal transmitted from a communication partner receiving the data signal transmitted by the data signal transmitting means;
Retransmission timer value setting means for setting a retransmission timer value based on the size of the data signal to be transmitted;
After the data signal to be transmitted is transmitted to the communication partner by the data signal transmitting means, the response timer is set by the retransmission timer value setting means in a state where the response signal from the communication partner is not received by the response signal receiving means. When the time corresponding to the retransmission timer value has elapsed, the data signal retransmission means for retransmitting the data signal to be transmitted by the data signal transmission means,
A communication apparatus comprising:

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