JP2005192102A - Transmission apparatus, relay apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable performing data communication, in a preferred manner according to the data quantity of data to be transmitted to a communication terminal, without causing the data quantity to be transmitted/received to/from the communication terminal to be increased. <P>SOLUTION: A transmission apparatus performs window control to transmit data, when transmitting the transmission data via a communication network. This apparatus is allowed to specify the mode of window control to be performed on the basis of the data quantity of transmission data to be transmitted to the communication terminal, and to transmit the transmission data to the communication terminal, while performing window control in a specified mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for performing data communication with a communication terminal in a suitable communication mode.

  In recent years, with the widespread use of mobile phones having a browser function, it has become common to access content servers on the Internet and browse content using such mobile phones. Among this type of mobile phone, third-generation mobile phones such as W-CDMA (Wideband Code Division Multiple Access) and cdma2000 (Code Division Multiple Access 2000), and PDC (Personal Digital Cellular) mobile phone There are two-generation mobile phones, and the former can perform high-speed data communication compared to the latter. In such a situation where communication terminals having different communication speeds are used together, if the data is always transmitted at a communication speed suitable for one of the terminals, the other communication terminal efficiently performs data communication. There is a problem that cannot be done. As an example of a technique for solving such a problem, a technique disclosed in Patent Document 1 can be cited.

More specifically, in the technique disclosed in Patent Document 1, it is possible to perform communication in a suitable mode by causing a communication terminal that receives data transmitted from a transmission apparatus to perform an operation as described below. Realized. First, after transmitting a communication message (Syn packet) requesting the start of communication to the transmitting device, a response message (SynAck packet) to which additional data having the same data size as the data is added is transmitted. The communication terminal is caused to measure the round trip time until it is transmitted from the device. Based on the round trip time and the amount of additional data measured in this way, the communication terminal estimates the communication band of the communication path with the transmission device, and the communication such as the browser based on the estimation result. Set the operation mode of the application. In addition, the communication terminal obtains transfer time information between the routers from each router existing on the communication path, and relay devices at both ends of the link having a large difference between the uplink transfer rate and the downlink transfer rate. Is notified of the operation mode and the relay apparatus is set with the optimum communication parameters for the operation mode.
JP 2000-278320 A

  However, in the technique disclosed in Patent Document 1, additional data having the same data amount as the data to be transmitted to the communication terminal is added to the SynACK packet transmitted from the transmission device to the communication terminal. This increases the amount of data transmitted and received between the device and the communication terminal. Thus, if the amount of data transmitted and received between the transmission device and the communication terminal is increased, an excessive load is applied to the communication network and the relay device that relay communication between the two. Absent.

  The present invention has been made in view of the above problems, and in a preferred mode according to the amount of data transmitted to the communication terminal without increasing the amount of data transmitted to and received from the communication terminal. The object is to provide a technology that enables data communication.

  In order to solve the above-described problems, the present invention provides storage means stored for each data amount of data transmitted by a control parameter indicating a window control mode, and data of transmission data transmitted to a communication terminal via a communication network. A specifying means for specifying a control parameter indicating a mode of window control performed when transmitting the transmission data to the communication terminal based on the specifying result and the storage content of the storage means, There is provided a transmission device having transmission means for transmitting the transmission data to the communication terminal while performing window control in a mode indicated by the control parameter specified by the means.

  In order to solve the above-mentioned problem, the present invention transmits a computer apparatus to a communication terminal via a communication network and a storage means for storing a control parameter indicating a window control mode for each data amount to be transmitted. A specification for specifying a control parameter indicating a mode of window control to be performed when transmitting the transmission data to the communication terminal based on a specification result and a storage content of the storage unit, while specifying a data amount of transmission data to be transmitted And a program for functioning as transmission means for transmitting the transmission data to the communication terminal while performing window control indicated by the control parameter specified by the specifying means.

  According to such a transmission apparatus and program, the control parameter indicating the mode of window control to be performed when transmitting the data is specified according to the data amount of the data to be transmitted to the communication terminal.

  Further, in order to solve the above-mentioned problems, the present invention provides a storage means storing each control data indicating a window control mode for each data amount to be transferred and a transmission device to a communication terminal via a communication network. A receiving means for receiving the transmission data, and a data amount of the transmission data received by the receiving means, while transferring the transmission data to the communication terminal based on the identification result and the storage contents of the storage means Specifying means for specifying a control parameter indicating a mode of window control to be performed, and transfer means for transferring the transmission data to the communication terminal while performing window control in a mode indicated by the control parameter specified by the specifying means A relay device is provided.

  In order to solve the above-mentioned problem, the present invention communicates from a transmitting device via a communication network with a storage means for storing a computer device for each data amount of data for transferring control parameters indicating a window control mode. A receiving means for receiving transmission data to be transmitted to the terminal; and a data amount of the transmission data received by the receiving means, while specifying the transmission data on the basis of the specifying result and the storage content of the storage means A specifying means for specifying a control parameter indicating a mode of window control to be performed when transferring to the communication terminal, and a window control in a mode indicated by the control parameter specified by the specifying means, while transmitting the transmission data to the communication terminal Provided is a program that functions as transfer means for transferring.

  According to such a relay apparatus and program, the transmission apparatus that transmits the transmission data to the communication terminal is notified of the control parameter indicating the window control mode to be performed according to the data amount of the transmission data.

  According to the present invention, it is possible to perform data communication in a suitable manner according to the data amount of data to be transmitted to the communication terminal without increasing the amount of data transmitted to and received from the communication terminal. There is an effect.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[A: First Embodiment]
(A-1: Configuration of communication system)
FIG. 1 is a diagram illustrating a configuration example of a communication system according to the first embodiment of the present invention. A communication terminal 10 in FIG. 1 is a W-CDMA mobile phone and has the above-described browser function. In the present embodiment, the case where the communication terminal 10 is a W-CDMA mobile phone having a browser function will be described. However, a PDC mobile phone having a browser function or a PHS (Personal Handyphone System: registered trademark) is described. ), PDA (Personal Digital Assistant), mobile personal computer (hereinafter referred to as PC), or the like. Moreover, although one communication terminal is illustrated in FIG. 1, actually there are a plurality of communication terminals.

  A wireless communication network 20 in FIG. 1 is a W-CDMA wireless communication network for accommodating a W-CDMA mobile phone located in the service area of its own network and providing a wireless communication service. is there.

  The relay device 30 in FIG. 1 is a gateway device, for example, and is connected to the wireless communication network 20 and the Internet 40. The relay device 30 has a function of mutually converting a communication protocol in the wireless communication network 20 and a communication protocol in the Internet 40, and is connected to the communication terminal 10 accommodated in the wireless communication network 20 and the Internet 40. This is for mediating communication with the transmitting device 50.

  The transmission device 50 stores content (for example, document data described in HTML) that is transmission data to be distributed via the Internet 40, and the content is stored in a predetermined communication protocol such as TCP (Transmission Control Protocol). Therefore, transmission can be performed while performing window control. Here, the window control is to gradually increase the amount of data to be transmitted so that congestion does not occur in the communication path with the communication partner terminal. Specifically, when the transmission device 50 receives a communication message requesting transmission of the content (hereinafter referred to as a content transmission request), the transmission device 50 first divides the content into predetermined data size units, and then divides the divided content. And a data block (hereinafter referred to as a segment) including a sequence number indicating the division position in bytes. Then, the transmitting device 50 transmits a predetermined number (hereinafter referred to as a congestion window size) in order from the smallest sequence number included. Thereafter, each time the transmission device 50 receives a communication message (hereinafter referred to as an acknowledgment) in which the sequence number of the segment to be transmitted next is written, the transmission window size is set to a predetermined algorithm (for example, a slow start algorithm). Therefore, subsequent segments are transmitted while increasing. The slow start algorithm is an algorithm that increases the congestion window size exponentially every time the confirmation response is received. Further, the number of segments (hereinafter referred to as transmission window size) transmitted by the transmission device 50 in one transmission operation, whichever is smaller between the congestion window size and the advertisement window size written in the confirmation response. In the following, it is assumed that the advertisement window size is a sufficiently large value, and the transmission window size always matches the congestion window size.

  This transmission device 50 is different from the conventional transmission device that transmits the content by performing the window control according to the data amount of the content to be transmitted to the communication terminal 10 that is the transmission source of the content transmission request. The window control is performed by changing the initial value of the congestion window size (hereinafter referred to as the initial window size). Specifically, when the data amount of the content is 50 kilobytes (1 kilobyte = 1024 bytes) or more, the transmitting device 50 sets a value representing three segments in the initial window size, Conversely, when the data amount of the content is less than 50 kilobytes, a value representing 10 segments is set in the initial window size. Due to such a configuration, according to the transmission device 50 according to the present embodiment, transmission of the content is completed with a smaller number of transmission operations for a content with a smaller data amount. In the following, a description will be given focusing on the transmission device 50 that significantly shows the features of the communication system shown in FIG.

(A-2: Configuration of transmitting apparatus 50)
First, the configuration of the transmission device 50 will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of a hardware configuration of the transmission device 50. As shown in FIG. 2, the transmission device 50 includes a control unit 100, a communication interface (hereinafter referred to as “IF”) unit 110, a storage unit 120, and data exchange between these components. And a bus 130 which mediates

  The control unit 100 is, for example, a CPU (Central Processing Unit), and controls each unit of the transmission device 50 by reading and executing software stored in the storage unit 120. The communication IF unit 110 is connected to the Internet 40, receives data sent via the Internet 40, delivers it to the control unit 100, and sends out the data delivered from the control unit 100 to the Internet 40. It is.

  As illustrated in FIG. 2, the storage unit 120 includes a volatile storage unit 120a and a nonvolatile storage unit 120b. The volatile storage unit 120a is, for example, a RAM (Random Access Memory), and is used as a work area by the control unit 100 operating according to software. On the other hand, the non-volatile storage unit 120b is, for example, a hard disk, and stores the above-described content and the control parameter management table shown in FIG. In this control parameter management table, as shown in FIG. 3, the mode of window control to be performed when transmitting the content in association with the data amount of the content to be transmitted to the transmission source of the content transmission request Is stored (in this embodiment, the initial window size). For example, in the control parameter management table illustrated in FIG. 3, when the data amount of content to be transmitted is 50 kilobytes or more, the initial window size is set to “3”, and the data amount of the content is 50 If it is less than kilobytes, it is indicated that the initial window size should be set to “10”. Although details will be described later, this control parameter management table is used to cause the control unit 100 to specify a suitable initial window size according to the data amount of the content to be transmitted.

  In addition to the content and the control parameter management table, the nonvolatile storage unit 120b stores various types of software such as operating system (hereinafter referred to as “OS”) software and segment transmission software. The OS software is used to cause the control unit 100 to implement the OS, and the segment transmission software causes the control unit 100 to perform segment transmission processing that performs the above-described window control and transmits a segment under the control of the OS. Is for. Hereinafter, functions provided to the control unit 100 by executing these software will be described.

  When the transmission device 50 is powered on (not shown), the control unit 100 first reads and executes the OS software from the nonvolatile storage unit 120b. The control unit 100 operating according to the OS software is provided with a function of controlling each unit of the transmission device 50 and a function of reading out and executing other software from the nonvolatile storage unit 120b. Then, the control unit 100 that completes the execution of the OS software and implements the OS immediately reads the segment transmission software from the nonvolatile storage unit 120b and sequentially executes the segment transmission software. The control unit 100 operating according to the segment transmission software is given the following three functions.

  The first function is a reception function in which the communication IF unit 110 receives a content transmission request transmitted via the Internet 40. Second, based on the data amount of the content requested to be transmitted by the content transmission request received by the reception function and the stored content of the control parameter management table, the content is transmitted to the communication terminal that is the transmission source of the content transmission request. This is a specific function for specifying the mode of window control to be performed when transmitting. Third, the content stored in the non-volatile storage unit 120b is divided into predetermined data size units to generate segments, and window control is performed in a manner specified by the specific function. It is a transmission function to transmit. In the present embodiment, the control parameter specified by the specific function represents the initial window size. For this reason, window control is started with an initial window size corresponding to the data amount of content to be transmitted to the communication terminal 10.

  As described above, the hardware configuration of the transmission device 50 is the same as the hardware configuration of a general computer device, and by causing the control unit 100 to execute various software stored in the storage unit 120, Functions unique to the transmitting apparatus according to the invention are added. In the present embodiment, a case has been described in which functions specific to the transmission apparatus according to the present invention are realized using software modules. However, a transmission apparatus using hardware modules having the same functions as these software modules has been described. Of course, 50 may be configured.

(A-3: Operation of transmitting apparatus 50)
Next, of the operations performed by the transmission device 50, only operations that significantly show the features will be described with reference to the drawings. As a premise of the operation example described below, it is assumed that the control unit 100 of the transmission device 50 operates according to the segment transmission software described above and is waiting to receive a content transmission request transmitted from the communication terminal 10. .

  The user of the communication terminal 10 activates the browser function described above by appropriately operating an operator provided in the operation unit (not shown), and acquires the content stored in the transmission device 50. An instruction (for example, input of the URL of the content) can be performed. When such an operation is performed, the communication terminal 10 generates a content transmission request for requesting transmission of the content, and transmits the content transmission request to the transmission device 50.

  The content transmission request transmitted from the communication terminal 10 reaches the transmission device 50 via the wireless communication network 20, the relay device 30, and the Internet 40 in this order. Hereinafter, an operation performed by the control unit 100 of the transmission device 50 when the content transmission request is received will be described with reference to FIG.

  FIG. 4 is a flowchart showing the flow of segment transmission processing performed by the control unit 100 of the transmission device 50 according to the segment transmission software. As shown in FIG. 4, when the control unit 100 receives the content transmission request by the communication IF unit 110 (step SA1), the control unit 100 analyzes the content transmission request and is requested to transmit by the content transmission request. The amount of content data is specified (step SA2). Specifically, the control unit 100 reads the content specified by the URL included in the content transmission request received in step SA1 from the nonvolatile storage unit 120b, expands the content in the volatile storage unit 120a, Calculate and specify the data volume of the expanded content. In the present embodiment, the case has been described in which the data amount of the content is specified by calculating the data amount of the content expanded in the volatile storage unit 120a. However, directory information and the like under the management of the OS Of course, the data amount of the content may be specified with reference to FIG. The directory information is data representing the hierarchical structure of the file system provided in the nonvolatile storage unit 120b, the data amount of the file belonging to each hierarchy, and the like.

  Next, based on the data amount specified in step SA2 and the stored content of the control parameter management table (see FIG. 3), the control unit 100 indicates a control parameter indicating a mode of window control to be performed when transmitting the content. (In this embodiment, the initial window size) is specified (step SA3). Specifically, when the amount of data specified in step SA2 is 50 kilobytes or more, the control unit 100 specifies the initial window size value as “3”, and conversely, is specified in step SA2. If the amount of data is less than 50 kilobytes, the control unit 100 specifies the value of the initial window size as “10”.

  And the control part 100 performs window control in the aspect which the control parameter specified by step SA3 shows, and transmits the said content (step SA4). Specifically, the control unit 100 generates a segment by dividing the content expanded in the volatile storage unit 120a in step SA1 by a predetermined data size, and is specified in step SA3 from the top of the generated segment. A segment for the initial window size indicated by the control parameter is transmitted. Thereafter, each time the control unit 100 receives the confirmation response transmitted from the communication terminal 10, it performs window control such as increasing the congestion window size according to a predetermined algorithm such as slow start, and transmits the content. To do.

  For example, assuming that the predetermined data size is 1 kilobyte and the content has a data amount of 9 kilobytes, the data amount of 10 segments is set as the initial window size value in step SA3. The indicated value (ie, 10 kilobytes) is specified. Since the data amount of the content is 9 kilobytes, this content is divided into nine segments and transmitted (the header data amount included in each segment is ignored). As described above, since the value representing 10 segments is set in the initial window size, all the corresponding segments are transmitted in one transmission operation for the content.

  On the other hand, in the conventional window control, since the default value of the initial window size is 3, when transmitting the content, first, three segments are transmitted and a corresponding confirmation response has been transmitted. In response to this, the remaining six segments are transmitted. That is, in the conventional window control, two transmission operations are performed for the content. Thus, according to this embodiment, when the data amount of content to be transmitted to the communication terminal is less than a predetermined value, it is possible to complete the transmission of the content with a single transmission operation.

  As described above, according to this embodiment, it is possible to set a suitable initial window size according to the data amount of content to be transmitted to the communication terminal 10 and perform window control to transmit the content. become. In addition, in the present embodiment, the content transmission request transmitted from the communication terminal 10 to the transmission device 50 is a general TCP-compliant communication message, and is a special message for performing an operation characteristic of the present invention. Since there is no need to write additional data, the amount of data transmitted and received between the communication terminal 10 and the transmission device 50 is not increased.

[B: Second Embodiment]
Next, a communication system according to a second embodiment of the present invention will be described with reference to the drawings.

(B-1: Configuration of communication system)
FIG. 5 is a diagram illustrating an example of a communication system according to the second embodiment of the present invention. The communication system shown in FIG. 5 differs from the communication system shown in FIG. 1 in that a relay device 230 is provided instead of the relay device 30 and a transmission device 250 is provided instead of the transmission device 50. is there.

  The transmission device 250 is different from the transmission device 50 in that, when a content transmission request is received, the content is transmitted by performing window control in a predetermined mode (for example, a predetermined initial window size). is there. That is, the transmission device 250 is a conventional transmission device that performs window control and transmits content. For this reason, the detailed description about the transmission apparatus 250 is abbreviate | omitted.

  On the other hand, the relay device 230 is different from the relay device 30 when a segment transmitted from the transmission device 250 (that is, a segment in which content to be transmitted to the communication terminal 10 is divided and included) is received. Next, the data size of the content is specified based on the data written in a predetermined area (for example, Content-Length) of the segment, and the window control is performed in a manner according to the specification result, and the segment is It is a point transferred to the communication terminal 10. Hereinafter, the relay device 230 that is characteristic of the second embodiment will be mainly described.

(B-2: Configuration of relay device 230)
FIG. 6 is a diagram illustrating a configuration example of the relay device 230. As shown in FIG. 6, the configuration of the relay device 230 is different from the configuration of the transmission device 50 (see FIG. 2) in that the first communication IF unit 110 a and the first communication IF unit 110 a are replaced with the communication IF unit 110. 2 communication IF unit 110b.

  The first communication IF unit 110 a is connected to the wireless communication network 20, receives data transmitted via the wireless communication network 20, transfers the data to the control unit 100, and wirelessly transmits the data transferred from the control unit 110. This is for transmission to the communication network 20. The second communication IF unit 110b is connected to the Internet 40. The second communication IF unit 110b receives data transmitted via the Internet 40 and delivers the data to the control unit 100, and sends the data delivered from the control unit 100 to the Internet 40. Is for. In the present embodiment, a case will be described in which a communication IF for performing communication via the wireless communication network 20 and a communication IF for performing communication via the Internet 40 are each implemented by separate hardware. However, it goes without saying that it may be implemented by a single piece of hardware having both functions.

  The storage content of the non-volatile storage unit 120b of the relay device 230 is different from the storage content of the non-volatile storage unit 120b of the transmission device 50 only in the following two points. First, the content is not stored in the nonvolatile storage unit 120b of the relay device 230. This is because the relay device 230 is for transferring the content transmitted from the transmission device 250 to the communication terminal 10 and does not need to store the content at all times. Secondly, in place of the segment transmission software described above, relay software for causing the control unit 100 to implement the relay processing shown in the flowchart of FIG. 7 is stored. Hereinafter, functions provided to the control unit 100 by executing various kinds of software stored in the nonvolatile storage unit 120b will be described.

  When the power supply (not shown) of the relay device 230 is turned on, the control unit 100 reads out and executes the OS software described above from the nonvolatile storage unit 120b, and gives the control unit 100 operating according to the OS software. The functions to be performed are the same as those of the transmission device 50 described above. When the execution of the OS software is completed and the OS is realized, the control unit 100 immediately reads the relay software from the nonvolatile storage unit 120b and sequentially executes the relay software. The control unit 100 operating according to this relay software is given the following three functions.

  The first is a receiving function for receiving a segment transmitted via the Internet 40. Second, the data amount of the content is specified based on the data written in the predetermined area (Conten-Length in this embodiment) of the segment received by the reception function, and the specification result and the control parameter This is a specific function for specifying a control parameter indicating a mode of window control to be performed when transmitting the segment based on the stored contents of the management table (see FIG. 3). Thirdly, there is a transfer function for performing window control in a mode indicated by the control parameter specified by the specifying function and transferring the segment to the destination communication terminal 10. As described above, the control parameter stored in the control parameter management table represents the initial window size. For this reason, in this embodiment, the initial window size when transmitting the content is determined by the specific function, window control is performed with the initial window size as an initial value, and the content is transmitted.

  As described above, the hardware configuration of the relay device 230 is the same as the hardware configuration of a general computer device, and the control unit 100 executes various software stored in the storage unit 120, thereby A function specific to the relay apparatus according to the invention is given. In the second embodiment, the case where the above various functions are realized using software modules has been described. However, the relay device 230 is configured using hardware modules having the same functions as the software modules. Of course, it is also good.

(B-3: Operation of relay device 230)
Next, operations performed by the relay device 230 will be described. FIG. 7 is a flowchart showing a flow of relay processing performed by the control unit 100 operating according to the relay software. As illustrated in FIG. 7, when the control unit 100 of the relay device 230 receives the segment by the second communication IF unit 110b (step SB1), the control unit 100 analyzes the segment and transmits the content to be transmitted to the communication terminal 10. The amount of data is specified (step SB2). Specifically, the control unit 100 specifies data written in a predetermined area (Content-Length in the present embodiment) of the segment received in step SB1 as the data amount of the content.

  Next, based on the data amount specified in step SB2 and the stored contents of the control parameter management table (see FIG. 3), the control unit 100 indicates a control parameter indicating the mode of window control to be performed when the content is transferred. (In this embodiment, the initial window size) is specified (step SB3). Specifically, when the amount of data specified in step SB2 is 50 kilobytes or more, the control unit 100 specifies the value of the initial window size as “3”, and conversely, is specified in step SB2. When the data amount is less than 50 kilobytes, the control unit 100 specifies the initial window size value as “10”. Then, the control unit 100 transfers the segment received in step SB1 while performing window control with the initial window size specified in step SB3 (step SB4). As described above, by using the relay device 230 according to the second embodiment, the same effect as that of the first embodiment described above can be obtained.

  In the second embodiment described above, the case where the segment received in step SB1 is directly transmitted in step SB4 has been described. However, a storage area (hereinafter referred to as a cache area) for storing the segment received in step SB1 is provided in the volatile storage unit 120a (or non-volatile storage unit 120b), and the received segment is temporarily stored in this cache area. After that, it is of course possible to transmit in step SB4. In this way, even if the communication speed in the wireless communication network 20 and the communication speed in the Internet 40 are different (for example, when the former is slower), the relay device 230 adjusts the difference between the two communication speeds. It becomes possible to do. Thereby, for example, even when the former is extremely slow compared to the latter, the amount of segments flowing into the wireless communication network 20 can be adjusted according to the communication speed, so that the wireless communication network 20 is congested. There is an effect that it is avoided to fall into.

[C: Modification]
The best mode for carrying out the present invention has been described above. However, it goes without saying that the following modifications may be added to the above-described embodiments.

(C-1: Modification 1)
In each of the above-described embodiments, the case where the advertisement window size notified from the communication terminal 10 is sufficiently large and the transmission window size is always equal to the congestion window size has been described. However, the smaller of the advertisement window size and the congestion window size is not set as the transmission window size, but always the congestion window size (the initial window size specified by the above-described specific function or the initial window size is set as the initial value). Of course, the transmission window size may be set as a calculation result calculated by a predetermined algorithm.

(C-2: Modification 2)
In each of the above-described embodiments, the case where the initial window size representing the communication speed when transmitting the content is used as the control parameter indicating the mode of window control to be performed when transmitting the content to the communication terminal 10 has been described. However, such control parameters are not limited to the initial window size. For example, it may be data indicating an increment when the congestion window size (or transmission window size) is increased in response to reception of the confirmation response. Even in such an aspect, the data can be transmitted at an appropriate communication speed according to the data amount of the content to be transmitted to the communication terminal 10. The control parameter is not limited to data indicating the communication speed at the time of transmitting the content. For example, data indicating availability of various options such as a window enlargement option and a time stamp option, for example, ECN Data indicating whether or not various algorithms such as these can be used may be used. By doing in this way, there exists an effect that it becomes possible to add a suitable option according to the data amount of the content which should be transmitted to a communication terminal, and to perform window control using a suitable algorithm.

(C-3: Modification 3)
In each of the above-described embodiments, the case has been described where the control parameter indicating the initial window size (that is, the communication speed) when transmitting the content is specified according to the data amount of the content to be transmitted to the communication terminal 10. However, the transmission device 50 (or the relay device 230) is provided with detection means for detecting the usage status of the wireless communication network 20 accommodating the communication terminal 10 and the load associated with the relay device 30 (or the relay device 230). Of course, the control parameter may be determined in consideration of the load detected by the detecting means. Specifically, when the usage status of the wireless communication network 20 is high or when the load on the relay device 30 (or the relay device 230) is large, the control parameter corresponding to the lower communication speed is specified. You can do that. By doing so, it is possible to prevent the wireless communication network 20 and the relay device 30 (or the relay device 230) from becoming congested.

(C-4: Modification 4)
In each of the above-described embodiments, a case has been described in which software for causing the control unit 100 to realize functions unique to the transmission device and the relay device according to the present invention is stored in the volatile storage unit 120b in advance. However, for example, the segment transmission software and the relay software are recorded on a computer-readable recording medium such as a CD-ROM (Compact Disk Read Only Memory), and a general computer using the recording medium is used. Of course, the software may be installed in the apparatus. If it does in this way, there exists an effect that it becomes possible to provide the same function as the transmitter and relay device concerning the present invention to the transmitter and relay device included in the existing communication system.

It is a figure which shows the structural example of the communication system which concerns on 1st Embodiment of this invention. 3 is a diagram illustrating a configuration example of the transmission device 50. FIG. It is a figure which shows an example of the storage content of the control parameter management table stored in the non-volatile storage part 120b of the transmitter 50. It is a flowchart which shows the flow of the segment transmission process which the control part 100 of the transmitter 50 performs. It is a figure which shows the structural example of the communication system which concerns on 2nd Embodiment of this invention. 3 is a diagram illustrating a configuration example of the relay device 230. FIG. 4 is a flowchart showing a flow of relay processing performed by the control unit 100 of the relay device 230.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Communication terminal, 20 ... Wireless communication network, 30, 230 ... Relay apparatus, 40 ... Internet, 50, 250 ... Transmission apparatus, 100 ... Control part, 100 ... Communication IF part, 110a ... 1st communication IF part, 110b ... Second communication IF unit, 120 ... storage unit, 120a ... volatile storage unit, 120b ... non-volatile storage unit, 130 ... bus.

Claims (7)

A storage means for storing a control parameter indicating a mode of window control for each data amount of data to be transmitted;
While specifying the data amount of transmission data to be transmitted to the communication terminal via the communication network, the window control performed when transmitting the transmission data to the communication terminal based on the identification result and the storage contents of the storage means A specifying means for specifying a control parameter indicating an aspect;
A transmission apparatus comprising: transmission means for transmitting the transmission data to the communication terminal while performing window control in a mode indicated by the control parameter specified by the specifying means. The transmission device according to claim 1, wherein the control parameter is data representing a communication speed when the transmission data is transmitted to the communication terminal. Detecting means for detecting a load applied to the communication network;
The specification unit is configured to specify a control parameter representing a communication speed slower than a control parameter corresponding to a data amount of the transmission data when the load detected by the detection unit is high. The transmitting device according to 1. Storage means for storing a control parameter indicating a mode of window control for each data amount of data to be transferred;
Receiving means for receiving transmission data transmitted from the transmission device to the communication terminal via the communication network;
While the data amount of the transmission data received by the receiving means is specified, the mode of the window control performed when transferring the transmission data to the communication terminal based on the specifying result and the storage contents of the storage means is shown. A specifying means for specifying the control parameter;
A relay apparatus comprising: transfer means for transferring the transmission data to the communication terminal while performing window control in a mode indicated by the control parameter specified by the specifying means. Cache means for storing transmission data received by the receiving means;
The transfer means transfers the transmission data stored in the cache means to the communication terminal while performing window control in a mode indicated by the control parameter specified by the specifying means. The relay device described. Computer equipment,
Storage means for storing a control parameter indicating a mode of window control for each data amount of data to be transmitted;
While specifying the data amount of transmission data to be transmitted to the communication terminal via the communication network, the window control performed when transmitting the transmission data to the communication terminal based on the identification result and the storage contents of the storage means A specifying means for specifying a control parameter indicating an aspect;
A program that functions as a transmission unit that transmits the transmission data to the communication terminal while performing window control indicated by the control parameter specified by the specifying unit. Computer equipment,
Storage means for storing a control parameter indicating a mode of window control for each data amount of data to be transferred;
Receiving means for receiving transmission data transmitted from the transmission device to the communication terminal via the communication network;
While the data amount of the transmission data received by the receiving means is specified, the mode of the window control performed when transferring the transmission data to the communication terminal based on the specifying result and the storage contents of the storage means is shown. A specifying means for specifying the control parameter;
A program that functions as transfer means for transferring the transmission data to the communication terminal while performing window control in a mode indicated by the control parameter specified by the specifying means.

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