JP2010245943A - Communication device, method of dividing packet, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the usage rate of a band of a specific logical data link from being fixed in a state of being lower than that of a band of the other logical data link, in communication using a multilink PPP. <P>SOLUTION: In this communication device which is connected to a communication line, divides a packet transmitted from the transmission side of the packet, and transmits each of the divided packets to the reception side of the packet using each of a plurality of logical data links set in the communication line, first data obtained by adding a header required for communication via the communication line to the packet transmitted from the transmission side of the packet are generated, the division number for dividing the packet is calculated based on the length of the packet and an MRU being the maximum length of the data that can be received by the reception side of the packet at a time, and the first data are divided by being divided by the division number. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication apparatus, a packet division method, and a program for dividing a packet transmitted from a packet transmission side and transmitting the divided packet to a packet reception side.

  In communication using multilink PPP (Point to Point Protocol), when dividing a packet by MRU (Maximum Receive Unit), the packet is divided into m multilink PPP packets according to the length of the packet and the MRU. Divided. The MRU is the maximum data length that can be received at one time by the packet receiver. In this case, the breakdown of the divided m multilink PPP packets is (m−1) multilink PPP packets having the same data length as the MRU and one multilink PPP packet having a data length shorter than the MRU. It becomes.

  Here, PPP is a WAN (Wide Area Network) protocol used in communication for connecting two points. Multilink PPP is a protocol that allows a plurality of PPP connections to be established simultaneously using a plurality of logical data links.

  Consider a case in which a plurality of logical data links are used in a round robin method in communication using multilink PPP, and packets having a constant length such as a video stream are continuously transmitted. In this case, if there is a common divisor between the number of divided packets and the number of logical data links, the logical data link that transmits a multilink PPP packet having a data length shorter than that of the MRU is fixed. That is, there is a problem that the usage rate of the bandwidth of a specific logical data link is fixed in a state lower than the usage rate of the bandwidth of another logical data link.

  In such a situation, when the number of logical data links to be used is dynamically increased / decreased according to the usage rate of the logical data link bandwidth, this logical data is set as a reference threshold for increasing the number of logical data links. In some cases, the link bandwidth usage rate does not reach and the number of logical data links cannot be increased.

  By the way, techniques for dividing a packet according to the length of the packet are disclosed in, for example, Patent Document 1 and Patent Document 2. The technique disclosed in Patent Document 1 is a technique in which, in packet communication having a multilayer protocol structure, a packet is divided into a length that does not cause an error according to the type of protocol and transmitted.

  The technique disclosed in Patent Document 2 is a technique in which packets are divided and transmitted so that no IP fragment is generated in an intermediate node or the like of a communication path in packet communication using PPP. Note that the IP fragment means that a node divides an IP packet according to the maximum frame length of a protocol lower than IP.

JP 2004-289431 A JP 2006-157544 A

  The techniques disclosed in Patent Document 1 and Patent Document 2 described above assume that divided packets are transmitted simultaneously using a plurality of logical data links, as in communication using multilink PPP. Absent.

  Therefore, even if the techniques disclosed in Patent Document 1 and Patent Document 2 are used, the usage rate of a specific logical data link bandwidth is fixed in a state lower than the usage rates of other logical data link bandwidths. The problem is not solved.

  The present invention is a communication that can avoid a situation in which the bandwidth usage rate of a specific logical data link is fixed lower than the bandwidth usage rates of other logical data links in communications using multilink PPP. An object is to provide an apparatus, a packet division method, and a program.

In order to achieve the above object, the present invention provides:
A packet that is connected to a communication line and that is transmitted from a packet transmission side is divided, and each of the divided packets is received by using each of a plurality of logical data links set in the communication line. A communication device for transmitting to
The first data in which a header required for communication via the communication line is added to the packet transmitted from the packet transmission side is generated, and the length of the packet and the reception side of the packet can be received at a time Based on the MRU which is the maximum data length, the number of divisions for dividing the packet is calculated, and the first data is divided by the number of divisions.

Further, the packet transmitted from the packet transmission side connected to the communication line is divided, and each of the divided packets using each of the plurality of logical data links set in the communication line is changed to the packet. A packet division method in a communication device that transmits to a receiving side,
Processing for generating first data in which a header necessary for communication via the communication line is added to the packet transmitted from the packet transmission side;
A calculation process for calculating the number of divisions for dividing the packet based on the length of the packet and the MRU which is the maximum data length that can be received at one time by the receiving side of the packet;
Dividing the first data by dividing the first data by the number of divisions.

Further, the packet transmitted from the transmission side of the packet is connected to the communication line, and each of the divided packets using each of the plurality of logical data links set in the communication line is divided into the packets. To the communication device that transmits to the receiving side,
A function of generating first data in which a header necessary for communication via the communication line is added to the packet transmitted from the packet transmission side;
A calculation function for calculating the number of divisions for dividing the packet based on the length of the packet and the MRU which is the maximum data length that can be received at one time by the receiving side of the packet;
And a division function for dividing the first data by dividing the first data by the number of divisions.

  According to the present invention, the communication device is connected to a communication line in which a plurality of logical data links are set, and a first packet in which a header necessary for communication via the communication line is added to a packet transmitted from the packet transmission side. Generate data for Further, the communication apparatus calculates the number of divisions for dividing the packet based on the length of the packet and the MRU that is the maximum data length that can be received at one time by the packet receiving side. Is divided by the number of divisions. Then, the communication device transmits each of the first data divided using each of the plurality of logical data links to the packet receiving side.

  Therefore, it can be avoided that the usage rate of the bandwidth of a specific logical data link is fixed in a state where it is lower than the usage rate of the bandwidth of another logical data link.

It is a block diagram which shows the structure of one Embodiment of the communication system to which the communication apparatus of this invention is applied. It is a block diagram which shows an example of a structure of the communication apparatus shown in FIG. 3 is a flowchart for explaining an operation in which the communication apparatus shown in FIGS. 1 and 2 calculates a division unit length. 3 is a flowchart for explaining an operation in which the communication device shown in FIGS. 1 and 2 divides and transmits MP data according to a division unit length. FIG. 3 is a diagram showing step by step until a multilink PPP packet is generated from an IP packet received by the communication apparatus shown in FIGS. 1 and 2, wherein (a) is a case where MP data is divided by a maximum MP payload length; FIG. 7B is a diagram illustrating a case where MP data is divided by a division unit length. FIG. 3 is a diagram showing an example of the length of a multilink PPP packet transmitted using each of the logical data links set in the communication line shown in FIG. 1 and FIG. The figure which shows the case where it divides | segments by payload length, (b) is a figure which shows the case where MP data is divided | segmented by division | segmentation unit length.

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

  FIG. 1 is a block diagram showing a configuration of an embodiment of a communication system to which a communication apparatus of the present invention is applied.

  As shown in FIG. 1, the communication system according to the present embodiment includes communication devices 1-1 and 1-2, a communication terminal 3-1 connected to the communication device 1-1 by a communication line 4, and a communication device 1-2. And a communication terminal 3-2 connected by a communication line 5.

  Further, the communication device 1-1 and the communication device 1-2 are connected by the communication line 2 and use the multilink PPP using the logical data links 2-1 to 2-n set in the communication line 2. Communication. As the communication line 2, for example, PRI (Primary Rate Interface) of ISDN (Integrated Services Digital Network) can be considered. In this case, the logical data links 2-1 to 2-n are, for example, 23 B channels. . The B channel is a logical channel for ISDN data and is used for transmission of voice and data. The bandwidth of one B channel is 64 kbps.

  The communication terminals 3-1 and 3-2 are terminals on the IP packet transmitting side or receiving side. In the present embodiment, the communication terminals 3-1 and 3-2 are described as transmitting and receiving IP packets corresponding to IP (Internet Protocol) as an example, but the communication terminals 3-1 and 3-2 transmit and receive. Packets to be performed are not limited to IP packets.

  The communication devices 1-1 and 1-2 receive IP packets transmitted from the communication terminals 3-1 and 3-2. And in order to perform communication using multilink PPP, it has the function to encapsulate by adding a header to the received IP packet.

  FIG. 2 is a block diagram illustrating an example of the configuration of the communication device 1-1 illustrated in FIG. The communication device 1-2 has the same configuration.

  As shown in FIG. 2, the communication apparatus 1-1 shown in FIG. 1 includes a division number calculation unit 11, a division unit length calculation unit 12, a data division unit 13, an encapsulation unit 14, and communication IFs 15-1 to 15-1. 15-n.

  The communication IFs 15-1 to 15-n connect the communication device 1-1 and the communication lines 2 and 4. In the present embodiment, the communication line 4 is connected to the communication apparatus 1-1 via the communication IF 15-1, and the communication line 2 is connected to the communication apparatus 1-1 via the communication IF 15-2. .

  The encapsulation unit 14 receives the IP packet transmitted from the communication terminal 3-1 via the communication IF 15-1. Then, MP data that is first data in which a PPP header is added to the received IP packet is generated. By adding the PPP header to the IP packet in this way, the IP packet can be transmitted / received via the communication line 2. Then, the encapsulation unit 14 calculates the MP data length which is the length of the generated MP data and is the first data length, and outputs the calculated MP data length to the division number calculation unit 11. In addition, the encapsulation unit 14 outputs the generated MP data to the data dividing unit 13. When the encapsulation unit 14 receives the divided MP data output from the data division unit 13, the encapsulation unit 14 adds a multilink PPP header and an MP header to each of the received divided MP data. Generate a packet. Then, each of the generated multilink PPP packets is output to any of the logical data links 2-1 to 2-n via the communication IF 15-2 in a round robin manner. The MP header is a header including information necessary for reassembling the MP data transmitted after being divided into the logical data links 2-1 to 2-n. In addition, the multilink PPP header is a header necessary for transmitting and receiving IP packets via the communication line 2 in the same manner as the PPP header.

  The division number calculation unit 11 receives the MP data length output from the encapsulation unit 14. Then, the division number for dividing the MP data is calculated according to the received MP data length and the MRU. Specifically, the division number calculation unit 11 first calculates the maximum MP payload length that is the second data length by subtracting the MP header length that is the length of the MP header from the MRU. Next, the MP data length is divided by the calculated maximum MP payload length. A value obtained by rounding up the result of the division is defined as the division number. Then, the division number calculation unit 11 outputs the calculated division number and the MP data length to the division unit length calculation unit 12.

  The division unit length calculation unit 12 receives the division number and the MP data length output from the division number calculation unit 11. Then, the received MP data length is divided by the number of divisions. A value obtained by rounding up the result of the division is defined as a division unit length. Then, the division unit length calculation unit 12 outputs the calculated division unit length to the data division unit 13. The division unit length is a unit of length for dividing the MP data.

  The data division unit 13 receives the MP data output from the encapsulation unit 14 and the division unit length output from the division unit length calculation unit 12. Then, the MP data length of the received MP data is compared with the division unit length. As a result of the comparison, if the MP data length is longer than the division unit length, the MP data is divided by the division unit length from the beginning, and the divided division unit length MP data is output to the encapsulation unit 14. The data dividing unit 13 sets the length obtained by subtracting the division unit length from the MP data length of the received MP data as the MP data length, and further compares the MP data length with the division unit length. The data division unit 13 compares the MP data length with the division unit length and outputs the MP data having the division unit length to the encapsulation unit 14 until the MP data length becomes equal to or less than the division unit length. Finally, MP data having a length equal to or shorter than the division unit length is output to the encapsulation unit 14.

  Hereinafter, an operation of dividing and transmitting an IP packet in the communication system configured as described above will be described. Here, it is assumed that an IP packet having a length of 400 bytes is continuously transmitted from the communication terminal 3-1 to the communication terminal 3-2. Here, as an example, the length of each header is as shown in the following (1) to (4).

(1) MRU: 200 bytes
(2) PPP header added to IP packet: 1 byte
(3) Multilink PPP header added to the divided MP data: 4 bytes
(4) MP header added to divided MP data: 4 bytes
First, an operation in which the communication device 1-1 illustrated in FIGS. 1 and 2 calculates the division unit length will be described.

  FIG. 3 is a flowchart for explaining an operation in which the communication device 1-1 shown in FIGS. 1 and 2 calculates the division unit length.

  First, the communication terminal 3-1 transmits an IP packet toward the communication terminal 3-2.

  Upon receiving the IP packet transmitted from the communication terminal 3-1 via the communication line 4 and the communication IF 15-1, the encapsulation unit 14 of the communication device 1-1 receives the MP data obtained by adding the PPP header to the received IP packet. Generate. Then, the MP data length of the generated MP data is calculated (step S1). Here, since the length of the received IP packet is 400 bytes and the length of the PPP header added to the IP packet is 1 byte, the MP data length is 401 bytes.

  Then, the encapsulating unit 14 outputs the calculated MP data length to the division number calculating unit 11 and outputs the generated MP data to the data dividing unit 13.

  The division number calculation unit 11 that has received the MP data length output from the encapsulation unit 14 calculates a maximum MP payload length that is a length obtained by subtracting the MP header length from the MRU (step S2). Here, since the MRU is 200 bytes and the MP header length is 4 bytes, the maximum MP payload length is 196 bytes.

  Next, the division number calculation unit 11 divides the received MP data length by the maximum MP payload length calculated in step S2. Then, a value obtained by rounding up the result of the division is set as the division number (step S3). Here, since the MP data length is 401 bytes and the maximum MP payload length is 196 bytes, the number of divisions is 3.

  Then, the division number calculation unit 11 outputs the calculated division number and the MP data length to the division unit length calculation unit 12.

  The division unit length calculation unit 12 that receives the division number and the MP data length output from the division number calculation unit 11 divides the received MP data length by the division number. A value obtained by rounding up the result of the division is set as a division unit length (step S4). Here, since the MP data length is 401 bytes and the number of divisions is 3, the division unit length is 134 bytes.

  Then, the division unit length calculation unit 12 outputs the calculated division unit length to the data division unit 13.

  The above is the operation in which the communication apparatus 1-1 illustrated in FIG. 1 calculates the division unit length.

  Next, an operation in which the communication apparatus 1-1 illustrated in FIGS. 1 and 2 divides and transmits MP data according to the division unit length will be described.

  FIG. 4 is a flowchart for explaining an operation in which the communication apparatus 1-1 shown in FIGS. 1 and 2 divides and transmits MP data according to the division unit length.

  The data division unit 13 that has received the MP data output from the encapsulation unit 14 and the division unit length output from the division unit length calculation unit 12 compares the MP data length of the received MP data with the division unit length. (Step S21).

  As a result of the comparison in step S21, when the MP data length is longer than the division unit length, the MP data is divided by the division unit length from the top. Then, the divided unit length MP data is output to the encapsulation unit 14. Here, since the MP data length is 401 bytes and the division unit length is 134 bytes, the MP data length is longer than the division unit length. Therefore, a portion corresponding to 134 bytes from the beginning of the MP data is output to the encapsulation unit 14. A case where the MP data length is equal to or smaller than the division unit length as a result of the comparison in step S21 will be described later.

  Upon receiving the division unit length MP data, the encapsulation unit 14 generates a multilink PPP packet in which the multilink PPP header and the MP header are added to the received division unit length MP data (step S22). Here, a 142-byte multilink PPP packet in which a 4-byte multilink PPP header and a 4-byte MP header are added to the division unit length 134 bytes is generated.

  Then, the encapsulation unit 14 transmits the generated multilink PPP packet to the communication device 1-2 using the logical data link 2-1 (step S23).

  Next, the data division unit 13 subtracts the division unit length from the received MP data length, and sets the subtracted length as the MP data length (step S24). Here, since the received MP data length is 401 bytes and the division unit length is 134 bytes, the MP data length is 267 bytes.

  Then, the process proceeds to the operation of step S21, and the data dividing unit 13 compares the MP data length with the division unit length. Here, since the MP data length is 267 bytes and the division unit length is 134 bytes, the MP data length is longer than the division unit length. Therefore, a portion corresponding to 134 bytes from the beginning of the MP data is output to the encapsulation unit 14.

  Next, the operation proceeds to the operation of step S22, and the encapsulation unit 14 generates a multilink PPP packet in which the multilink PPP header and the MP header are added to the received MP data having the division unit length. Here, a 142-byte multilink PPP packet in which a 4-byte multilink PPP header and a 4-byte MP header are added to the division unit length 134 bytes is generated.

  Next, the operation transits to the operation of Step S23, and the encapsulation unit 14 transmits the generated multilink PPP packet to the communication device 1-2 using the logical data link 2-2.

  Next, the operation proceeds to the operation of step S24, and the data dividing unit 13 subtracts the division unit length from the MP data length, and sets the subtracted length as the MP data length. Here, since the MP data length is 267 bytes and the division unit length is 134 bytes, the MP data length is 133 bytes.

  Then, the operation again proceeds to the operation of step S21, and the data dividing unit 13 compares the MP data length with the division unit length. Here, since the MP data length is 133 bytes and the division unit length is 134 bytes, the MP data length is equal to or less than the division unit length. The MP data having a length of 133 bytes is output to the encapsulation unit 14.

  The encapsulating unit 14 that has received the MP data having a length equal to or smaller than the division unit length output from the data dividing unit 13 adds the multilink PPP header and the MP header to the MP data having a length equal to or smaller than the received division unit length. A PPP packet is generated (step S25). Here, a 141-byte multilink PPP packet in which a 4-byte PPP header and a 4-byte MP header are added to 133 bytes, which is a length equal to or shorter than the division unit length, is generated.

  Then, the encapsulation unit 14 transmits the generated multilink PPP packet to the communication device 1-2 using the logical data link 2-3. (Step S26).

  As described above, the operations in steps S21 to S24 described above are repeatedly performed while the MP data length is longer than the division unit length.

  Thereafter, when the communication apparatus 1-1 subsequently receives an IP packet having a length of 400 bytes, 142-byte multilink PPP packets are similarly transmitted using the logical data links 2-1 and 2-2, and 141 bytes. Multi-link PPP packets are transmitted using the logical data link 2-3.

  The above is the operation in which the communication device 1-1 shown in FIG. 1 divides and transmits MP data according to the division unit length.

  FIG. 5 is a diagram showing step by step until a multilink PPP packet is generated from an IP packet received by the communication device 1-1 shown in FIG. 1 and FIG. The figure which shows the case where it divides | segments by payload length, (b) is a figure which shows the case where MP data is divided | segmented by division | segmentation unit length. In FIG. 5, the multilink PPP header is expressed as an MLPPP header.

  Comparing the multilink PPP packets shown at the bottom of FIG. 5A and FIG. 5B, in FIG. 5A, the length of the last multilink PPP packet is the length of another multilink PPP packet. It is extremely short compared to. On the other hand, in FIG. 5B, there is no significant difference between the length of the last multilink PPP packet and the length of other multilink PPP packets.

  FIG. 6 is a diagram illustrating an example of the length of a multilink PPP packet transmitted using each of the logical data links 2-1 to 2-3 set in the communication line 2 illustrated in FIG. (A) is a figure which shows the case where MP data is divided | segmented by the maximum MP payload length, (b) is a figure which shows the case where MP data is divided | segmented by division unit length. In FIG. 6, the IP packet length, MRU, and header length are the same as those shown in the operation flow described above.

  Comparing FIG. 6 (a) and FIG. 6 (b), in FIG. 6 (a), the MRU (200 bytes) is added to the logical data links 2-1 and 2-2, and the multilink PPP header (4 bytes) is added. A 204-byte multilink PPP packet is transmitted, and a 17-byte multilink PPP packet is transmitted to the logical data link 2-3. That is, the bandwidth usage rate of the logical data link 2-3 is fixed in a state lower than the bandwidth usage rates of the logical data links 2-1 and 2-2. On the other hand, in FIG. 6B, a 134-byte multilink PPP packet is transmitted to the logical data links 2-1 and 2-2, and a 133-byte multilink PPP packet is transmitted to the logical data link 2-3. Yes. That is, the usage rates of all the bands of the logical data links 2-1 to 2-3 are leveled.

  As described above, in the present embodiment, the communication apparatuses 1-1 and 1-2 are connected to the communication line 2 in which a plurality of logical data links 2-1 to 2-n are set, and packets transmitted from the packet transmitting side are transmitted. MP data to which a PPP header necessary for communication via the communication line 2 is added is generated. Further, the communication apparatuses 1-1 and 1-2 determine the number of divisions for dividing a packet based on the packet length and the MRU which is the maximum data length that can be received at one time by the packet receiving side. Calculate and divide the MP data by dividing by the number of divisions. Then, the communication devices 1-1 and 1-2 transmit each of the MP data divided using each of the plurality of logical data links 2-1 to 2 -n to the packet receiving side.

  Therefore, it is possible to avoid fixing the usage rate of the bandwidth of a specific logical data link in a state where it is lower than the usage rate of the bandwidth of another logical data link.

  In the present embodiment, the maximum MP payload length is calculated from the MRU, but the maximum MP payload length may be calculated from a value other than the MRU. For example, considering the transmission delay, a value obtained by subtracting the length of the multilink PPP header and the length of the MP header from the maximum packet length allowed for the multilink PPP packet may be set as the maximum MP payload length.

  In the present invention, the processing in the communication device is recorded on a recording medium that can be read by the communication device, in addition to the processing realized by the dedicated hardware described above. The program recorded on the recording medium may be read by the communication device and executed. The recording medium readable by the communication device refers to a transfer medium such as a flexible disk, a magneto-optical disk, a DVD, and a CD, as well as an HDD built in the communication device.

1-1, 1-2 Communication device 2, 4, 5 Communication line 2-1 to 2-n Logical data link 3-1, 3-2 Communication terminal 11 Division number calculation unit 12 Division unit length calculation unit 13 Data division unit 14 Encapsulation unit 15-1 to 15-n Communication IF

Claims (12)

A packet that is connected to a communication line and that is transmitted from a packet transmission side is divided, and each of the divided packets is received by using each of a plurality of logical data links set in the communication line. A communication device for transmitting to
The first data in which a header necessary for communication via the communication line is added to the packet transmitted from the packet transmitting side is generated, and the length of the packet and the receiving side of the packet can be received at one time A communication apparatus for dividing the first data by dividing the first data by calculating the number of divisions for dividing the packet based on the MRU which is the maximum data length. The communication device according to claim 1,
Encapsulation that generates the first data from a packet transmitted from the transmission side of the packet, and outputs the generated first data and a first data length that is the length of the first data And
The first data length output from the encapsulation unit is received, the division number is calculated according to the received first data length and the MRU, the calculated division number, and the first A division number calculation unit that outputs a data length of 1;
The first data is received by receiving the division number and the first data length output from the division number calculation unit, and dividing the received first data length by the received division number. A division unit length calculation unit that calculates a division unit length, which is a unit of length for dividing the image, and outputs the calculated division unit length;
The division unit length output from the division unit length calculation unit and the first data output from the encapsulation unit are received, and the received first data is divided according to the received division unit length. And a data dividing unit. The communication device according to claim 2,
The division number calculating unit calculates a second data length, which is a length obtained by subtracting a length of a header necessary for using the plurality of logical data links from the MRU, and calculates the calculated second data length. A communication device that calculates the number of divisions by dividing the first data length by a data length. The communication device according to claim 2,
The division number calculation unit calculates a second data length that is a length corresponding to a maximum packet length that can be transmitted using the logical data link, and uses the calculated second data length. A communication device that calculates the number of divisions by dividing the first data length. A packet that is connected to a communication line and that is transmitted from a packet transmission side is divided, and each of the divided packets is received by using each of a plurality of logical data links set in the communication line. A packet dividing method in a communication device for transmitting to
Processing for generating first data in which a header necessary for communication via the communication line is added to the packet transmitted from the packet transmission side;
A calculation process for calculating the number of divisions for dividing the packet based on the length of the packet and the MRU that is the maximum data length that can be received at one time by the receiving side of the packet;
A packet dividing method comprising: dividing the first data by dividing the first data by the number of divisions. The packet division method according to claim 5, wherein
The calculation process is as follows:
A process of calculating the number of divisions according to a first data length that is the length of the first data and the MRU;
The dividing process is
A process of calculating a division unit length, which is a unit of length for dividing the first data, by dividing the first data length by the number of divisions;
A process of dividing the first data according to the calculated division unit length. The packet division method according to claim 6, wherein
The calculation process is as follows:
A process of calculating a second data length, which is a length obtained by subtracting a length of a header required when using the plurality of logical data links from the MRU;
A process of calculating the number of divisions by dividing the first data length by the calculated second data length. The packet division method according to claim 6, wherein
The calculation process is as follows:
Processing to calculate a second data length that is a length according to a maximum packet length that can be transmitted using the logical data link;
A process of calculating the number of divisions by dividing the first data length by the calculated second data length. A packet that is connected to a communication line and that is transmitted from a packet transmission side is divided, and each of the divided packets is received by using each of a plurality of logical data links set in the communication line. To the communication device that transmits to
A function of generating first data in which a header necessary for communication via the communication line is added to the packet transmitted from the packet transmission side;
A calculation function for calculating the number of divisions for dividing the packet based on the length of the packet and the MRU which is the maximum data length that can be received at one time by the receiving side of the packet;
A program for realizing a division function of dividing the first data by dividing the first data by the number of divisions. The program according to claim 9,
The calculation function is
A function of calculating the number of divisions according to a first data length that is a length of the first data and the MRU;
The division function is
A function of calculating a division unit length, which is a unit of length for dividing the first data, by dividing the first data length by the number of divisions;
A function of dividing the first data according to the calculated division unit length. The program according to claim 10, wherein
The calculation function is
A function of calculating a second data length that is a length obtained by subtracting a length of a header required when using the plurality of logical data links from the MRU;
A function of calculating the number of divisions by dividing the first data length by the calculated second data length. The program according to claim 10, wherein
The calculation function is
A function of calculating a second data length that is a length according to a maximum packet length that can be transmitted using the logical data link;
A function of calculating the number of divisions by dividing the first data length by the calculated second data length.

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