JP2014049995A - Communication device, system and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a data transmission delay when a server and a client conform to a plurality of types of transmission systems.SOLUTION: A communication device includes: a first communication unit for communicating with a first communication device using a first transmission method; a second communication unit for communication using a second transmission method; an instruction unit for instructing the first and second communication units to perform processing for establishing a stream in a manner to overlap timing to perform stream establishment processing to be used by the first and second communication units; and a distribution unit for distributing transmission data to the first communication unit when the first communication unit first completes processing for establishing a single steam, and for changing distribution destinations of the transmission data after the second communication unit completes processing for establishing a plurality of streams.

Description

  Embodiments described herein relate generally to a communication device, a system, and a program.

  Conventionally, in a system including a server device and a client device connected via a network, TCP / IP is often used as a transmission protocol used for data transmission between the server device and the client device.

  When transmitting data using TCP / IP as a transmission protocol, the server passes data to the IP layer while controlling the data transmission rate (communication bandwidth) using the TCP stream in the TCP layer. The layer sends data to the network.

  Conventionally, a single TCP stream has been established between a server and a client device to perform data transmission. However, in recent years, a technique has been used in which a plurality of TCP streams are established between a server and a client device, divided into a plurality of data, and the divided data is transmitted in parallel. If a plurality of TCP streams are used, the data transmission rate can be improved.

  In order to correctly transmit and receive data, the server and the client need to support the same transmission method. For example, taking the transmission method using a plurality of TCP streams as described above as an example, if the communication partner only supports the transmission method using a single TCP stream, even if connection establishment is performed using a plurality of TCP streams. Because it fails, data transmission / reception cannot be started.

  Therefore, it becomes necessary to negotiate a transmission method corresponding to the server and the client device. However, in order to perform the negotiation, a procedure such as exchanging the type of transmission method corresponding to both parties is necessary, and it takes time until the negotiation is completed. For this reason, there is a problem in that a delay occurs until the data can be actually transmitted after the data needs to be transmitted. In addition, if a server or a client device that does not have such a negotiation mechanism is already widely used, it is difficult to add a negotiation function to these devices later.

JP 2003-8682 A US 2002/0099844

  An object of one aspect of the present invention is to reduce a data transmission delay due to negotiation when a server apparatus and a client apparatus support a plurality of types of transmission schemes.

A communication apparatus according to one aspect of the present invention is provided.
A device that communicates with a first communication device connected via a network, and performs processing for establishing a first connection, and the first communication device and the first connection Is established, the first communication unit that performs communication using the first transmission method and the process for establishing the second connection are performed, and the second connection is established with the first communication device. A second communication unit that performs communication using the second transmission method, a timing at which the first communication unit performs processing for establishing the first connection, and the second communication unit includes: Instructing the first communication unit to perform the process for establishing the first connection so that the timing for performing the process for establishing the second connection overlaps. And processing for establishing the second connection to the second communication unit An instruction unit that issues a second instruction; and a distribution unit, wherein the first communication unit sends a first message to the distribution unit when the process for establishing the first connection is completed. And the second communication unit notifies the distribution unit of a second message when the process for establishing the second connection is completed, and the distribution unit communicates the transmission data with the second message. Distribution of all the connections used for the first communication unit to the first communication unit or the second communication unit that is first completed, and the first communication unit first establishes the first connection. The transmission data is distributed to the first communication unit and the second communication unit completes the process for establishing the second connection, and then the transmission data The distribution destination of the network from the first communication unit to the second communication unit And wherein the door.

1 is a block diagram showing a system according to a first embodiment of the present invention. The figure which shows a mode that data is divided | segmented and the header showing a division | segmentation order is provided. The sequence diagram which shows an example of the flow of a process of the system which concerns on 1st Embodiment. It is a block diagram which shows the system concerning the modification of the 1st Embodiment of this invention. It is a block diagram which shows the system concerning the 2nd Embodiment of this invention. It is a figure which shows an example of a screen update. It is a figure for demonstrating area | region information. It is a figure which shows an example of division information. 6 is a flowchart showing processing of a fifth distribution unit 3202 of the server device 32 of FIG. 5. It is a figure which shows the flowchart of the 1st example of the determination process of the number of streams. FIG. 6 is a diagram illustrating a first example of a table held by a storage unit 32061 of a stream number determination unit 3206 of the server device 32 of FIG. 5. It is a figure which shows the flowchart of the 2nd example of the determination process of the number of streams. FIG. 6 is a diagram illustrating a second example of a table held by the storage unit 32061 of the stream number determination unit 3206 of the server device 32 of FIG. 5. It is a figure which shows the flowchart of the 3rd example of the determination processing of the number of streams.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
In the first embodiment, it is assumed that the server device and the client device respectively correspond to one or both of a transmission method using a single TCP stream and a transmission method using a plurality of TCP streams. The transmission method need not be limited to these. Three or more types may be used.

  FIG. 1 is a block diagram illustrating a configuration of a system according to the first embodiment. In the system of FIG. 1, a client device 1 and a server device 2 are connected via a network 3. The client apparatus 1 and the server apparatus 2 are apparatuses that establish one or more TCP streams and perform communication using the established TCP streams.

    The client device 1 according to one aspect of the present invention is a device that communicates with the first server device 2 connected via the network 3 and performs processing for establishing a single stream, When the server apparatus 2 and the single stream are established, the first transmission unit 103 that performs communication using the single stream, a process for establishing a plurality of streams, and the server apparatus 2 When the plurality of streams are established, a timing at which the second transmission unit 104 that performs communication using the plurality of streams and the first transmission unit 103 perform processing for establishing the single stream And the second transmitter 104 to the first transmitter 103 such that the timing at which the second transmitter 104 performs processing for establishing the plurality of streams overlaps. Establishment that issues a first instruction to perform processing for establishing a stream and issues a second instruction to perform processing for establishing the plurality of streams to the second transmission unit 104 An instruction unit 101 and a first distribution unit 102; the first transmission unit 103 sends a first message to the first distribution unit 102 when the processing for establishing the single stream is completed. The second transmission unit 104 notifies the first distribution unit 102 of the second message when the processing for establishing the plurality of streams is completed, and the first distribution unit 102 The data is distributed to either the first transmission unit 103 or the second transmission unit 104 that has first completed the establishment of all streams used for communication, and the first transmission unit 103 Single stream The transmission data is distributed to the first transmission unit 103 and the second transmission unit 104 completes the processing for establishing the plurality of streams. The distribution destination of the transmission data is switched from the first transmission unit 103 to the second transmission unit 104.

  Below, the structure of the client apparatus 1 and the server apparatus 2 is demonstrated using FIG.

≪ Client device configuration ≫

The client device 1 includes a data supply unit 100, an establishment instruction unit 101, a first distribution unit 102, a first transmission unit 103, and a second transmission unit 104. The first transmission unit 103 includes an establishment unit 105. The second transmission unit 104 includes an establishment unit 106 and a second distribution unit 107.

  The data supply unit 100 supplies data to be transmitted to the server device 2.

The establishment instruction unit 101 instructs establishment of a connection between the server device 2 using the establishment unit 105 of the first transmission unit 103 and the establishment unit 106 of the second transmission unit 104. (Each instruction for the establishing unit 105 and the establishing unit 106 is referred to as a first instruction and a second instruction.)
The first distribution unit 102 passes the data delivered from the data supply unit 100 to the first transmission unit 103 or the second transmission unit 104, and instructs data transmission.

  The first transmission unit 103 performs data transmission by the first transmission method. In the present embodiment, the first transmission method is a transmission method using a single TCP stream.

  The second transmission unit 104 performs data transmission by the second transmission method. In the present embodiment, the second transmission method is a transmission method using a plurality of TCP streams.

  The establishment unit 105 establishes connection in the first transmission method. Specifically, the establishing unit 105 creates a single TCP stream with the first receiving unit 200 of the server device 2.

  The establishment unit 106 establishes connection in the second transmission method. Specifically, the establishing unit 106 first creates a control TCP stream with the second receiving unit 201 of the server device 2. Next, the establishing unit 106 exchanges information regarding creation of a plurality of TCP streams for data using the control TCP stream, and creates a data TCP stream using the exchanged information.

  The second distribution unit 107 performs data distribution in the second transmission method. Specifically, the second distribution unit 107 divides the data delivered from the first distribution unit 102, adds a header indicating the division order, and performs transmission to a plurality of TCP streams. Details of the operation of the dividing unit 107 will be described later with reference to FIG.

  The above is the description of the configuration of the client device 1.

≪ Server device configuration ≫

Next, the configuration of the server device 2 will be described.

  The server device 2 includes a first receiving unit 200, a second receiving unit 201, a second collecting unit 205, and a data output unit 206. The first receiving unit 200 includes a standby unit 202. The second reception unit 201 includes a standby unit 203 and a first collection unit 204.

  The first receiving unit 200 receives data according to the first transmission method.

  The second receiving unit 201 receives data by the second transmission method.

  The standby unit 202 performs connection standby in the first transmission method. Specifically, the standby unit 202 creates a TCP stream with the first transmission unit 103 of the client device 1.

  The standby unit 203 performs connection standby in the second transmission method. Specifically, the standby unit 203 creates a control TCP stream with the second transmission unit 104 of the client device 1, and uses this control TCP stream to create information about the creation of the data TCP stream. After the exchange, a plurality of data TCP streams are created.

  The first collection unit 204 collects data in the second transmission method. Specifically, the first collection unit 204 reproduces the data before division based on the header representing the division information added to the data received from the second transmission unit 104 and passes the data to the second collection unit 205.

  The second collection unit 205 collects data passed from the first reception unit 200 or the second reception unit 201 and passes it to the data output unit 206.

  The data output unit 206 outputs the data passed from the second collection unit 205.

  The above is the description of the configuration of the server device 2.

≪Process flow≫

Next, processing performed by the system according to the first embodiment will be described with reference to the drawings as appropriate.

  A client device 1 and a server device 2 are physically connected via a network 3. It is assumed that the first transmission method is a transmission method using a single TCP stream, and the second transmission method is a transmission method using a plurality of TCP streams. In addition, when both the client apparatus 1 and the server apparatus 2 support a transmission method using a plurality of TCP streams, the client apparatus 1 and the server apparatus 2 are preferentially used.

≪ Process flow (connection establishment) ≫

First, the server device 2 performs a connection standby process. The start timing of the standby process may be an arbitrary timing such as a timing when the server device 2 is activated or a timing when an explicit instruction is given from the user. The standby unit 202 of the first receiving unit 200 and the standby unit 203 of the second receiving unit 201 each start a standby process. The waiting unit 202 creates a socket, assigns a unique port number of the first receiving unit 200 to the socket, opens the port, and waits for a connection from the client device 1. The standby unit 203 also creates a socket, assigns a unique port number of the second reception unit 201 to the socket, opens the port, and waits for a connection from the client device 1.

  Next, the establishment instruction unit 101 of the client device 1 performs connection establishment processing. The start timing of the establishment process may be an arbitrary timing such as a timing when an explicit instruction is given from the user or a timing when data to be transmitted is generated in the data supply unit 100. The establishment instruction unit 101 instructs the establishment unit 105 of the first transmission unit 103 and the establishment unit 106 of the second transmission unit 104 to start connection establishment processing.

  In the present embodiment, the establishment unit 105 and the establishment unit 106 are instructed to start connection establishment processing at the same timing. However, the present invention is not necessarily limited to this. A time difference may be generated at the timing of issuing the instruction.

  The establishment unit 105 sends SYN to the port opened by the standby unit 202, and establishes a TCP connection by a three-way handshake. After exchanging SYN and ACK (acknowledgment response), a TCP stream is created between the two. When the creation of the TCP stream is completed, the establishing unit 105 notifies the establishment instructing unit 101 that the connection has been successfully established.

  The establishing unit 106 sends SYN to the port opened by the standby unit 203 and establishes a TCP connection by a three-way handshake. After exchanging SYN and ACK, a TCP stream is created between the two. In the second transmission unit 104, this TCP stream is called a control TCP stream. When the creation of the control TCP stream is completed, the establishing unit 106 uses this control TCP stream to exchange information regarding the creation of the data TCP stream. First, the establishing unit 106 sends an acquisition request for the port number used in the data TCP stream to the standby unit 203. When receiving the acquisition request, the standby unit 203 selects an arbitrary port at the server device 2 at that time, selects the requested number of port numbers, and assigns it to the data TCP stream. The standby unit 203 creates the requested number of sockets, assigns the selected port number to each socket, and opens the ports. Then, information on the list of opened port numbers is sent to the establishing unit 106. Next, when the establishment unit 106 receives the port number list information, the establishment unit 106 establishes a TCP connection to these ports by a three-way handshake. When the SYN / ACK is exchanged and the TCP stream is created, the establishment unit 106 notifies the establishment instruction unit 101 that the connection has been successfully established.

  In the present embodiment, the standby unit 203 selects an arbitrary port when creating the data TCP stream, but the present invention is not necessarily limited to this. The standby unit 203 may further include a port management unit for managing port numbers in the server device 2, and may search for and use unused port numbers in the server device 2. As a result, it is possible to reduce the possibility that connection establishment will fail because the selected port number is already in use.

  The standby unit 203 may further include a transmission rate management unit that manages the data transmission rate in the second reception unit 201. The server device 2 may acquire the speed of data transmission performed by another application, and may limit the number of data TCP streams based on this value. Alternatively, the transmission rate achievable in each data TCP stream may be limited by an arbitrary method.

≪ Processing flow (data transmission) ≫

The connection establishment process in the first transmission unit 103 and the connection establishment process in the second transmission unit 104 are executed in parallel. For this reason, the establishment instructing unit 101 receives notifications of connection establishment results in order from the one that has been completed first. The establishment instructing unit 101 executes different processing procedures when the connection establishment of the first transmission unit 103 is completed first and when the connection establishment of the second transmission unit 104 is completed first. Below, the processing procedure of the establishment instruction | indication part 101 is described about each case.

A case where the connection of the first transmission unit 103 is completed first will be described with reference to FIG. FIG. 3 is a sequence diagram illustrating an example of a process flow of the system according to the first embodiment.
When the establishment instruction unit 101 receives a notification from the establishment unit 105 that the connection has been successfully established, the establishment instruction unit 101 instructs the first distribution unit 102 to set the data distribution destination to the first transmission unit 103. Next, the establishment instructing unit 101 notifies the data supply unit 100 that data can be transmitted, and thereafter, data is input from the data supply unit 100. The data supply unit 100 passes the data to the first distribution unit 102. The first distribution unit 102 passes the data to the first transmission unit 103. Here, the first distribution unit 102 has a storage area for holding the cumulative value of the data size passed to the first transmission unit 103, and every time data is passed to the first transmission unit 103, Is added to the value in the storage area. This value is called the accumulated transmitted data size. The data passed to the first transmission unit 103 is provided with each TCP / IP header and is transmitted to the first reception unit 200 through a TCP stream. Further, the data is passed to the second collection unit 205. The second collection unit 205 passes the received data to the data output unit 206. Here, the second collection unit 205 has a storage area for holding the cumulative value of the data size received from the first reception unit 200, and stores the value of the data size every time data is received. Add to the region value. This value is called the cumulative received data size. The data output unit 206 outputs the obtained data by an arbitrary method. Thereafter, each time data is input from the data supply unit 100, the data is finally transmitted to the data output unit 206 by the above processing.

  Next, the connection of the second transmission unit 104 is completed thereafter. When the establishment instruction unit 101 receives a notification from the establishment unit 106 that the connection has been successfully established, the establishment instruction unit 101 sends the data distribution destination from the first transmission unit 103 to the second transmission unit 104 to the first distribution unit 102. And instruct to switch. Thereafter, when the first distribution unit 102 receives data to be transmitted from the data supply unit 100, the first distribution unit 102 passes the data to the second distribution unit 107 of the second transmission unit 104. The data delivered to the second distribution unit 107 is divided, a header indicating the division order is added, and each header of TCP / IP is further added, and the second data is sent in parallel through a plurality of data TCP streams. The data is sent to the first collection unit 204 of the reception unit 201. FIG. 2 shows how data is divided and a header indicating the division order is given. In the figure, the data is divided into four, and a header consisting of a serial number from 1 to 4 and the number of divisions is added to each. This information is called division information. The divided data is allocated to a plurality of data TCP streams by an arbitrary method and transmitted. The received data is passed to the first collection unit 204. The order of data transmitted in a single TCP stream is guaranteed, but when the data is divided into a plurality of TCP streams, the order between the streams is not guaranteed. Therefore, the first collection unit 204 refers to the division information, performs rearrangement so that the order is correct to the original order, and then passes the data to the second collection unit 205. The header indicating the division order is removed.

  Further, the establishment instructing unit 101 reads out the accumulated transmitted data size value passed from the first distributing unit 102 to the first transmitting unit 103 in response to issuing an instruction to switch the data distribution destination. The establishment instruction unit 101 notifies the second transmission unit 104 of this value, and instructs the second reception unit 201 to notify this value through the control TCP stream. The value notified to the second receiving unit 201 is further notified to the second collecting unit 205. Here, the second collection unit 205 outputs the data received from the second reception unit 201 until the notified value of the accumulated transmitted data size becomes equal to the value of the accumulated received data size of itself. It is not passed to the unit 206 but held by itself. That is, it waits for delivery of data transmitted using the second transmission method until it receives all data transmitted using the first transmission method. All the data received from the second receiving unit 201 is received by the data output unit 206 at the timing when the notified value of the accumulated transmitted data size becomes equal to the value of the accumulated received data size of itself. hand over. By doing in this way, it becomes possible to eliminate the difference in the arrival order of data that has occurred between the first transmission method and the second transmission method.

  The case where the connection of the first transmission unit 103 is completed first has been described above.

  Next, a case where the connection of the second transmission unit 104 is completed first will be described. When the establishment instruction unit 101 receives a notification from the establishment unit 106 that the connection has been successfully established, the establishment instruction unit 101 instructs the first distribution unit 102 to change the data distribution destination to the second transmission unit 104. Next, the establishment instructing unit 101 notifies the data supply unit 100 that data transmission is possible. Thereafter, the data in the data supply unit 100 is distributed by the first distribution unit 102 to the second transmission unit 104 (the second distribution unit 107). The processing procedure until the distributed data is finally transmitted to the second collection unit 205 in accordance with the second transmission method is the same as described above. The second collection unit 205 passes the received data to the data output unit 206.

  In this embodiment, the transmission method using a single TCP stream by the first transmission unit 103 is given priority over the transmission method using a plurality of TCP streams by the second transmission unit 104. Therefore, the establishment instruction unit 101 no longer needs to use the first transmission method at the timing of receiving the notification of the completion of connection of the second transmission unit 104. Therefore, the establishment instruction unit 101 instructs the first transmission unit 103 to interrupt connection establishment at this timing. The first transmitting unit 103 terminates sockets and releases resources such as ports. Alternatively, the connection establishment is not interrupted at the timing when the notification is received, but is waited until the connection of the first transmission unit 103 is completed, and the connection of the first transmission unit 103 is immediately terminated when the connection is completed. The operation may be as follows.

  The case where the connection of the second transmission unit 104 is completed first has been described above.

  In the present embodiment, the first transmission unit 103 and the second transmission unit 104 operate independently of each other. However, the present invention is not limited to this, and data transmission is performed by one transmission unit. Information acquired in the meantime may be passed to the other transmitter. An example is shown. Now, in the client device 1, the connection establishment of the first transmission unit 103 is completed, the connection establishment of the second transmission unit 104 is not completed, and the data input from the data supply unit 100 is the first transmission unit. It is assumed that the status is being transmitted to the server apparatus 2 through 103. At this time, the first transmission unit 103 measures the data transmission rate of the TCP stream with the first reception unit 200 and holds it in itself. Furthermore, it is assumed that the connection establishment of the second transmission unit 104 is completed thereafter. When the establishment instruction unit 101 receives a notification of successful connection establishment from the second transmission unit 104, the establishment instruction unit 101 inquires of the first transmission unit 103 about the value of the accumulated transmitted data size and the value of the data transmission rate. . The establishment instruction unit 101 notifies both values to the establishment unit 106 of the second transmission unit 104. The establishment unit 106 can adjust the number of data transmission TCP streams using the notified data transmission rate value. For example, a value obtained by dividing a specified value (a value of a data transmission rate desired to be realized in the second transmission unit 104) by a notified data transmission rate is set as the number of data transmission TCP streams, and the data already established Control may be performed so that only this number of streams among the TCP streams is used thereafter. As described above, the information regarding the characteristics of the server device 2 and the network 3 acquired by the first transmission unit 103 is notified to the second transmission unit 104, and the second transmission unit 104 uses the information to thereby obtain these characteristics. Accordingly, the operation of the second transmission unit 104 can be adaptively adjusted. Note that the information to be measured / notified is not limited to the data transmission rate. For example, it may be information related to the characteristics of the network 3 such as data transmission delay and IP packet loss probability, or information related to the first transmission unit 103 and the first reception unit 200 such as the window size of the TCP stream.

  Alternatively, control may be performed so that the TCP stream used in the first transmission unit 103 is reused in the second transmission unit 104. An example is shown. Similarly to the above, it is assumed that connection establishment in the second transmission unit 104 is completed while the client device 1 is performing data transmission by the first transmission unit 103. When the establishment instruction unit 101 receives a successful connection establishment from the second transmission unit 104, the establishment instruction unit 101 inquires of the first transmission unit 103 about the value of the accumulated transmission data transmission size and is used by the first transmission unit 103. The client device 1 inquires about the identifier value of the TCP stream to be executed. The establishment instruction unit 101 notifies the second transmission unit 104 of both values. The second transmission unit 104 stores the notified identifier of the TCP stream, and thereafter handles this stream in the same manner as the data stream. That is, the TCP stream of the first transmission unit 103 is reused as a data stream. As a result, it is possible to reduce the processing load associated with the creation of the TCP stream.

≪ When only one transmission method is supported ≫

Next, an operation when either the client device 1 or the server device 2 is not compatible with the second transmission method will be described.

  First, an operation in the case where the server apparatus 2 supports only the first transmission method and does not support the second transmission method will be described. It is assumed that the client device 1 supports both transmission methods.

  When the server device 2 does not support the second transmission method, the second receiving unit 201 does not exist in the server device 2. In the connection waiting process, the server device 2 is in a state in which only the waiting unit 202 of the first receiving unit 200 opens a port and waits for a connection from the client device 1.

  The connection establishment process in the establishment instruction unit 101 of the client apparatus 1 is the same as described above, and the connection establishment process is performed in each of the establishment unit 105 of the first transmission unit 103 and the establishment unit 106 of the second transmission unit 104. Is started. Here, SYN is sent to both the port corresponding to the first transmission method and the port corresponding to the second transmission method. Among these, regarding the first transmission method, since the standby unit 202 of the first receiving unit 200 has the port open, TCP connection establishment by the three-way handshake is successful. On the other hand, regarding the second transmission method, since the corresponding port is not opened, TCP connection establishment fails. The establishment unit 106 notifies the establishment instruction unit 101 that connection establishment has failed. At this time, the establishment instruction unit 101 receives a notification of successful connection establishment from the first transmission unit 103 and receives a notification of connection establishment failure from the second transmission unit 104. In the present embodiment, the establishment instructing unit 101 starts data transmission by the first transmission method at the timing when the notification of connection establishment success is received, and does not perform any special processing at the timing when the notification of connection establishment failure is received. To do.

  Next, an operation when the client device 1 supports only the first transmission method and does not support the second transmission method will be described. It is assumed that the server apparatus 2 is compatible with both transmission methods.

  When the client device 1 does not support the second transmission method, the second transmission unit 104 does not exist in the client device 1. In the connection establishment process, the client device 1 attempts to establish a TCP connection only with respect to the first receiving unit 200 of the server device 2. When this connection establishment is successful and the establishment instructing unit 101 receives a notification of success, data transmission from the data supply unit 100 is performed through the first transmission unit 103 thereafter.

  The operation when either the client device 1 or the server device 2 is not compatible with the second transmission method has been described above.

<Modification of First Embodiment>
FIG. 4 is a block diagram showing a system according to a modification of the first embodiment.

  The system according to the first embodiment has been described for the case where the client device 1 transmits data and the server device 22 receives data. In the system according to the modification of the first embodiment, a case where the client device 21 receives data and the server device 22 transmits data will be described. The client device 21 and the server device 22 according to the modification of the first embodiment are the same as those in the first embodiment, except that the client device and the server device are different from the first embodiment in the transmission / reception side. It is the same as the form.

  4, the client device 21 includes a data supply unit 110, an establishment instruction unit 111, a third collection unit 112, a first reception unit 113, and a second reception unit 114.

  The server device 22 includes a first transmission unit 210, a second transmission unit 211, a standby unit 215, a fourth distribution unit 216, and a data supply unit 217.

  Here, the establishment instruction unit 111, the establishment unit 115, and the establishment unit 116 of the client device 21 perform the same operations as in the first embodiment. Further, the first standby unit 212, the standby unit 215, and the standby unit 213 of the server device 22 perform the same operations as in the first embodiment.

  First, the server device 22 performs a connection standby process. This is the same operation as in the first embodiment. The standby unit 212 of the first transmission unit 210 and the standby unit 213 of the second transmission unit 211 each allocate a unique port number to the socket, open the port, and wait for a connection from the client device 21.

  Next, the establishment instruction unit 111 of the client device 21 performs connection establishment processing. The establishment instruction unit 111 instructs the establishment unit 115 of the first reception unit 113 and the establishment unit 116 of the second reception unit 114 to start connection establishment processing. Each connection establishment process is performed in parallel. The establishment unit 115 attempts to establish a TCP connection with the standby unit 212. When the creation of the TCP stream is completed, the establishment unit 115 notifies the establishment instruction unit 111 that the connection has been successfully established. Similarly, the establishing unit 116 attempts to establish a TCP connection with the standby unit 213. When the creation of the TCP stream (control TCP stream) is completed, the establishing unit 116 then exchanges information regarding the creation of the data TCP stream with the standby unit 213 using the control stream. First, the establishing unit 116 sends an acquisition request for the port number used in the data TCP stream to the standby unit 213. When the standby unit 213 receives the acquisition request, the standby unit 213 checks ports that are not used in the server device 22 at that time, selects an arbitrary number of port numbers, and assigns them to the data TCP stream. The standby unit 213 creates a selected number of sockets, assigns the selected port number to each socket, and opens the ports. Then, information on the list of opened port numbers is sent to the establishing unit 116. Next, upon receiving the port number list information, the establishing unit 116 establishes a TCP connection to these ports. When the data TCP stream is created, the establishment unit 116 notifies the establishment instruction unit 111 that the connection has been successfully established.

  When the standby unit 212 of the first transmission unit 210 completes the creation of the TCP stream with the establishing unit 115, the standby unit 212 notifies the standby unit 215 that the connection has been successfully established. Similarly, when the standby unit 213 of the second transmission unit 211 completes the creation of the data TCP stream with the establishing unit 116, the standby unit 215 notifies the standby unit 215 that the establishment of the connection has been completed.

  The connection establishment process in the first transmission unit 210 and the connection establishment process in the second transmission unit 211 are executed in parallel. Therefore, the standby unit 215 receives notifications of connection establishment results in order from the one that has been completed first. The standby unit 215 executes different processing procedures when the connection establishment of the first transmission unit 210 is completed first and when the connection establishment of the second transmission unit 211 is completed first. Hereinafter, the processing procedure of the standby unit 215 will be described for each case.

  A case where the connection of the first transmission unit 210 is completed first will be described. When the standby unit 215 receives notification from the standby unit 212 that the connection has been successfully established, the standby unit 215 instructs the fourth distribution unit 216 to use the first transmission unit 210 as a data distribution destination. Next, the standby unit 215 notifies the data supply unit 217 that the data can be transmitted, and thereafter, data is input from the data supply unit 217. The data supply unit 217 passes the data to the fourth distribution unit 216. The fourth distribution unit 216 passes the data to the first transmission unit 210. Here, the fourth distribution unit 216 has a storage area for holding the cumulative value of the data size passed to the first transmission 210, and every time data is passed to the first transmission unit 210, The data size value is added to the storage area value. This value is called the accumulated transmitted data size. The data passed to the first transmission unit 210 is provided with each TCP / IP header and is transmitted to the first reception unit 113 through a TCP stream. Further, the data is passed to the third collection unit 112. The third collection unit 112 passes the received data to the data output unit 110. Here, the third collection unit 112 has a storage area for holding the cumulative value of the data size received from the first reception unit 113, and stores the value of the data size every time data is received. Add to the region value. This value is called the cumulative received data size. The data output unit 110 outputs the obtained data by an arbitrary method. Thereafter, every time data is input from the data supply unit 217, the data is finally transmitted to the data output unit 110 by the above processing.

  Next, the connection of the second transmission unit 211 is completed thereafter. When receiving a notification from 213 that the connection has been successfully established, standby unit 215 switches the data distribution destination from first transmission unit 210 to second transmission unit 211 for fourth distribution unit 216. Give instructions to do so. Thereafter, when the fourth distribution unit 216 receives data to be transmitted from the data supply unit 217, the fourth distribution unit 216 passes the data to the third distribution unit 214 of the second transmission unit 211. The data passed to the third distribution unit 214 is divided, a header indicating the division order is added, and each header of TCP / IP is added, and the second data is sent in parallel through a plurality of data TCP streams. The data is sent to the fourth collection unit 117 of the reception unit 114. The fourth collection unit 117 refers to the division information, performs rearrangement so that the order is correct to the original order, and then passes the data to the third collection unit 112.

  Further, the standby unit 215 reads the accumulated transmitted data size value passed from the fourth distribution unit 216 to the first transmission unit 210 in response to issuing an instruction to switch the data distribution destination. The standby unit 215 notifies the second transmission unit 211 of this value and instructs the second reception unit 114 to be notified of this value through the control TCP stream. The value notified to the second receiving unit 114 is further notified to the third collecting unit 112. Here, the third collection unit 112 outputs the data received from the second reception unit 113 until the notified value of the accumulated transmitted data size becomes equal to the value of the accumulated received data size of itself. It does not pass to the unit 110 but keeps itself. That is, it waits for delivery of data transmitted using the second transmission method until it receives all data transmitted using the first transmission method. The data output unit 110 receives all the data received from the second receiving unit 114 at the timing when the notified value of the accumulated transmitted data size is equal to the value of the accumulated received data size held by itself. hand over. By doing in this way, it becomes possible to eliminate the difference in the arrival order of data that has occurred between the first transmission method and the second transmission method.

  The case where the connection of the first transmission unit 210 is completed first has been described above.

  Next, a case where the connection of the second transmission unit 211 is completed first will be described. When the standby unit 215 receives a notification from the standby unit 213 that the connection has been successfully established, the standby unit 215 instructs the fourth distribution unit 216 to set the data distribution destination as the second transmission unit 211. Next, the standby unit 215 notifies the data supply unit 217 that data can be transmitted. Thereafter, the data of the data supply unit 217 is distributed by the fourth distribution unit 216 to the second transmission unit 211 (the third distribution unit 214 thereof). The processing procedure until the distributed data is finally transmitted to the third collection unit 112 in accordance with the second transmission method is the same as described above. The third collection unit 112 passes the received data to the data output unit 110.

  In this embodiment, the transmission method using a single TCP stream by the first transmission unit 210 is given priority over the transmission method using a plurality of TCP streams by the second transmission unit 211. Therefore, the standby unit 215 no longer needs to use the first transmission method at the timing of receiving the connection completion notification of the second transmission unit 211. Therefore, the standby unit 215 instructs the first transmission unit 210 to interrupt connection establishment at this timing. The first transmission unit 210 releases resources such as socket termination and port. Alternatively, at the timing when the notification is received, the connection establishment is not interrupted, but waits until the connection of the first transmission unit 210 is completed, and the connection of the first transmission unit 210 is immediately terminated when the connection is completed. It may be an action.

  The case where the connection of the second transmission unit 211 is completed first has been described above.

  As described above, according to the first embodiment, according to the difference in the priority between the specifications of the first transmission method and the second transmission method, the transmission method with the lower priority (first transmission method) is the first. When the connection establishment is completed, data transmission is started using that, and when a transmission method with a high priority (second transmission method) is completed later, the subsequent data transmission is performed by switching to that, When a high-priority transmission method completes connection establishment first, it continues to use it. As a result, when the client device and the server device support a plurality of types of transmission methods, data transmission can be started when the connection completion is completed earlier, so that the time required for data transmission can be shortened. It becomes possible. In addition, a transmission method with a high priority can be used in accordance with each corresponding situation.

Furthermore, according to the present embodiment, even when a server device or a client device that does not have a mechanism for negotiating the correspondence status to the transmission method is already widely used, it is necessary to add a negotiation mechanism later. Absent.

In the client 1 device and the server device 2 according to the first embodiment, the first transmission method is a transmission method in which communication is performed using a single stream, and the second transmission method is performed using a plurality of streams. Although an example of a transmission method for performing communication has been described, the first transmission method and the second transmission method are not limited to this example. The first transmission method and the second transmission method may be different transmission methods. For example, in addition to a transmission method based on a protocol such as DCCP (Datagram Control Control Protocol) or SCTP (Stream Control Transmission Protocol), a transmission method based on ATM or a frame relay may be used. Further, a transmission method that includes a procedure such as authentication in connection establishment, such as TLS (Transport Layer Security), may be used. In this case, the second transmission unit 104 and the second reception unit 201 may establish a single stream and perform communication using the single stream. In this case, the second transmission unit 104 may not include the second distribution unit 107, and the second reception unit 201 may not include the first collection unit 204. Further, the first transmission method or the second transmission method may be a transmission method using a connectionless protocol such as UDP (User Datagram Protocol). In the case of including a connectionless transmission method, for example, the first transmission method is a transmission method that performs communication using UDP, and the second transmission method is a transmission method that performs communication using TCP. Since UDP is a transmission protocol that does not have a connection establishment procedure, in this case, the first transmission unit 103 may not include the establishment unit 105. The first receiving unit 200 may not include the standby unit 202. In that case, when performing the connection establishment process, the establishment instruction unit 101 omits the step of instructing the first transmission unit 103 to start the connection establishment process, and the connection establishment process is completed at that time. Behave as if In other words, the establishment instruction unit 101 instructs the first distribution unit 102 to set the data distribution destination to the first transmission unit 103, and further allows data to be transmitted to the data supply unit 100. Notify that.

  The client device 1 can also be realized by using, for example, a general-purpose computer device as basic hardware. In other words, the data supply unit 100, the establishment instruction unit 101, the first distribution unit 102, the first transmission unit, and the second transmission unit 104 are realized by causing a processor mounted on the computer device to execute a program. be able to. At this time, the client device 1 may be realized by installing the above program in a computer device in advance, or may be stored in a storage medium such as a CD-ROM or distributed through the network. Thus, this program may be realized by appropriately installing it in a computer device.

  The server device 2 can also be realized by using, for example, a general-purpose computer device as basic hardware. That is, the first receiving unit 200, the second receiving unit 201, the second collecting unit 205, and the data output unit 206 can be realized by causing a processor mounted on the computer device to execute a program. At this time, the server device 2 may be realized by installing the above program in a computer device in advance, or may be stored in a storage medium such as a CD-ROM or distributed through the network. Thus, this program may be realized by appropriately installing it in a computer device.

  Similarly, the client device 21 and the server device 22 can also be realized by using a general-purpose computer device as basic hardware.

<Second Embodiment>
FIG. 5 is a block diagram showing a system according to the second embodiment of this invention.

  In the following description, it is assumed that the system of the second embodiment is a “screen transfer system” that packetizes server screen information and distributes it in real time. However, the system of the second embodiment can be applied not only to the screen transfer system but also to a system that performs any kind of data transmission.

  As shown in FIG. 5, in the system according to the second embodiment, a server device 32 and a client device 31 are connected via a network 3.

The server device 32 according to the second embodiment generates a plurality of first divided data by dividing the first data with the plurality of transmission units 3203A to Z3Z, Transmission required for the fifth distribution unit 3202 to distribute to the plurality of transmission units 3203A to Z and the plurality of transmission units 3203A to Z to transmit the first data to the client device 31 in an arbitrary period. A transmission processing time calculation unit 3205 that calculates a transmission processing time rate, which is a ratio of processing time, and a plurality of second data that the fifth distribution unit 3202 generates by dividing the second data based on the transmission processing time rate A number-of-streams determination unit 3206 that determines how many transmission units the divided data is distributed to, and the fifth distribution unit 3202 transmits a plurality of pieces of second divided data in the number determined by the determination unit 3206. Characterized in that it distributed.

  Hereinafter, first, the reason for determination will be described based on the transmission processing time rate when the number-of-streams determination unit 3206 determines the number of transmission units to be distributed to the fifth distribution unit 3202.

  In general, when data transmission is performed using a plurality of TCP streams, it can be said that it is preferable to determine an appropriate number of streams (the number of transmission units in FIG. 5). If the number of TCP streams is increased, the data transmission rate is improved. However, when the transmission rate exceeds the network bandwidth, there is no change in the transmission rate even if the number of TCP streams is further increased. On the other hand, as the number of TCP streams increases, the processing load on the apparatus increases. Therefore, it is necessary to set the number of TCP streams to an appropriate value in order to ensure a transmission rate and not apply unnecessary processing load.

  Conventionally, as a method for determining the number of TCP streams, for example, the number of TCP streams is increased by one, the transmission rate is measured for each number of the TCP streams, and the TCP stream is determined according to the measured value of the transmission rate. There was a way to determine the number. For example, when the number of TCP streams is increased from N to N + 1, and the measured value of the transmission rate does not change or decreases, a method of determining the number of TCP streams to N is considered. It is done. When the number of TCP streams is N + 1, it is determined that the transmission rate that can be achieved with N + 1 exceeds the network bandwidth, and even if it is increased further, the processing load will increase and the transmission rate will not increase. is there.

  However, with this method, the number of TCP streams may not be set to an appropriate value.

  The transmission rate is also affected by the amount of data to be transmitted. Therefore, when the amount of data to be transmitted is small, the transmission rate is reduced even if the number of TCP streams is increased. That is, when the amount of data to be transmitted is small, the measured transmission rate may be smaller than the realizable transmission rate of the TCP stream.

  Thus, the measurement value of the transmission rate used for determining the number of TCP streams may be significantly lower than the feasible transmission rate of the TCP stream. In such a case, the above-described determination method may not be able to set the number of TCP streams to an appropriate value.

  For example, when the number of TCP streams is increased from N to N + 1, if the transmission rate measurement value does not change or decreases, the cause is that the transmission rate exceeds the network bandwidth. Instead, the amount of data to be transmitted may be small. In such a case, N + 1 or more TCP streams may be determined to be N in spite of proper values.

  Therefore, if the number of TCP streams is determined only by the measurement value of the transmission rate, the number of TCP streams may not be determined appropriately.

  When determining the number of TCP streams, the measured value of the transmission rate used as a criterion is compared with the measured value when transmitting a data amount that can realize a feasible transmission rate in the number of TCP streams. Preferably there is.

  One aspect of the present invention is an unnecessary aspect of securing the transmission rate as the number of TCP streams used between the server apparatus and the client apparatus even when the amount of data to be transmitted between the server apparatus and the client apparatus changes. The aim is to be able to determine an appropriate number of TCP streams that do not cause processing load.

  Therefore, in this embodiment, when the number of streams is determined (how many transmission units are distributed), the number is determined based on the transmission processing time rate.

≪ Server device configuration ≫

Next, the configuration of the server device 32 according to the present embodiment will be described with reference to FIG.

  The server apparatus 32 includes a data supply unit 3201, a fifth distribution unit 3202, a plurality of transmission units 3203A to 3203Z, a transmission rate measurement unit 3204, a transmission processing time rate calculation unit 3205, and a stream number determination unit 3206. Prepare.

  The data supply unit 3201 inputs data to be transmitted to the client device 31. In the screen transfer system of this embodiment, the input data is a screen update in the server device 32. Details of the screen update will be described later with reference to FIGS.

  The fifth distribution unit 3202 divides the data delivered from the data supply unit 3201 and distributes the divided data to the transmission units 3203A to 103Z. The division information necessary for combining in the client device 31 is added to the divided data. The data division method and division information will be described later with reference to FIG.

  Transmission units 3203A to 3203 perform transmission processing of the divided data. The input data is converted into a format that can be transmitted on the network, and transmitted to the corresponding receiving unit 201 of the client device 31. TCP / IP is used as the transmission protocol. In this embodiment, each transmission unit 103 is a TCP stream (logical pipe for sending data).

  The transmission rate measuring unit 3204 measures the data transmission rate. Here, the transmission rate is the amount of data transmitted per unit time. The unit of the transmission rate is expressed in bits per second.

  The transmission processing time rate calculation unit 3205 measures the transmission processing time rate of data transmission. The transmission processing time rate is a ratio of time spent for data transmission processing in a specified time interval.

≪ Client device configuration ≫


The client device 31 includes receiving units 3101A to 3101A, a combining unit 3102, and a display unit 3103.

  The receiving units 3101 </ b> A to 3101 receive data from the server device 32 via the network 3.

  The combining unit 3102 combines data using the division information given to the data passed from the receiving unit 201.

  The display unit 3103 displays the combined data.

≪Process flow≫

Next, processing performed by the screen transfer system according to the present embodiment will be described with reference to the drawings as appropriate. The server device 32 and the client device 31 are physically connected via the network 3.

≪ Processing flow (generation of screen update) ≫

When execution of screen transfer is started, the data supply unit 3201 of the server device 32 performs screen update generation processing in accordance with the operating state of the operating system and application. The screen update is information for changing the drawing state of the screen. FIG. 6 shows an example of screen update. The screen update includes area information indicating the position of the area to be updated and image information of the corresponding area. The area information is a numerical value indicating the display position of the image information in the screen area. FIG. 7 is a diagram for explaining the region information.

  For example, as shown in FIG. 7, when the upper left corner of the screen area is (0, 0) and the lower right corner is (Width, Height), the upper left coordinates (Left, Top) of the display position and the lower right coordinates (Right, (Bottom). The image information is bitmap data after updating the area corresponding to the area information (such as RGB three color values in each rectangular pixel). The data supply unit 3201 outputs the screen update to the fifth distribution unit 3202 as data to be transmitted.

  The processing of the fifth distribution unit 3202 will be described with reference to FIG. FIG. 9 is a flowchart showing processing of the fifth distribution unit 3202 of the server device 32 of FIG. When the fifth distribution unit 3202 receives data to be transmitted from the data supply unit 3201, the fifth distribution unit 3202 distributes the data to the plurality of transmission units 3203A to 3203A. First, the data received from the data supply unit 3201 is divided for each prescribed size (eg, 8 kilobytes) (step S1001). Next, division information necessary for combining in the client device 31 is added to each divided data. An example of the division information is shown in FIG. In the example, after the data to be transmitted is divided into four, division information is given to each. The division information is composed of two numerical values: “serial number of data after division” / “total number of data after division”.

  Next, the fifth distribution unit 3202 distributes the divided data to the transmission units 3203A-Z. The fifth distribution unit 3202 determines a distribution destination to which transmission unit 103 is used to perform transmission processing on the divided data. The fifth distribution unit 3202 stores the value of the number of TCP streams to be used as a parameter, and distributes the number of transmission units 103 equal to this value. The initial value of the number of TCP streams is arbitrary (for example, 1). Thereafter, the number of TCP streams is changed by the stream number determination unit 3206. The method of determining the distribution destination is arbitrary. For example, a method of assigning in order from the transmission unit 3203A may be used. The TCP stream state value (congestion window size or the like) corresponding to each transmission unit 103 may be checked, and the transmission unit 103 having a large value may be preferentially assigned.

  Next, the fifth distribution unit 3202 once records the current time (e.g., elapsed time since the server device 32 is activated) as the transmission processing start time before transferring the data to the transmission unit 103 (step S1203). In step S <b> 1002), the divided data is transferred to each transmission unit 103 according to the above-described assignment. Each transmitting unit 103 converts the received data into a format that can be transmitted on the network, and transmits the data to the corresponding receiving unit 201 of the client device 31 (step S1003). When the transmission process is completed, the transmission unit 103 notifies the fifth distribution unit 3202 respectively. Next, when the fifth distribution unit 3202 confirms that transmission of all data to be transmitted is completed, the fifth distribution unit 3202 checks the current time again and records it as the transmission processing end time (step S1004). The transmission processing time required for the transmission processing is calculated from the difference from the transmission processing start time, and this is notified to the transmission processing time rate calculation unit 3205. The transmission processing time rate calculation unit 3205 has a storage area for storing the accumulated value of the transmission processing time, and adds the notified value to the stored value. Thereafter, the storage value is updated each time a notification is received until a request for acquiring a transmission processing time rate is received from the number-of-streams determination unit 3206 described later. Furthermore, the fifth distribution unit 3202 notifies the transmission rate measurement unit 3204 of the data size that has been transmitted (step S1006). The transmission rate measuring unit 3204 has a storage area for storing the accumulated value of the data size, and adds the notified value to the stored value. Thereafter, the storage value is updated each time a notification is received until a transmission rate acquisition request is received from the stream number determination unit 3206.

  In addition, although the timing which the transmission part 103 notifies of transmission completion can consider various methods according to mounting, this embodiment is not limited to any of them. For example, the transmission unit 103 may notify the completion of transmission at the timing when the transmission unit 103 finishes sending data to the network 3 to the reception unit 201. For example, transmission completion may be notified at the timing when an acknowledgment (ACK) for the data is received from the receiving unit 201. For example, the transmission completion is notified at the timing when copying to the transmission buffer of the transmission unit 103 (a buffer for temporarily holding data waiting to be transmitted to the network 3 or ACK waiting for post-transmission data) is completed. Also good.

  In the present embodiment, the time required from when the fifth distribution unit 3202 receives the data to be transmitted from the data supply unit 3201 to the completion of transmission of all the data is defined as the transmission processing time. Not necessary. For example, the transmission processing time may be as follows. The fifth distribution unit 3202 has a buffer for temporarily holding data waiting to be transmitted. When data to be transmitted is passed from the data supply unit 3201, it should be transmitted if the buffer is empty. Copy data into the buffer. If the buffer is not empty, wait until it is empty before copying. The transmission processing end time is defined as the timing when the copying to the buffer is completed, and the transmission processing time is calculated therefrom.

  As described above, the data passed to each of the transmission units 3203A to Z reaches the corresponding reception units 3101A to 3101 through the network 3, respectively. The reached data is passed to the combining unit 3102.

  When the combining unit 3102 receives the data, the combining unit 3102 combines the data using the assigned division information. When all the data after the division described in the division information is received, they are combined, and the original data (screen update generated by the data supply unit 3201 of the server device 32) is reconstructed. The original data is passed to the display unit 3103. The display unit 3103 has a frame buffer (recording area corresponding to the screen area), and overwrites and updates the information corresponding to the area information included in the screen update with the screen information. The latest state of the frame buffer is visually presented to the user.

  The flow of processing from when a screen update is generated in the server device 32 until it is transmitted to the client device 31 and displayed is described above.

≪ Processing flow (deciding the number of streams) ≫

Next, the processing flow of the stream number determination unit 3206 will be described. The stream number determination unit 3206 determines the next number of streams at an arbitrary timing (for example, every 5 seconds) by the procedure described below. The determined value is notified to the fifth distribution unit 3202, and the number of TCP streams (transmission unit 103) used by the first distribution unit 102 during transmission is changed.

  First, the stream number determination unit 3206 issues a transmission rate acquisition request to the transmission rate measurement unit 3204. The transmission rate measurement unit 3204 stores a cumulative value of the data size. Upon receiving the acquisition request, the transmission rate measurement unit 3204 calculates an elapsed time from the previous acquisition, and removes the cumulative value of the data size. To calculate the transmission rate. The transmission rate measuring unit 3204 outputs the calculated value to the stream number determining unit 3206, and then resets the accumulated value to zero.

  Next, the stream number determination unit 3206 issues a transmission processing time rate acquisition request to the transmission processing time rate calculation unit 3205. The transmission processing time rate calculation unit 3205 stores a cumulative value of the transmission processing time, and the transmission processing time rate calculation unit 3205 calculates the transmission processing time rate when receiving the acquisition request. The transmission processing time rate is a ratio of time spent for data transmission processing in a certain time interval. First, the elapsed time from the previous acquisition is calculated, and the transmission processing time rate is calculated by dividing the accumulated value of the transmission processing time. The transmission processing time rate calculation unit 3205 outputs the calculated value to the stream number determination unit 3206 and then resets the accumulated value to zero.

  Also, the stream number determination unit 3206 obtains the value of the number of currently used TCP streams from the fifth distribution unit 3202.

  As described above, the stream number determination unit 3206 obtains each value of the number of TCP streams, the transmission rate, and the transmission processing time rate. Hereinafter, the number of TCP streams is described as N, the transmission rate at that time as S, and the transmission processing time rate as R. The number-of-streams determination unit 3206 determines the value of the number of next TCP streams Nnext to be used based on the values of N, S, and R.

≪ First example of decision processing ≫

A first example of the process for determining the number of streams will be described with reference to FIG. First, the stream number determination unit 3206 determines whether or not the transmission processing time rate R exceeds a predetermined threshold Rt (for example, 0.9) (step S1101). As described above, the transmission processing time rate R is an index indicating the ratio of the time spent for the data transmission processing in the processing time of the server device 32. Therefore, when the value of R is large, it can be considered that much of the processing time of the server device 32 is spent on the transmission processing. This means that the transmission unit 103 (TCP stream) cannot transmit data at a sufficient rate, and the transmission rate may be improved by increasing the number of TCP streams and increasing the degree of parallelism. It means that there is. On the other hand, when the value of R is small, it can be considered that the time spent for the transmission process in the processing time of the server device 32 is relatively small. This means that the rate of data supplied from the data supply unit 3201 (data input rate) is smaller than the data transmission rate achievable by the transmission unit 103. At this time, when the value of the number of TCP streams is further increased, an improvement in the transmission rate cannot be expected. Therefore, in this determination process, when the transmission processing time rate R is lower than the threshold value Rt, the transmission rate cannot be improved when the value of the next TCP stream number Nnext is changed from the current TCP stream number N. The policy is to use the same value as the current situation.

  When R is less than Rt, Nnext is determined to use the same value as N (step S1107), and the determination process ends. If it exceeds, the values of N and S are stored as follows (step S1102). The stream number determination unit 3206 stores the table illustrated in FIG. 11 in the storage unit 32061. FIG. 11 is a diagram illustrating an example of a table held by the storage unit 32061 of the stream number determination unit 3206 of the server device 32 of FIG. Although the storage unit 32061 is described as being in the stream number determination unit 3206, it may be outside the stream number determination unit 3206.

  In this table, pairs of N and S values are stored in ascending order of N. Furthermore, the ordinal number is stored. One set of ordinal number i, TCP stream number N, and transmission rate S is called an entry. The number-of-streams determination unit 3206 first checks whether there is an entry in the table that is equal to the acquired value of N, and if it exists, overwrites and updates the S value of that entry with the acquired value of S. . If it does not exist, a new entry consisting of the acquired N and S values is created and added to the table. Sort the added table with respect to N and renumber the ordinal numbers.

  Using the table updated as described above, the stream number determination unit 3206 determines Nnext according to the following policy. Usually, if the number of TCP streams is increased, the transmission rate is improved. However, when the transmission rate reaches the upper limit of the network bandwidth, the transmission rate does not improve even if it is increased further. Therefore, if the value of the transmission rate S in the table shows a monotonically increasing tendency with respect to N, the TCP stream number Nnext to be used next is selected to be larger than the number of streams stored in the table. If it does not show a monotonous increase and the increase of S reaches a peak at a certain N or more, there is no effect when the value of N is further increased. In this case, the value of N that reaches the peak is selected as Nnext.

  Specifically, the following procedure is performed. First, 1 is selected as the ordinal number i (step S1103), and the next loop processing is performed. The number of entries in the table (the maximum value of the ordinal number i) is set to imax, and if i is equal to imax, the loop is exited (step S1104). The difference between the transmission rate of the entry with ordinal number i (referred to as S [i]) and the transmission rate of the entry with ordinal number i + 1 (referred to as S [i + 1]) is compared with the prescribed threshold value St (step S1105). The threshold value St may be arbitrary. For example, the number of TCP streams N [i] of the entry with the ordinal number i at that time and the number of TCP streams N [i + 1] of the entry with the ordinal number i + 1 are used, and St = (N [i + 1 ] −N [i]) × 4 Mbps. If the difference exceeds St, the value of i is incremented by 1 (step S1106) and the loop processing is continued. If it does not exceed St, it can be determined that the transmission rate reaches the peak at the number of TCP streams of the ordinal number i + 1 at that time (referred to as N [i + 1]), so it is effective to increase the number of TCP streams beyond this. You can expect no. Therefore, the next TCP stream number Nnext is set to an intermediate value between the number of TCP streams of the entry of the ordinal number i (referred to as N [i]) and N [i + 1] (step S1109). On the other hand, if the difference between S [i + 1] and S [i] exceeds the threshold value St for all i, it can be considered that the transmission rate monotonically increases with respect to N. The value is further increased by 1 from the maximum number of TCP streams N [imax] (step S1108).

  An operation example is shown. Now, it is assumed that the value of the transmission processing time rate R exceeds the threshold value Rt and the update of the table entry is completed. Assume that the table at that time is in the state shown in FIG. Furthermore, the transmission rate difference threshold St is assumed to be (N [i + 1] −N [i]) × 4 Mbps. First, the difference between S [1] and S [2] and the magnitude of St are compared. Since N [1] = 1, N [2] = 2, S [1] = 5 Mbps, and S [2] = 10 Mbps, S [2] −S [1] = 10−5 = 5 Mbps, St = ( 2-1) × 4 = 4 Mbps, and S [i + 1] −S [i]> St in step S1105? This determination is YES. Next, the difference between S [2] and S [3] and St is compared. Since N [2] = 2, N [3] = 4, S [2] = 10 Mbps, and S [3] = 19 Mbps, S [3] −S [2] = 19−10 = 9 Mbps, St = ( 4-2) × 4 = 8 Mbps, and the determination in step S1105 is YES again. Next, the difference between S [3] and S [4] and the magnitude of St are compared. Since N [3] = 4, N [4] = 6, S [3] = 19 Mbps, and S [4] = 20 Mbps, S [4] −S [3] = 20−19 = 1 Mbps, St = ( 6-4) × 4 = 8 Mbps, and the determination in step S1105 is NO. The process proceeds to step S1109. Since the value of i at this time is 3, the value of Nnext is determined as (N [3] + N [4]) / 2 = (4 + 6) / 2 = 5.

  In this way, by using the value of the next TCP stream number N using the value of the transmission rate S in addition to the value of the transmission processing time rate R, the transmission rate is increased even if the value of N is increased by a certain value or more. Even in a situation where there is no improvement effect, it is determined appropriately, and an increase in the number of unnecessary TCP streams is avoided.

  In the first example, the method for determining Nnext is switched depending on whether or not the value of the transmission rate S shows a monotonically increasing tendency with respect to N. However, more detailed switching may be performed. For example, if the result of step S1105 is NO, and the value of the ordinal i is 1, a selection may be made to make the value of Nnext smaller than N [1].

  In the table, a process of deleting an entry that has passed a predetermined time after storage may be added. As a result, it is possible to continue to select an appropriate number of TCP streams while adapting to the environment of the network 3 that is different for each installation destination and the situation of the network 3 that changes every moment.

  The first example of the determination process has been described above.

≪ Second example of decision processing ≫

Next, a second example of the determination process will be described with reference to FIG. FIG. 12 is a diagram illustrating a flowchart of a second example of the process for determining the number of streams.

  The storage unit 32061 of the stream number determination unit 3206 has a table for holding the acquired values of N, S, and R. An example of the table is shown in FIG. FIG. 13 is a diagram illustrating a second example of a table held by the storage unit 32061 of the stream number determination unit 3206 of the server apparatus 32 of FIG. Although the storage unit 32061 is described as being in the stream number determination unit 3206, it may be outside the stream number determination unit 3206.

  Unlike the first example, in the second example, the value of R is stored in addition to N and S (step S1201). First, the number-of-streams determination unit 3206 checks whether there is an entry in the table that is equal to the acquired value of N. Overwrite with. In the table, in addition to N, S, and R, values obtained by dividing S by R are stored together. If it does not exist, a new entry consisting of the acquired values of N, S, and R is created and added to the table. Sort the added table with respect to N and renumber the ordinal numbers.

  The transmission processing time rate R is the ratio of the time spent for data transmission processing in the processing time of the server device 32. Since the transmission rate at this time is given by S, the value of S / R can be regarded as an approximate value of the upper limit of the transmission rate that can be achieved by the transmission unit 103. Therefore, the value of the next used TCP stream number Nnext is determined according to whether or not the S / R value monotonously increases with respect to N.

  The subsequent determination processing is the same as the procedure in which step S1103 and subsequent steps in the first example are read as S → S / R. In order from 1 as the ordinal number i (steps S1202 to S1205), the difference between the S [i] / R [i] of the entry of the ordinal number i and S [i + 1] / R [i + 1] of the entry of the ordinal number i + 1, and the prescribed threshold value (S / R) The magnitude is compared with t. If the difference falls below the threshold value (S / R) t, the value of Nnext is determined as (N [i] + N [i + 1]) / 2 using i at that time. If the difference is greater than (S / R) t for all i less than imax, S / R is regarded as monotonically increasing with respect to N, and the value of Nnext is set to a value larger than N [imax]. An operation example is omitted.

≪ Third example of decision processing ≫

A third example of the determination process will be described with reference to FIG. FIG. 14 is a diagram illustrating a flowchart of a third example of the process for determining the number of streams.

  The stream number determination unit 3206 determines whether or not the transmission processing time rate R exceeds a predetermined threshold Rt (for example, 0.9) (step S1301). When the value of R is smaller than the threshold (step S1302), the same N value as the current value is used as the value of Nnext based on the same determination as in the first example of the determination process. On the other hand, when the threshold value is exceeded (step S1303), since most of the processing time of the server device 32 is spent for transmission processing, it is possible to improve the transmission rate by increasing the number of TCP streams. Therefore, N + 1 larger than the current value is used as the value of Nnext. An operation example is omitted.

  As described above, according to the present embodiment, even when the input rate of data to be transmitted varies with time, an appropriate TCP stream that secures a transmission rate and does not cause unnecessary processing load. The number can be determined.

  The server device 32 can also be realized by using, for example, a general-purpose computer device as basic hardware. That is, the data supply unit 3201, the fifth distribution unit 3202, the plurality of transmission units 3203A to 3203Z, the transmission rate measurement unit 3204, the transmission processing time rate calculation unit 3205, and the stream number determination unit 3206 This can be realized by causing a processor mounted on a computer apparatus to execute a program. At this time, the server device 32 may be realized by installing the above-described program in a computer device in advance, or may be stored in a storage medium such as a CD-ROM or distributed through the network. Thus, this program may be realized by appropriately installing it in a computer device.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Client device 31 ... Server device, 3 ... Network, 100 ... Data supply part, 101 ... Establishment instruction | indication part, 102 ... 1st distribution part, 103 ... 1st Transmission unit 104 ... second transmission unit 105 ... establishment unit 106 ... establishment unit 107 ... second distribution unit 200 ... first reception unit 201 ... Second receiving unit, 202 ... standby unit, 203 ... standby unit, 204 ... first collection unit, 205 ... second collection unit, 206 ... data input / output unit, DESCRIPTION OF SYMBOLS 110 ... Data supply part, 111 ... Establishment instruction | indication part, 112 ... 3rd collection part, 113 ... 1st receiving part, 114 ... 2nd receiving part, 115 ... Establishment , 116 ... establishment unit, 117 ... fourth collection unit, 210 ... first transmission unit, 211 ... second transmission unit 212 ... Standby unit, 213 ... Standby unit, 214 ... Third distribution unit, 215 ... Standby unit, 216 ... Fourth distribution unit, 217 ... Data input / output unit , 31 ... Client device, 32 ... Server device, 3101A-Z ... Receiving unit, 3102 ... Coupling unit, 3103 ... Display unit, 3201 ... Data supply unit, 3202 ... 5th distribution part, 3203A-Z ... transmission part, 3204 ... transmission rate measurement part, 3205 ... transmission processing time measurement part, 3206 ... stream number determination part, 32061 ... storage part.

Claims (24)

A device for communicating with a first communication device connected via a network,
A first communication unit that performs processing for establishing a first connection, and performs communication by a first transmission method when the first connection is established with the first communication device;
A second communication unit that performs processing for establishing a second connection, and performs communication using the second transmission method when the second connection is established with the first communication device;
The timing at which the first communication unit performs processing for establishing the first connection and the timing at which the second communication unit performs processing for establishing the second connection overlap. And instructing the first communication unit to perform processing for establishing the first connection, and establishing the second connection to the second communication unit. An instruction unit for issuing a second instruction so as to perform processing for
A distribution unit;
When the first communication unit completes the process for establishing the first connection, the first communication unit notifies the distribution unit of a first message;
The second communication unit, when completing the process for establishing the second connection, notifies the distribution unit of a second message,
The distribution unit distributes the transmission data to either the first communication unit or the second communication unit that first completed establishment of all connections used for communication, and the first communication. When the first unit completes the process for establishing the first connection, the transmission data is distributed to the first communication unit, and the second communication unit establishes the second connection. A communication apparatus that switches a distribution destination of the transmission data from the first communication unit to the second communication unit after completing the processing for performing the processing.   The first connection is composed of a single stream, the second connection is composed of a plurality of streams, and the first transmission method is a transmission method for performing communication using a single stream, The communication apparatus according to claim 1, wherein the second transmission method is a transmission method for performing communication using a plurality of streams. A system comprising a first communication device and a second communication device connected via a network,
The first communication device is:
A first communication unit that performs processing for establishing a first connection, and performs communication by a first transmission method when the first connection is established with the first communication device;
A second communication unit that performs processing for establishing a second connection, and performs communication using the second transmission method when the second connection is established with the first communication device;
The timing at which the first communication unit performs processing for establishing the first connection overlaps with the timing at which the second communication unit performs processing for establishing the second connection. And instructing the first communication unit to perform processing for establishing the first connection, and establishing the second connection to the second communication unit. An instruction unit for issuing a second instruction so as to perform processing for
A distribution unit;
When the first communication unit completes the process for establishing the first connection, the first communication unit notifies the distribution unit of a first message;
When the second communication unit completes the process for establishing the second connection, the second communication unit notifies the distribution unit of a second message,
The distribution unit distributes the transmission data to either the first communication unit or the second communication unit that first completed establishment of all connections used for communication, and the first communication. When the unit first completes the process for establishing the first connection, the transmission data is distributed to the first communication unit, and the second communication unit establishes the second connection. After completing the process for the transmission, the distribution destination of the transmission data is switched from the first communication unit to the second communication unit,
The second communication device is:
Performs processing for establishing a first connection, and communicates with the first communication unit of the first communication device using the first transmission method when the first connection is established. A third communication unit;
A process for establishing a second connection and performing communication in the second communication method when the second connection is established with the second communication unit of the first communication device. The communication department of
A collection unit that receives the transmission data received by the third communication unit and the second communication unit from the communication unit and the second communication unit, and outputs the received transmission data; ,
The collection unit receives all the transmissions received from the third communication unit when the distribution unit switches the distribution destination of the transmission data from the first communication unit to the second communication unit. After outputting data, the system starts outputting the transmission data received from the fourth communication unit. The first communication device transmits the transmission data distributed to the first communication unit by the distribution unit until the transmission destination of the transmission data is switched from the first communication unit to the second communication unit. Informing the second communication device of the data size of the data;
The said collection part judges that all the said transmission data received from the said 3rd communication part were output, when the said transmission data of the notified said data size was output. System.   The first connection is composed of a single stream, the second connection is composed of a plurality of streams, and the first transmission method is a transmission method for performing communication using a single stream, 4. The system according to claim 3, wherein the second transmission method is a transmission method in which communication is performed using a plurality of streams. A device that communicates with a first communication device connected via a network,
A plurality of transmitters;
A plurality of first division data generated by dividing the first data, and a distribution unit that distributes the plurality of first division data to the plurality of transmission units;
A calculation unit that calculates a transmission processing time rate that is a ratio of a transmission processing time required for the plurality of transmission units to transmit the first data to the first communication device in an arbitrary period; ,
The distribution unit includes a determination unit that determines, based on the transmission processing time ratio, a number of the plurality of second divided data generated by dividing the second data to be distributed to the number of the transmission units. ,
The distribution unit distributes the plurality of second divided data to the number of transmission units determined by the determination unit.   The determining unit distributes the second divided data to the same number of transmitting units as the number of distributions of the first divided data by the distributing unit when the transmission processing time rate is smaller than a predetermined threshold. The communication device according to claim 6, wherein the communication device is determined.   The determining unit distributes the second divided data to a larger number of transmitting units than the number obtained by dividing the first divided data when the transmission processing time rate is larger than a predetermined threshold. The communication device according to claim 7, wherein the communication device is determined. A transmission rate measuring unit that measures a transmission rate that is an amount of data transmitted by the plurality of transmitting units in a certain period of time;
9. The communication apparatus according to claim 8, wherein the determination unit determines how many transmission units the second divided data is distributed based on the transmission processing time rate and the transmission rate. In the past, the distribution unit further includes a storage unit that stores a correspondence relationship between the number of the transmission units to which the data has been distributed and a transmission rate that is the amount of data transmitted by the number of transmission units in a certain period of time.
The determination unit transmits the number of transmission units to which the distribution unit has distributed the first divided data and the first data measured by the measurement unit when the transmission processing time rate is greater than a predetermined threshold. And updating the correspondence relationship stored in the storage unit based on the correspondence relationship with the transmission rates of the plurality of transmission units when the distribution unit is configured to update the second division. 10. The communication apparatus according to claim 9, wherein the number of transmission units to which data is distributed is determined.   In the correspondence relationship after the update, the determination unit determines whether the distribution unit determines the second transmission rate based on the increase in the transmission rate with respect to the increase in the number of the transmission units to which the distribution unit has distributed data. The communication apparatus according to claim 10, wherein the number of transmission units to which the divided data is distributed is determined.   In the updated correspondence relationship, the determination unit has a case in which all correspondence relationships stored in the storage unit are larger in magnitude of the increase in the transmission rate with respect to the increase in the number of the transmission units to which data is distributed. The communication device according to claim 11, wherein the distribution unit distributes the second divided data with a larger number of transmission units than the number stored in the storage unit.   In the correspondence after the update, when the distribution unit has a correspondence in which the magnitude of the increase in the transmission rate with respect to the increase in the number of the transmission units to which the data has been distributed is less than a predetermined value, 13. The distribution unit determines how many transmission units the second divided data is distributed based on the number before and after the correspondence that is less than the predetermined value. Communication equipment.   The determining unit, in the updated correspondence relationship, when the distribution unit has a correspondence relationship in which the transmission rate does not change with respect to an increase in the number of the transmission units to which data has been distributed, 14. The communication apparatus according to claim 13, wherein the distribution unit determines how many transmission units the second divided data is distributed based on the number of front and rear.   In the updated correspondence relationship, the determination unit has a correspondence relationship in which the transmission unit decreases when the transmission rate decreases with respect to an increase in the number of the transmission units to which the data has been distributed. The communication device according to claim 14, wherein the distribution unit determines how many transmission units the second divided data is distributed based on the number of front and rear. And a transmission rate measuring unit that measures a transmission rate indicating the amount of the first data transmitted by the plurality of transmitting units in a certain time period,
The said determination part determines how many transmission parts distribute the said 2nd division | segmentation data based on the value which divided the said transmission rate by the said transmission processing time rate. Communication equipment. In the past, the distribution unit stores the correspondence between the number of the transmission units that have distributed data and the value obtained by dividing the transmission rate when the data is transmitted using the number of transmission units by the transmission processing time rate. A storage unit;
The determination unit determines the number of transmission units to which the distribution unit has distributed the first data and the transmission rates of the plurality of transmission units when transmitting the first data measured by the measurement unit. Based on the correspondence relationship with the value divided by the number, the correspondence relationship stored in the storage unit is updated, and on the basis of the updated correspondence relationship, the distribution unit converts the second divided data into the number of transmission units. The communication device according to claim 16, wherein it is determined whether or not to distribute the data.   The determination unit, based on the correspondence relationship with the value obtained by dividing the transmission rate by the transmission processing time rate with respect to an increase in the number of the transmission units to which the distribution unit has distributed data in the correspondence relationship after the update. 18. The communication apparatus according to claim 17, wherein the unit determines how many transmission units the second divided data is distributed to.   In the correspondence relationship after the update, the determination unit is configured such that an increase in a value obtained by dividing the transmission rate by a transmission processing time rate with respect to an increase in the number of the transmission units to which the distribution unit has distributed data is greater than a predetermined value. 19. The communication apparatus according to claim 18, wherein when the distribution unit is larger, the distribution unit sets the number of transmission units to distribute the second divided data to a number larger than the number stored in the storage unit.   In the correspondence relationship after the update, the determination unit is less than a predetermined value in an increase in a value obtained by dividing the transmission rate by a transmission processing time rate with respect to an increase in the number of the transmission units to which the distribution unit has distributed data. When there is a corresponding relationship, the distribution unit determines how many transmission units the second divided data is distributed based on the number of correspondences that are less than the predetermined value. The communication device according to claim 19.   The determination unit has a correspondence relationship in which the value obtained by dividing the transmission rate by the transmission processing time rate does not change with respect to an increase in the number of the transmission units to which the distribution unit has distributed data in the correspondence relationship after the update. In this case, the distribution unit determines how many transmission units the second divided data is distributed based on the numbers before and after the unchanged correspondence. Communication equipment.   The determination unit has a correspondence relationship in which the value obtained by dividing the transmission rate by the transmission processing time rate with respect to an increase in the number of the transmission units to which the distribution unit has distributed data is reduced in the correspondence relationship after the update. 20. The communication according to claim 19, wherein, based on the numbers before and after the decreasing correspondence, the distribution unit determines how many transmission units the second divided data is distributed to. apparatus. A program for controlling a device that communicates with a first communication device connected via a network,
A first communication function for performing a process for establishing a first connection and performing communication in a first transmission method when the first connection with the first communication device is established;
A second communication function for performing a process for establishing a second connection and performing communication in a second transmission method when the second connection is established with the first communication device;
The timing at which the first communication function performs processing for establishing the first connection and the timing at which the second communication function performs processing for establishing the second connection overlap. Instructing the first communication function to perform the process for establishing the first connection, and establishing the second connection for the second communication function An instruction function for issuing a second instruction to perform processing for
A distribution function,
When the first communication function completes the process for establishing the first connection, the first communication function notifies the distribution function of a first message;
When the second communication function completes the process for establishing the second connection, the second communication function notifies the distribution function of a second message;
The distribution function distributes the transmission data to either the first communication function or the second communication function that has first completed establishment of all connections used for communication, and the first communication. When the function first completes the process for establishing the first connection, the transmission data is distributed to the first communication function, and the second communication function establishes the second connection. A program for switching the distribution destination of the transmission data from the first communication function to the second communication function after completion of the processing for performing the processing. A program for controlling a device that communicates with a first communication device connected via a network,
Multiple sending functions,
A distribution function for dividing the first data to generate a plurality of first divided data and distributing the plurality of first divided data to the plurality of transmission functions;
A calculation function in which the plurality of transmission functions calculate a transmission processing time ratio that is a ratio of a transmission processing time required to transmit the first data to the first communication device in the first period; ,
Based on the transmission processing time rate, the distribution function distributes a plurality of second divided data generated by dividing the second data to the number of transmission functions among the plurality of transmission functions. With a decision function to decide,
The distribution function distributes the plurality of second divided data to the number of transmission functions determined by the determination function.

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