JPH11149448A - Network system, client terminal and relay server - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network system with which data are efficiently transmitted by converting data corresponding to conditions such as a communication state or the throughput of a terminal. SOLUTION: When acquiring data D1 from a server 30, a data-with-index acquisiton request transmitting means 21 generates and transmits a data acquisition request C with index by adding an index concerning data transmission information to the data acquisition request. A data converting means 41 converts the data D1 acquired from the server 30, based on the index. A data storage means 42 stores converted data D2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system, a client terminal and a relay server, and more particularly to a network system for transmitting data in a client-server type network, a client terminal for acquiring data from a server for providing information, and information provision. The present invention relates to a relay server that performs relay control between a server that performs data transfer and a client terminal that acquires data from the server.

[0002]

2. Description of the Related Art In recent years, with the advancement of network technology, the momentum of multimedia communication for performing communication by combining text, images, voices, and the like in an integrated manner has been rapidly increasing.

In multimedia communication, an information providing server is used to provide various services to other terminals on a network. The information providing server transmits various multimedia data such as text data, image data, audio data, and the like to the partner terminal.

FIG. 17 is a diagram showing a data transmission configuration between an information providing server and a terminal. The terminal 200 connects to the communication network 50 using an attached communication network interface (not shown), and the information providing server 300 connects to the communication network 50 via the gateway 400. Then, communication is performed between the terminal 200 and the information providing server 300.

When the terminal 200 downloads data from the information providing server 300, a physical or virtual connection is established between the terminal 200 and the information providing server 300. Then, a data acquisition request is made from the terminal 200 on this connection, and the data is transmitted from the information providing server 300.

[0006] In this case, the data acquisition request from the terminal 200 specifies the name of the data possessed by the information providing server 300, and the information providing server 300 having obtained the data obtains the data corresponding to the data name from the terminal 200. Transmit to Thereafter, the connection is disconnected or an acquisition request for another data is made again.

[0007]

However, in the conventional data transmission as described above, the information providing server 300 transmits the stored data irrespective of the state of the communication network 50. Therefore, for example, a large amount of data is sent even when the transmission capacity of the communication network 50 is low, and there is a problem that it takes time for the terminal 200 to acquire the data.

[0008] Further, the information providing server 300 transmits the stored data as it is, without considering the type and processing capability of the partner terminal. For this reason, there are problems that the terminal 200 does not have a memory enough to store data, or that display data that exceeds the display capability of the terminal 200 is transmitted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a network system that performs data conversion in accordance with conditions such as a communication state and a processing capability of a terminal to efficiently transmit data. With the goal.

It is another object of the present invention to provide a client terminal that transmits data after adding conditions such as a communication state and a processing capability of the terminal to the data, and efficiently transmits data.

Still another object of the present invention is to provide a relay server that performs data conversion according to conditions such as a communication state and a processing capability of a terminal to efficiently transmit data.

[0012]

According to the present invention, in order to solve the above-mentioned problems, in a network system for transmitting data in a client-server type network, a server for providing information and a server for obtaining data from the server are provided. A client terminal including an indexed data acquisition request transmitting unit for generating and transmitting an indexed data acquisition request by adding an index relating to data transmission information to the data acquisition request, and the data acquired from the server based on the index. And a data storage means for storing data after the conversion, and a relay server for performing relay control between the server and the client terminal. Provided.

Here, when acquiring data from the server, the indexed data acquisition request transmitting means adds an index relating to data transmission information to the data acquisition request, and generates and transmits an indexed data acquisition request. The data conversion means converts the data obtained from the server based on the index.
The data storage means stores the converted data.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the principle of a network system according to the present invention. The network system 10 has a client-server type network configuration and transmits data through a communication network 50.

The network system 10 includes a server 30 for providing information, a client terminal 20 for acquiring data from the server 30, and a relay server 40 for controlling relay between the server 30 and the client terminal 20. You.

The indexed data acquisition request transmitting means 21
When the client terminal 20 acquires data from the server 30, an index relating to data transmission information is added to the data acquisition request, and an indexed data acquisition request C is generated and transmitted.

Here, the data transmission information means the communication state of the communication network 50 and the processing capability of the client terminal 20 itself. The relay server 40 transmits the indexed data acquisition request C to the server 30 and acquires the corresponding data D1 from the server 30.

The data conversion means 41 converts the data D1 obtained from the server 30 based on the index, and the data storage means 42 stores the converted data D2. Thereafter, the relay server 40 transmits the converted data D2 to the client terminal 20.

The relay control performed by the relay server 40 is to convert data transmitted and received between the client terminal 20 and the server 30 based on an index, or to convert data without conversion if conversion is not necessary. Transmission control such as transmission.

Next, a specific configuration of the network system 10 of the present invention will be described. FIG. 2 is a diagram illustrating a configuration of the network system 10. Here, the client terminal 20 of the present invention (hereinafter referred to as the mobile terminal 20)
It has a PHS function. Also, the mobile terminal 20,
It is assumed that the server 30 performs data transmission on the Internet.

The mobile terminal 20 performs wireless communication via the base station 51. The base station 51 connects to the ISDN network 52.
The ISDN network 52 and the LAN 54 are connected via an access point 53 serving as a reception port for accessing each other.

The LAN 54 is connected to a relay server 40 for performing relay control between the portable terminal 20 and the server 30, and the server 30 having the database 30a. Next, a protocol stack in data transmission in the network system 10 will be described. FIG. 3 is a diagram showing a protocol stack.

The layer configuration of the portable terminal 20 is H
TTP (Hyper Text Transfer Protocol), TCP / I
P, PPP, PIAFS, and STD28. The layer configuration on the mobile terminal 20 side of the base station 51 is H
TTP, TCP / IP, PPP, PIAFS, STD2
8. The layer configuration of the base station 51 on the ISDN network 52 side includes HTTP, TCP / IP, P
It consists of PP, PIAFS, and ISDN.

The layer configuration of the access point 53 on the ISDN network 52 side includes HTTP, TCP / IP, P
It consists of PP, PIAFS, and ISDN. The layer configuration on the LAN 54 side of the access point 53 is H
It is composed of TTP, TCP / IP, MAC, and physical.

The layer configuration of the relay server 40 is HTT
P, TCP / IP, MAC, and physical. The layer configuration of the server 30 is HTTP, TCP / IP, MA
C, composed of physics.

As described above, the HTML (Hy
A protocol HTTP for exchanging hypertext of Per Text Markup Language (HTTP) is used, and TCP / IP is used in a layer below it. And the layers below this use a protocol to match each device,
Protocol conversion is appropriately performed in each device.

At the time of data transmission, first, PPP is used between the portable terminal 20 and the access point 53, and
Establish a one-to-one connection. Further, in this case, PIAFS is used between the portable terminal 20 and the access point 53. PIAFS is a transmission method for performing error-free transmission between terminals that support the PHS transmission method.

Here, the PHS at the access point 53
It is assumed that error free in the wireless section is guaranteed and data is sent to the LAN 54. Next, network system 1
0 will be described in detail. FIG. 4 shows the relay server 40
FIG. 7 is a sequence diagram showing a processing procedure when performing data conversion. [S1] A PIAFS link is established between the mobile terminal 20 and the access point 53. [S2] A PPP link is established on the PIAFS link. Thereby, the mobile terminal 20 and the server 30 are physically connected via the access point 53. [S3] T is set between the mobile terminal 20 and the relay server 40.
A CP / IP link is established. [S4] The mobile terminal 20 issues a data acquisition request by an HTTP request on a TCP / IP virtual connection.

In this case, in the present invention, an index relating to the processing capability and the communication state of the portable terminal 20 is included in the data acquisition request, and an indexed data acquisition request is generated and transmitted. To generate an indexed data acquisition request, a URI (Universal Re
There is a case where the indicator is included in the source identifier, and a case where the indicator is included in the HTTP header. Details will be described later. [S5] TC between the relay server 40 and the server 30
A P / IP link is established. [S6] The relay server 40 sends a data acquisition request to the server 30.
Send to [S7] The server 30 uses the database query language SQ
Using L, the requested data is extracted from the database 30a and transmitted to the relay server 40. [S8] TC between the relay server 40 and the server 30
The P / IP link is disconnected. [S9] The data conversion means 41 of the relay server 40 converts the data based on the index. And the relay server 4
0 writes the converted data to a disk (corresponding to the data storage means 42) on the relay server 40.

By writing and storing the converted data in this manner, the next time a data acquisition request to which the same terminal condition and the same communication condition index are added is received, the server 30 can be accessed without newly accessing it. The converted data may be sent back to the mobile terminal 20. Note that the mobile terminal 20
Has a PHS function, electric field strength and the like are described in the index as communication conditions. [S10] The relay server 40 transmits the converted data to the mobile terminal 20. [S11] The TCP / IP link between the relay server 40 and the portable terminal 20 is disconnected. [S12] The mobile terminal 20, the access point 53,
The PPP link is disconnected. [S13] The mobile terminal 20, the access point 53,
The link of PIAFS is disconnected.

As described above, the network system 10 of the present invention transmits an indexed data acquisition request, converts the data acquired from the server 30 by the relay server 40 based on the index, and then transmits the data to the portable terminal 20. It was configured to transmit.

Thus, the server 30, the relay server 40
And the load on the network can be reduced.
Next, generation of an indexed data acquisition request will be described with reference to FIGS. FIG. 5 is a diagram showing an indexed data acquisition request when an index is included in the URI.

An indexed data acquisition request C1 in the case where an index is included in the URI includes an index 1 following the actual URI 1a.
b is added. The index 1b specifies the state of the data transmission information. In addition, www. hoge. co. j
p is the name of the WWW server 30.

FIG. 6 is a diagram showing an indexed data acquisition request when an index is included in the HTTP header. The indexed data acquisition request C2 includes the index 2 in the HTTP header 2a.
b is added.

The index 2b is embedded in the HTTP protocol using the extension of the HTTP header as described above.
Then, the state of the data transmission information is designated by the index 2b. Note that both the index 1a in FIG. 5 and the index 2b in FIG. 6 indicate that the capability of the mobile terminal 20 is low and the communication quality is poor.

Therefore, when performing data conversion, since the portable terminal 20 has low processing capability and low communication quality, conversion is performed so that data is reduced as much as possible. In particular,
If the data to be communicated is a color image, it may be possible to convert the color image data into 16 gray levels of black and white.

Next, data transmission when terminal conditions and communication conditions are different from the conditions at the time of previous communication will be described. FIG. 7 is a sequence diagram showing a data transmission processing procedure when terminal conditions and communication conditions are different from the previous conditions. The description will be given after the establishment of the PPP link. [S20] A TCP / IP link is established between the portable terminal 20 and the relay server 40. [S21] The mobile terminal 20 issues an indexed data acquisition request on a TCP / IP virtual connection. [S22] The relay server 40 reads the stored original data, and converts the data based on the index. Then, the relay server 40 writes the converted data to the disk. [S23] The relay server 40 transmits the converted data to the mobile terminal 20. [S24] The TCP / IP link between the relay server 40 and the portable terminal 20 is disconnected.

As described above, even in the case of the same data acquisition request, if the terminal conditions and the communication conditions are different from the previous conditions, the data stored in the relay server 40 in advance may be converted. This makes it possible to reduce the load on the server 30 and the load on the network.

Next, data transmission when data in the server 30 is updated will be described. In the above-described sequence, it is assumed that there is no data update in the server 30. However, it is conceivable that the data is actually updated in the server 30 and the data stored in the relay server 40 is out of date.

Therefore, it is necessary for the relay server 40 to know the data update information in the server 30 and perform update control. In this case, the last-modified header in the header of the HTTP response returned from the server 30 is used. this
The last-modified header describes the last update time of the data in the server 30.

The relay server 40 stores the last update time in a file together with the data. Then, when there is a request to acquire the same data from the portable terminal 20 next, when making a data acquisition request to the server 30, the request is made including the last update time.

[0042] This includes if in the HTTP request header.
-modified-since header. When the server 30 receiving the request including this header updates the data more recently than the last update time, the server 30
In response to P, "200OK" is returned, and data is sent back as usual. The subsequent operation of the relay server 40 is the same.

If the last update time has not changed, the server 30 returns "304 not" in the HTTP response.
modified ”and does not send back the data. Therefore, the relay server 40 that has received this HTTP response
Can determine that its own data is the latest, and if necessary, convert it and send it back to the mobile terminal 20.

FIG. 8 is a sequence diagram showing a processing procedure of data transmission with update control when data in the server 30 has not been updated. The description will be given after the establishment of the TCP / IP link. [S30] The mobile terminal 20 transmits an indexed data acquisition request to the relay server 40. [S31] In order to know whether or not the data in the server 30 has been updated, the relay server 40 makes a request including the last update time when making a data acquisition request. [S32] Since the last update time has not changed, the server 30 transmits only the header to the relay server 40. [S33] The relay server 40 knows from the last update time in the header that the data has not been updated, and reads out the data already stored. [S34] The relay server 40 transmits the converted data to the mobile terminal 20.

FIG. 9 is a sequence diagram showing a data transmission processing procedure with update control when data in the server 30 is updated. The description will be given after the establishment of the TCP / IP link. [S40] The mobile terminal 20 transmits an indexed data acquisition request to the relay server 40. [S41] In order to know whether or not the data in the server 30 has been updated, the relay server 40 makes a request including the last update time when making a data acquisition request. [S42] Since the last update time has changed, the server 30 extracts the requested latest data from the database 30a using SQL, which is a database query language, and transmits it to the relay server 40 including the last update time. . [S43] The relay server 40 knows that the data has been updated from the last update time, converts the data based on the index, and writes the data to the disk. [S44] The relay server 40 transmits the converted data to the mobile terminal 20.

Next, a case where data transmission is performed based on the last update time from the portable terminal 20 will be described. The data transmission described above is based on the premise that data is acquired from the mobile terminal 20 for the first time.
It is possible that there is already information within.

For example, there is a case where frequently accessed information is stored in a cache memory (hereinafter, cache) in the portable terminal 20. Also in this case, this is performed using the last-modified header sent from the server 30. That is, when the data has already been stored in the cache of the mobile terminal 20, the mobile terminal 20 acquires the last update time (obtained from the last-modified field) from the cache data.

When an indexed data acquisition request is issued to the server 30, an if-modified-since field is added to the header, and the last update time acquired earlier is added. The relay server 40 that has obtained the data transmits the data to the relay server 4
If it is stored in 0 and newer than the last update time, the data is returned to the mobile terminal 20.

If the update time is the same, only the header of the status code "304n not modified" is returned without returning data. Further, if the data in the relay server 40 is older than the data in the mobile terminal 20, the data is acquired from the server 30. At this time, if the data does not meet the conditions of the mobile terminal 20, the conversion processing is performed based on the index.

FIG. 10 is a sequence diagram showing a data transmission processing procedure when the portable terminal 20 has a cache but the data in the portable terminal 20 is old. In addition, TCP / I
It will be explained after the establishment of the P link. [S50] The mobile terminal 20 transmits an indexed data acquisition request including the last update time. [S51] The relay server 40 knows that the data in the portable terminal 20 is older than the last update time, and reads the converted data. [S52] The relay server 40 transmits the converted data to the mobile terminal 20.

FIG. 11 is a sequence diagram showing a data transmission processing procedure when the portable terminal 20 has a cache and the data in the portable terminal 20 is the latest. In addition, TCP /
Explanation will be given after the establishment of the IP link. [S60] The mobile terminal 20 transmits an indexed data acquisition request including the last update time. [S61] The relay server 40 knows that the data in the portable terminal 20 is the latest from the last update time, and transmits only the header.

FIG. 12 is a sequence diagram showing a data transmission processing procedure when the portable terminal 20 has a cache and the data in the portable terminal 20 is newer than the data in the relay server 40. The description will be given after the establishment of the TCP / IP link. [S70] The mobile terminal 20 transmits an indexed data acquisition request including the last update time. [S71] The relay server 40 knows that the data in the relay server 40 is older than the data in the portable terminal 20 from the last update time, and makes a request including the last update time when making a data acquisition request to the server 30. [S72] The server 30 uses the database query language S
The latest requested data is extracted from the database 30a using QL, and transmitted to the relay server 40 including the last update time. [S73] The relay server 40 converts the acquired latest data based on the index, and writes the converted data to the disk. [S74] The relay server 40 transmits the converted data to the mobile terminal 20.

Next, data conversion will be described. There are various types of multimedia data obtained from the server 30. Here, text data described in HTML, image data in GIF (Graphics Interchange Format), and image data in JPEG format are targeted.

First, consider a case where data is converted in accordance with the HTML data processing capability of the portable terminal 20. H
Many improvements are currently being made to the TML format.

For this reason, if the viewer of the portable terminal 20 can support only the old HTML, the new HTML
L format data cannot be interpreted. FIG. 13 shows an indexed data acquisition request. The viewer 100 has the processing capability of the mobile terminal 20 as HTML.
Indicates that it corresponds to version 1.0 of
This indexed data acquisition request is transmitted.

FIG. 14 is a diagram showing HTML acquired by the relay server 40 from the server 30. Viewer 101 is
The HTML acquired by the relay server 40 from the server 30 based on the data acquisition request from the mobile terminal 20 is shown.

FIG. 15 is a diagram showing HTML after data conversion. The viewer 102 shows the HTML after the data conversion, and the HTML is displayed on the portable terminal 20. That is, the data portion 101a of FIG.
Since it is the HTML version 3.2 format called "ESET>", it cannot be interpreted by the viewer of the portable terminal 20, and can be interpreted only for <BODY> and later.

Therefore, the relay server 40 deletes the data portion 101a that cannot be interpreted, converts the data portion into data as shown in FIG. Next, conversion when data is an image file will be described. There are various types of image files such as color, black and white, high precision, low precision, high quality, and low quality, and the number of pixels also varies.

For example, when the portable terminal 20 is black and white and has a small amount of memory, even if color high-precision and high-quality data is obtained, it cannot be viewed. In addition, a large image cannot be viewed on the mobile terminal 20 whose display size is limited. Furthermore, if you try to transmit large image data when the communication condition is poor, data acquisition will fail on the way,
Data transmission takes time.

FIG. 16 is a diagram showing a conversion table of an image file. The table 110 describes a conversion method for performing appropriate conversion depending on the state of the mobile terminal 20 and the communication state.

For example, if the portable terminal 20 has a processing capability of monochrome display, and if the target format is a GIF, the color image is converted into any of the grayscale 2, 4, 8, or 16 gray scale.

It should be noted that the image size of both GIF and JPEG can be increased or decreased, and GIF can specify the number of colors, but JPEG cannot specify the number of colors. Also, JPE
With G, image quality can be specified, but GIF cannot.

As described above, when acquiring data, the network system 10 of the present invention considers the state of the communication network 50 between the client terminal 20 and the relay server 40 and the processing capability of the terminal itself, and At 40, the data is converted and acquired.

As a result, the amount of data can be reduced, redundant data can be reduced, and data transmission can be performed efficiently. Further, at the time of a data acquisition request, the relay server 40 stores the data after the data conversion, so that only the converted file is accessed for the second and subsequent acquisition requests, so that the load on the relay server 40 and the server 30 can be reduced.

[0065]

As described above, according to the network system of the present invention, when a client terminal acquires data from a server, an index relating to data transmission information is added to the data acquisition request and transmitted, and the relay server transmits the index to the server. After converting the acquired data based on the index, the data is transmitted to the client terminal. This allows the server and
Since data can be transmitted and received between the client terminals according to conditions such as the communication state of the communication network and its own processing capability, efficient data transmission is possible.

Further, the client terminal of the present invention is configured to add an index relating to data transmission information to a data acquisition request and transmit it when acquiring data from the server.
Thus, conditions such as the communication state of the communication network and its own processing capability can be notified to the information providing side, so that efficient data transmission becomes possible.

Further, the relay server of the present invention converts data obtained from the server based on the index and transmits the converted data to the client terminal. Thus, data that meets conditions such as the communication state of the communication network and its own processing capability can be transmitted to the client terminal, so that efficient data transmission becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a network system according to the present invention.

FIG. 2 is a diagram showing a configuration of a network system.

FIG. 3 is a diagram showing a protocol stack.

FIG. 4 is a sequence diagram illustrating a processing procedure when performing data conversion through a relay server.

FIG. 5 is a diagram illustrating an indexed data acquisition request when an index is included in a URI.

FIG. 6 is a diagram illustrating an indexed data acquisition request when an index is included in an HTTP header.

FIG. 7 is a sequence diagram showing a data transmission processing procedure when terminal conditions and communication conditions are different from the previous conditions.

FIG. 8 is a sequence diagram illustrating a processing procedure of data transmission with update control when data in the server is not updated.

FIG. 9 is a sequence diagram illustrating a data transmission processing procedure with update control when data in the server is updated.

FIG. 10 is a sequence diagram showing a data transmission processing procedure when the portable terminal has a cache but the data in the portable terminal is old.

FIG. 11 is a sequence diagram showing a data transmission processing procedure when the portable terminal has a cache and the data in the portable terminal is the latest.

FIG. 12 is a sequence diagram showing a data transmission processing procedure when the portable terminal has a cache and the data in the portable terminal is newer than the data of the relay server.

FIG. 13 is a diagram showing an indexed data acquisition request.

FIG. 14 is a diagram showing HTML acquired by the relay server from the server.

FIG. 15 is a diagram showing HTML after data conversion.

FIG. 16 is a diagram showing a conversion table of an image file.

FIG. 17 is a diagram showing a data transmission configuration between an information providing server and a terminal.

[Explanation of symbols]

10 network system, 20 client terminal, 21 indexed data acquisition request transmitting means, 30
... Server, 40 relay server, 41 data conversion means, 42 data storage means, C data acquisition request with index, D 1 data, D 2 data after conversion.

Claims (14)

[Claims] 1. A network system for transmitting data in a client-server type network, comprising: a server for providing information; and an index for data transmission information added to a data acquisition request when acquiring data from the server. A client terminal including an indexed data acquisition request transmitting unit that generates and transmits an attached data acquisition request, a data conversion unit that converts the data acquired from the server based on the index, and stores the converted data. A network server comprising: a data storage unit; and a relay server configured to control relay between the server and the client terminal. 2. The network system according to claim 1, wherein the indexed data acquisition request transmitting unit uses a communication state of a communication network and its own processing capability as the data transmission information. 3. The network system according to claim 2, wherein the client terminal has a mobile phone function, and uses an electric field strength as the index relating to a communication state of the communication network. 4. The network system according to claim 1, wherein
The network system according to claim 1, wherein the data transmission is performed using a protocol. 5. The network system according to claim 4, wherein the indexed data acquisition request transmitting unit uses the version number of the HTML as the index when the data is HTML. 6. The network system according to claim 1, wherein the indexed data acquisition request transmitting unit uses its own displayable size as the index when the data is an image file. 7. The network system according to claim 6, wherein said data conversion means converts said data to be equal to or less than said displayable size when said index is a displayable size of said client terminal. 8. The network system according to claim 1, wherein the indexed data acquisition request transmitting unit uses the number of colors that can be represented by the client terminal as the index when the data is GIF. 9. The data conversion means, when the data is image data and the communication state of the communication network is poor, converts the image data to reduce the quality of the image data. The network system according to claim 1, wherein 10. The relay server, if the data requested from the client terminal is the same again, without accessing the server, the relay server responds to the data stored in the data storage unit. The network system according to claim 1, wherein relay control is performed. 11. When the data in the server is updated, the relay server obtains the updated data from the server, performs the relay control, and updates the data in the server. 2. The network system according to claim 1, wherein the relay control is performed on the data in the data storage unit when the data is not stored. 12. The relay server performs the relay control on one of the data stored in the client terminal and the data stored in the data storage means, which is newer. The network system according to claim 1, wherein: 13. A client terminal for acquiring data from a server that provides information, wherein, when acquiring the data from the server, an index relating to data transmission information is added to the data acquisition request to generate an indexed data acquisition request. A client terminal having indexed data acquisition request transmission means for transmitting the data. 14. A server that provides information, and a relay server that performs relay control between a client terminal that obtains data from the server and a data conversion unit that converts the data obtained from the server based on the index. A relay server, comprising: data storage means for storing data after conversion.