JP2003233524A - Data transfer method, data transfer device, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proxy device capable of reducing a load on a network. <P>SOLUTION: In transfer of a reply data with new contents from a server side proxy 30 to a client side proxy 40, a hash function used in both proxies is decided, and the data, the hash function name, and a fingerprint calculated using the hash function are associated with each other and registered in a fingerprint cache. In transfer of the data registered in the fingerprint cache from the server side proxy 30 to the client side proxy 40, the hash function and the fingerprint are transferred instead of the reply data. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer method, a data transfer device and a program for transferring data for another device.

[0002]

2. Description of the Related Art A client-server type information system is widely used, which comprises a server that provides various services via a network and a client that requests a desired service server. In particular, a WORLD W that consists of a WEB server and a client that communicate using the HTTP protocol on the Internet.
The IDE WEB system (or simply called WEB) is a client / server type information system which is very widely used. Normally, a server program runs on the server, and a predetermined tool (program) such as a browser runs on the client. The contents of services provided on the Internet are also wide-ranging, and information such as characters, still images, moving images, and audio (such as websites, e-mails, digital contents, etc.) and programs are provided via the network. Various services such as distribution or transfer services, electronic store services for selling products, reservation services for seats, rooms, etc., intermediary services for various contracts already exist, and new services one after another. Has appeared.

By the way, a client such as WEB
In the server type information system, basically, regardless of the form of the provided service, the data is transferred between the client and the server to provide the service. Therefore, the capacity (bandwidth) of the network used for communication between the client and the server is likely to become the bottleneck of the entire system.
Therefore, cache technology is usually used to reduce the load on the network.

In the WEB system, many browsers and the like operating on the client use a cache mechanism, and cache recently accessed data.
On the WEB, since information and services are specified by the name called URL, access is performed, so the cache on the client can cache the data returned as a result of the information and services requested to the WEB server in the past. , Is recorded in the cache in association with the URL. In this case, the same UR that is in the cache
When it is possible to determine that the response data in the cache is not outdated when there is a request for L information or a service, the data can be returned to eliminate communication with the WEB server.

When there are a plurality of users in a LAN in a company office, a LAN in a research institution, a LAN in a home, etc., a proxy server is placed between the LAN and the Internet, and a cache mechanism is provided in the proxy server. I often do it. The cache in the client (for example, the cache of the browser) operates as a cache dedicated to the client user, while the cache of the proxy server on the LAN operates as a cache shared by a plurality of client users. Therefore, in the latter case, the cache is effective even when the URL accessed by another person (other client) in the past is accessed.

[0006] In the WEB, communication between the client and the server is performed by a protocol called HTTP. The HTTP protocol is composed of a "request message" sent from the client to the server and a "reply message" for returning a response from the server to the client.

The request message consists of a "request header" and a "request body". In the request header, U that specifies the information or service you want to access
The RL, the method name indicating the type of access, and other various information necessary for access are entered. In the request body,
Enter the data to send to the server. The data contained in the request body is also called "request data".

The reply message is composed of a "reply header" and a "reply body". The reply header contains information such as the status of the processing result, and the reply body contains data such as the requested information and the processing result of the requested service. The data contained in the reply body is also called “reply data”.

As the method of the request message, there are a "GET method" for reading out information on the server, a "PUT method" for writing user's data to the server, and a "POST method" for sending back the result processed in response to the request. , Is the main one used to access information and services. Others, DELET
Methods such as E are defined.

In many cases, the request body of the GET method request message and the reply body of the PUT method reply message are empty. POST
The request body of the request message of the method contains information used for processing on the server side as necessary, and the reply body of the reply message of the POST method contains data of the result of the processing.

The data read from the server by the GET method is "dynamic data" generated on the server side each time the data is read.
Then, the data already stored on the server side can be divided into “static data” that is sent back as it is. Of these, the dynamic data may have different contents each time the same URL is read, so in most cases, the server sends back a non-cacheable designation in the header of the reply message. Therefore, it is only the static data that is cached in the WEB data. This static data can be divided into "shared data" that may be referred to by an unspecified number of users, and "private data" that controls access so that only certain users can access by authenticating the user. . The former shared data can be cached in any cache. However, the latter private data cannot be cached by a shared cache such as a proxy server (since private data must be authenticated by the server and sent back to the user). However, private data such as a browser can be cached even with private data.

Since the POST method returns the result of processing on the server side, the server generally sends a result by putting a non-cacheable designation in the header of the reply message. Therefore, it is usually not cached.

Since the PUT method sends data to the server, the cache does nothing.

[0014]

In the conventional WEB cache, static contents are cached. In the past, information and services published on the WEB were not frequently updated, and many were published to an unspecified number of people, so the proportion of static content was very high, and The cache technology was also effective in reducing the load on the network.

However, the WEB-based ASP (A
application Service Provid
As described above, as a system in which a user uses a WEB browser to access information and services on a server via a network has become widespread, the amount of data that the conventional cache technology cannot handle is increasing as described below. -There are many private data because the users are authenticated and the users who can access are restricted. -Many dynamic data are generated by referring to the back-end database. -The POST method is often used for form processing and retrieval. -The PUT method is often used to share information within the group. As a result, the cache technology alone is no longer effectively functioning as a method for reducing the load on the network.

The present invention has been made in consideration of the above circumstances, and a data transfer method and a data transfer apparatus equipped with a cache technology / compression technology capable of further reducing the load of a network connecting the data transfer apparatuses. And to provide a program.

[0017]

The present invention provides a first data transfer device having a plurality of calculation methods for compressing data, and a second data transfer apparatus having a plurality of calculation methods for compressing data.
The data transfer device is connected via a communication path,
A data transfer method capable of acquiring data requested by the first data transfer device by making a data request from the first data transfer device to the second data transfer device, the data transfer method comprising: From the plurality of calculation methods and the plurality of calculation methods included in the second data transfer apparatus, one calculation method included in both data transfer apparatuses is determined, and the second data transfer apparatus requests the data request from the first data transfer apparatus. To obtain data corresponding to the above, compress the data by the determined one calculation method, and confirm whether or not the data compressed by the one calculation method has been stored in the storage device provided in the second data transfer device. If the confirmation result indicates that the data is not stored, the data, the compressed data, and the one calculation method are stored in the storage device in association with each other, and the data is transferred to the first data transfer device. , The If certification result already stored is the data transfer method to forward the compressed data to the first data transfer device.

More preferably, the determination of the one calculation method is
The first data transfer apparatus receives identification information from the second data transfer apparatus, the identification information indicating each of the plurality of calculation methods included in the second data transfer apparatus, and the plurality of calculation methods included in the first data transfer apparatus. It is only necessary to determine one from among those that match the identification information indicating each of the above, and transmit the determined identification information to the second data transfer device.

Further, according to the present invention, the data transfer device is provided with a first communication in which the data transfer device is provided with a compression means capable of compressing data by each of a plurality of calculation methods, and a storage means for storing identification information indicating the plurality of calculation methods in advance. A data transfer method for performing data transfer with another data transfer device via a communication path, wherein identification information indicating a plurality of calculation methods of the other data transfer device is received from the communication path, and the storage information is stored. One of the identification information of the matching calculation method is selected from the identification information of the plurality of calculation methods stored in the means and the received identification information of the plurality of calculation methods, and the calculation method indicated by the identification information is used. Which is determined as the calculation method to be performed, and the identification information of the determined calculation method is transmitted to the first communication path, and data or compressed data obtained by processing the data from the first communication path by the determined calculation method. Received this If the received data was data,
The data is compressed by the compression means according to the determined calculation method, and the calculation method, the compressed data compressed and the data are stored in the cache means provided in the data transfer device in association with each other. If it is, based on the determined calculation method and the processing data, to obtain the corresponding data from the cache means,
The data transfer method is such that the data received from the first communication path or the acquired data is transmitted to the second communication path. Note that the present invention related to a method is also an invention related to an apparatus, for causing a computer to execute a procedure corresponding to the present invention (or for causing a computer to function as a unit corresponding to the present invention, or for a computer according to the present invention. It also holds as a program) to realize the corresponding function.

According to the present invention, the data, the compressed data thereof, and the name of the method by which the compressed data is generated are held in association with each other between the data transfer devices, and for the data holding these correspondences, the data is stored. By transferring the compressed data and the method name instead of transferring the method, it is possible to reduce the amount of transfer data between the data transfer devices, even when the method is upgraded or a plurality of method names are mixed. .

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The case where the WAN is the Internet, the client is connected to the user office LAN, and the HTTP protocol is used will be described below as an example. Of course, the present invention is not limited to the WA.
Even if N is other than the Internet, the client is installed in a home LAN other than the office, or a protocol other than the HTTP protocol is used, it is applicable.

FIG. 1 shows a basic configuration example of a computer network system to which the present invention is applied. In this configuration example, between the local area network (LAN) 12 in the ASP server center 2 and the local area network (LAN) 16 in the user office 4,
Wide area network (W
The server 20 in the ASP server center 2 and the client 50 in the user office 4 are connected to each other via the LAN 12, WAN 14, LAN 16
It is possible to communicate via. One or a plurality of servers are connected to the LAN in the ASP server center, and one or a plurality of clients are connected to the LAN in the user office.

The WEB-based ASP provides services by various application programs from the server 20 installed in the server center 2 via the WAN 14, and the user uses a WEB browser or the like on the client installed in the office 4. To access those services.

In such a usage mode, the effective communication capacity (bandwidth) of the network connecting the LAN 16 in the user office and the LAN 12 in the server center, particularly the wide area network 14 such as the Internet, is determined by the LAN 12 in the server center and the user. LAN 1 in the office
It is lower than 6, which causes a bottleneck in performance, causes communication delay, and causes a problem that application response performance is degraded.

Therefore, in this embodiment, as shown in FIG. 2, the LAN 12 in the server center and the L in the user office.
At both ends of the wide area network 14 connecting to the AN 16, a server side proxy 30 and a client side proxy 40 are provided.
These two modules are installed, and the fingerprint compression (FP compression) described later is performed between them to reduce the communication data amount, thereby eliminating the bottleneck of the wide area network.

The server 20, the server-side proxy 30, the client-side proxy 40, and the client 5 of this embodiment
Each of 0 can be realized by operating software (server program, server-side proxy program, client-side proxy program, client program) on a computer. In this case, software such as an OS having a desired function of the computer, driver software, packet communication software, encryption software, or hardware such as a communication interface device, an external storage device, an input / output device, or the like is mounted or connected as necessary. To be done. Further, in this case, in order to input information from the user or the administrator or to present the information to the user, the graphical user interface (G
UI) is preferably used.

On the client 50 used by the user to use the service, for example, W is used according to the purpose.
A program such as an EB browser operates. The user uses the service, for example, by issuing a request message from a WEB browser to a server that provides a desired service such as information transfer or order reception via the Internet and receiving a reply message, or by repeating this as appropriate. . Of course, instead of general-purpose software such as a WEB browser, other software such as dedicated software for using a specific service may be used. Moreover, the client may be, for example, a mobile phone terminal having an Internet function, instead of a general-purpose computer.

A predetermined server program operates on the server 20 to provide the user of the client 20 with a service unique to the server site.

The server side proxy 30 is, as shown in FIG.
It can be implemented by connecting to both the LAN 12 and the WAN 14 in the server center and being installed so as to operate as a transparent proxy. Further, as shown in FIG. 3, it may be installed on the LAN 12 in the server center for implementation. Further, as shown in FIG. 4, the function of the server-side proxy 30 may be incorporated in the server 20.

Similarly, the client side proxy 40 is
As shown in FIG. 2, the LAN 16 in the user office and the WAN 1
4 and can be installed and implemented to operate as a transparent proxy. Further, as shown in FIG. 3, it can be installed and implemented on the LAN 16 in the user office. Further, as shown in FIG. 4, the function of the client-side proxy 40 may be incorporated into a browser or the like operating on the client 50. Alternatively, the client-side proxy 40 for personal use may be operated on the operating client 50 such as a browser.

The server side proxy 30 and the client side proxy 40 may have the same form as shown in FIGS. 2 to 4 or the like, or may have different forms.

Each of the server side proxy 30 and the client side proxy 40 of this embodiment has a cache mechanism called a fingerprint cache (FP cache). The fingerprint cache is
By the name called Fingerprint (FP), HT
Records and manages data exchanged by the TP protocol.

As shown in FIG. 5, the fingerprint is calculated by a predetermined calculation method (hash function in the example of FIG. 5) from the content of data (content in the example of FIG. 5) exchanged by the HTTP protocol. It is a short number that is determined. This number may be variable length,
From the viewpoint of ease of processing, fixed-length numbers are easier to handle.

The fingerprint calculation method is as follows:
Well-known hash functions such as MD-5 and SHA-1 can be used. These hash functions are
It is used for digital signatures on data, and given arbitrary data, it can be converted to a 128-bit numerical value for MD-5 and a 160-bit numerical value for SHA-1. The characteristics of these hash functions are:
If two data X1 and X2 are given and the data X1 and the data X2 are the same, the hash value calculated for the data X1 and the hash value calculated for the data X2 are equal, but two different Given that the data A and B are given, the hash value calculated for the data A and the hash value calculated for the data B will differ with a very high probability (in principle , Different 2
The calculated hash value may be the same for each of the two data A and B, but the probability is small enough to be ignored in practice).

In the present embodiment, if a single (predetermined) fingerprint calculation method can be applied to all the server-side proxies 30 and all the client-side proxies 40, the calculation method need not be considered. I can handle it. However, in reality, as shown above, WA
Since N14 is assumed to be the open world Internet, various devices other than the server-side proxy 30 and the client-side proxy 40 of the present embodiment are connected, and the server-side proxy 30 of the present embodiment is connected. Even if the client-side proxy 40 is connected, there is a high possibility that different calculation methods will be used depending on individual circumstances.

Therefore, as shown in FIG. 6A, the fingerprint cache (60 in the figure) of the server-side proxy 30 and the client-side proxy 40 has a data body (FIG. 6) exchanged in the past by the HTTP protocol. 61) is recorded and managed with the fingerprint value (62 in the figure) calculated from the data as a name, and the fingerprint method (fingerprint method indicating which fingerprint method was used). 6 in the figure
3) is also managed at the same time. In FIG. 6A, the fingerprint method 63 is managed for each of the fingerprint 62 and the data body 61, but the fingerprint method 63 is not limited to this method, and for example, the fingerprint method 63 as shown in FIG. 6B. A method of managing the fingerprint 62 and the data body 61 for each may be used. In the method of FIG. 6B, when the data body 61 is searched from the fingerprint 62, if the calculation method of the fingerprint is known, it is not necessary to search for the data of the different calculation method, and thus faster processing is possible.

When the fingerprint cache method is applied and the data is transferred from the server-side proxy 30 to the client-side proxy 40 by the HTTP protocol, for example, the server-side proxy 30 is designated with the fingerprint of the data. If the data corresponding to the fingerprint is stored in the fingerprint cache, the data (data with the same contents) has been transferred in the past, so do not transfer the data. To the corresponding fingerprint value and calculation method. The client-side proxy 40 that has received the fingerprint value and the calculation method can reproduce the data to be transferred by fetching the data corresponding to the fingerprint value from the fingerprint cache by the calculation method. . With this method (that is, data compression → data transfer → data decompression), if the same data as the one sent in the past is used, all that is required is to send the calculation method and the fingerprint value, so that the amount of data flowing through the network is greatly increased. Can be reduced.

For the sake of explanation, when transferring data between the server side proxy 30 and the client side proxy 40, a message cache is used by using the fingerprint cache.
The compression of the transfer information amount by replacing the body data with the fingerprint is called fingerprint compression (FP compression).

It should be noted that, between the server side proxy 30 and the client side proxy 40, all messages are subjected to FP compression (that is, a process for replacing data with a fingerprint using a fingerprint cache is performed. However, in order to exclude the application to those for which the effect of fingerprint cache cannot be expected, for example, the message that satisfies a predetermined condition is set to FP
It may be excluded from the application of compression (always transferred without FP compression).

The predetermined condition in this case is that predetermined information is described in the message header, for example. Specifically, for example, information indicating a GET method and information indicating a request are described in the message header. Another example of the predetermined condition is that the transferred data is null or has a very short size.

Of course, there are various variations other than the above. Further, a plurality of conditions may be combined and used.

Next, referring to FIGS. 7 to 13, the inter-proxy message format (for the message to which the FP compression is applied) at the time of data transfer between the server side proxy 30 and the client side proxy 40. Will be described.

When data is transferred between the server-side proxy 30 and the client-side proxy 40, the message to which FP compression is applied is a message in which the data is FP-compressed and replaced with a fingerprint (a message at the time of compression). And a message that is not FP-compressed but carries data (a message when uncompressed).

The message format at the time of non-compression is
Used when the data contained in the message is not registered in the fingerprint cache. On the other hand, the message format at the time of compression is used when the data included in the message is registered in the fingerprint cache.

On the decompression side (reception side), the reception of the message in the uncompressed format allows the data to be registered in the fingerprint cache.

FIG. 7 shows an example of the message format. (A) is the uncompressed message, (b)
Is the message at the time of compression. Each header portion includes various header information used in a normal reply message, and identification information indicating whether or not this message is compressed by the FP method. In this example, the identification information of (a) is "0" indicating a message at the time of non-compression, and the identification information of (b) is "1" indicating a message at the time of compression. On the other hand, the body part
There is a difference between uncompressed and compressed. That is, FIG.
Data is placed in the uncompressed body portion of FIG. 7A, and F instead of the data of the compressed body portion of FIG. 7B.
The FP method indicating the P calculation method and the fingerprint (FP) value obtained by the calculation method are listed.

Further, at the time of non-compression, instead of FIG. 7A, a fingerprint method and a fingerprint may be included in addition to the data of the body portion as shown in FIG. 7A '. . In this way, when the decompression side registers the fingerprint cache for the data, by using the fingerprint, it is possible to save the trouble of newly obtaining the fingerprint from the data.

Also, the client side proxy 40 uses a predetermined F used when transferring the message format.
If the P method is known, the message format excluding the FP method from the message format of FIG.
It may be in a format (not shown). Similarly, FIG.
A message format (not shown) obtained by removing the FP method from the message format of (b) may be used.

Here, FIG. 8 shows a concrete example of a message in the format of FIG. 7A, FIG. 9 shows a concrete example of a message in the format of FIG. 7A ', and FIG.
The specific example of the message of the format of (b) is shown. "Fingerprint-Mod" in the header of each figure
“E: ...” corresponds to the identification information, and “Fingerprint-Type: ...” In the body portion of FIGS. 9 and 10 is FP.
In the method, “6E39 ... 0128” in the body part corresponds to the fingerprint.

FIG. 11 shows another example of the message format. (A) is a message when uncompressed,
(B) is a message at the time of compression. FIG. 11A shows
Data is placed in the body part in the same format as in FIG. 7A, but the message body is null in FIG. 11B. Further, FIG. 11B shows a calculation method of fingerprint (FP) in the header part,
The FP value is described. The normal header information and the identification information that makes it possible to identify the presence or absence of FP compression are the same as in the above example.

When not compressed, instead of FIG. 11 (a),
There is also a method of using the message format of FIG. 11 (a ') in which the header portion is provided with the FP method and the fingerprint.

If the client side proxy 40 knows the FP method used when transferring the message format, the message shown in FIG.
A message format (not shown) obtained by removing the FP method from the format may be used. Similarly, FIG.
A message format (not shown) obtained by removing the FP method from the message format of (b) may be used.

A specific example of the message in the format shown in FIG. 11A is the same as that shown in FIG. Also, FIG.
A specific example of the message in the format of 1 (b) is shown in FIG.
, And a specific example of the message in the format of FIG. 11 (a ') is shown in FIG.

In the following, a system configuration example that embodies the embodiment of the present invention described above will be described.

Web from client 50 to server 20
When the page is accessed, after the connection between the client 50 and the server 20 is established, roughly divided between the server 20 and the client 50, three processes are performed as shown in FIG.

First, between each device between the client 50 and the server 20 (here, between the client 50 and the client side proxy 40, the client side proxy 40-
Between the server-side proxy 30 and between the server-side proxy 30 and the server 20), initialization processing such as exchange of various information necessary for connection is performed.

Next, request message processing (hereinafter referred to as request processing) for requesting the content of the Web page from the client 50 to the server 20 is performed. In this request processing, a request message is transferred in one direction from the client 50 to the server 20.

In response to this request message,
A reply that transfers the requested Web page content from the server 20 to the client 50 in one direction.
Message processing is performed.

If each of the above processes is not successful, another process is performed (for example, reply
If the message processing is not successful, re-request message processing is performed), but since it is not directly related to the embodiment of the present invention, the description thereof will be omitted.

In the following, the points relating to the present invention between the server side proxy 30 and the client side proxy 40 will be described in detail by dividing into the above initialization processing, request processing and reply processing. In each process, except for between the server-side proxy 30 and the client-side proxy 40, there is no change (conventional) from each process that has been conventionally performed, and the description thereof will be omitted.

First, FIG. 15 to FIG. 15 will be used to describe a portion according to the embodiment of the present invention during initialization processing and request processing.
The functional blocks will be illustrated and described with reference to FIG.

In FIG. 15, the client side proxy 40 is provided with an FP list storage unit 71 for storing an FP method list showing the fingerprint calculation method owned by itself. This client side proxy 4
The FP method list of 0 is added with the FP method name when a new fingerprint calculation method is stored (installed) in the storage device (not shown) in the client side proxy 40 and stored in the storage device of the client side proxy 40. When deleting (uninstalling) the existing fingerprint calculation method, the FP method name is also deleted.

Similarly, the server-side proxy 30 also has an FP list storage unit 75 for storing an FP method list in which the fingerprint calculation method owned by itself is stored. The FP method list of this server-side proxy 30 is also stored (installed) in a storage device (not shown) in which a new fingerprint calculation method for the server-side proxy 30 is stored.
The FP method name is added when this is performed, and the FP method name is also deleted when the fingerprint calculation method stored in the storage device of the server-side proxy 30 is deleted (uninstalled).

During initialization processing, the server side proxy 30
Between the client side proxy 40 and the client-side proxy 40, a fingerprint calculation method is agreed upon when a new message is fingerprinted when the reply message is transferred during the main connection.

In FIG. 15, first, the FP method list of the client side proxy 40 is read from the FP list storage section 71 of the client side proxy 40, and the transmission section 72 is used.
Is transmitted to the server side proxy 30. The server side proxy 30 is the FP of this client side proxy 40.
The receiving unit 73 receives the method list, and the FP method determining unit 74 receives the method list.
Supply to. Further, the FP method storage unit 75 supplies the FP method list of the server-side proxy 30 to the FP method determination unit 74.

The FP method deciding unit 74 is provided with the FP method list of the server side proxy 30 and the client side proxy 40.
From the FP method list of No. 1, one fingerprint calculation method name that matches both is selected. In this selection, for example, each FP method in the FP method list 72 held by the client side proxy 40 is given a priority in advance, and the one having the highest priority is selected from the selectable ones. You can do this. If there is no match between the two, "Null" which means none is selected.
Although one is selected here, a plurality of selections may be made by adding a priority.

The selected fingerprint calculation method name (including Null) is temporarily registered in the FP method registration unit 76. Further, the selected calculation method name is notified to the client side proxy 40 via the transmission unit 77.

Receiving unit 78 of client-side proxy 40
Temporarily registers (including Null) the selected calculation method in the FP method registration unit 79. This allows the client-side proxy 40 and the server-side proxy 30 to understand the fingerprint calculation method (or that there is no matching FP method) used during the main connection.

When the initialization process is completed, the request process is performed. The client-side proxy 40 receives the request message from the client 50 at the receiving unit 80, and directly receives the request message from the transmitting unit 81.
Transfer to 0. The server-side proxy 30 receives the transferred request message at the receiving unit 82 and transfers the request message to the server 20 via the transmitting unit 83 as it is. The request processing shown here is equivalent to the processing in the conventional configuration.

Note that, for convenience, the receiving section 73 and the receiving section 82 of the server side proxy 30 are described as different blocks, but it goes without saying that they may be configured by the same block. Furthermore, although the transmitting unit 77 and the transmitting unit 83 of the server-side proxy 30 are also described in different blocks, it goes without saying that they may be configured by the same block. The same applies to the receiving units 78 and 80 and the transmitting units 72 and 81 of the client-side proxy 40.

FIG. 16 shows a portion relating to the embodiment of the present invention at the time of initialization processing and request processing.
5 shows another example different from No. 5.

In the initialization processing of FIG. 16, compared with the initialization processing of FIG. 15, the server side proxy 30 uses the determined fingerprint calculation method name as the server side proxy 30.
It is different in that it is not temporarily registered in. Instead, at the time of request processing, the client side proxy 40 reads the FP method name determined and registered at the time of initialization processing from the FP method registration unit 79, and adds this FP method name to the request message from the client 50. An FP system addition unit 84 is newly provided. The request message to which the FP method name is added by the FP method adding unit 84 is
The FP method separating unit 85 newly added to the server-side proxy 30 separates the FP method name. The separated FP method name is temporarily registered in the FP method registration unit 76 of the server-side proxy 30 as in FIG.

In the case of FIG. 16, the server side proxy 30 becomes aware of the determined fingerprint calculation method only after the request processing is performed. Also, if there is no FP method that agrees with both, N
The handling as “ull” is the same as the description of FIG. Further, although one FP method name is selected, a plurality of FP method names may be selected by adding a priority as in the description of FIG.

FIG. 17 shows a portion according to the embodiment of the present invention at the time of initialization processing and request processing.
17 shows yet another example different from FIG. 5 and FIG. 16.

The initialization process of FIG. 17 is different from the initialization process of FIG. 15 in that the server side proxy 30 does not transmit the determined fingerprint calculation method name to the client side proxy 40 (and registration). The difference). There is no change in request processing.
If there is no FP method that matches with both, Nul
Handling as l is the same as in FIG. Further, although one FP method name is selected, a plurality of FP method names may be selected by adding a priority as in the description of FIG.

In the case of FIG. 17, even if the request processing is completed, the client side proxy 40 does not know the determined fingerprint calculation method name. The fingerprint calculation is performed at the time of reply processing, which will be described later, so it is sufficient to know it by the time of the calculation.

15 to 17, the FP method is determined by the server-side proxy 30 in all cases, but the opposite is true, and the FP method list of the server-side proxy 30 is transmitted to the client-side proxy 40. However, it goes without saying that the client side proxy 30 may determine the FP method.

FIG. 18 shows the above-described FIGS.
As described above, another embodiment is shown in which the fingerprint calculation method to be used in particular is not determined during the initialization processing.

In FIG. 18, the initialization process is performed only for the subsequent request and the user authentication process which is the preprocess of the reply process, and therefore no process is shown.

The server-side proxy 30 and the client-side proxy 40 are respectively provided with FP list storage units 71 and 75 for storing the FP method list in which the fingerprint calculation method owned by each server is shown. The addition and deletion of this FP method list may be the same as the above-mentioned method.

At the time of request processing, the client side proxy 40 receives the request message from the client 50 at the receiving unit 80. The client side proxy 40 is stored in the FP list storage unit 75,
From the FP method list of its own, select one fingerprint calculation method name by a predetermined method, and select the FP method registration unit 7
9 and the FP method addition unit 84
This temporarily registered FP method name is read and added to the received request message. For this selection, for example, each FP method in the FP method list held by the client side proxy 40 itself is given a priority in advance, and the one having the highest priority may be selected.

The request message to which the method name of FP calculation is added is separated by the FP method separating unit 85 of the server side proxy 30. The separated FP method name is checked whether or not there is a match from the FP method list in which the name of the FP method included in the server-side proxy 30 is included in the FP list storage unit 71 of the server-side proxy 30. . If there is a match, the FP method name is temporarily registered in the FP method registration unit 76. on the other hand,
If there is no match, it is treated as Null and F
Information indicating that there is no registration or no registration is temporarily registered in the P system registration unit 76. Further, in this embodiment, one FP system name is selected, but a plurality of FP system names may be selected by adding a priority as in the description of FIG.

The server side proxy 40 transfers the separated request message to the server 20 via the transmitting unit 83.

Next, the reply message processing will be described with reference to FIGS.

First, the server side proxy 30 sets the server 20
The case of receiving a reply message from is described.

As shown in FIG. 19, the server-side proxy 30 receives the transfer message from the LAN 12 in the server center or the wide area network 14, and a receiving unit 131 for processing the data included in the transfer message. The processing unit 132 for performing the FP compression, the transmission unit 13 for performing the processing for transmitting the transfer message to the LAN 12 in the server center or the wide area network 14.
3. A fingerprint cache (FP cache) 134 for storing the fingerprint and the data that is the basis of the fingerprint in association with each other, and the FP that temporarily registered the FP method name during the initialization processing and the request processing described above.
A method registration unit 76 is provided. Further, the processing unit 132 refers to the fingerprint (FP) compression determination unit 135 and the FP method registration unit 76 for determining whether or not the data included in the transfer message should be the compression target, and which calculation method is used for the fingerprint. FP method determination unit 136 that determines whether to calculate a print, fingerprint cache 134
Fingerprint cache (FP cache) management unit 137 for performing search and registration with respect to, and fingerprint (FP) compression processing unit 139 for performing processing such as replacing data included in a transfer message with a corresponding fingerprint. including. In addition, the initialization process and the request process described above are performed in FIGS.
In the case of, in the reply processing, the FP method addition unit 1 for further adding the FP method used for the calculation of the FP to the message.
38.

FIG. 20 shows an example of the processing procedure of the server side proxy 30 when transferring the reply message from the server side proxy 30 to the client side proxy 40.
Note that FIG. 20 describes the processing when one reply message is received, but in reality, the server-side proxy 3
0 for all reply messages received by 0
The process illustrated in 0 is performed.

The server side proxy 30 receives the reply message from the server 20 by the receiver 131 (step S1).

The FP compression determination unit 135 checks and determines whether or not the reply data of the reply message is for FP compression (step S2). When it is determined that the reply data is not the object of FP compression (step S2), the received reply message is transferred from the transmission unit 133 to the client side proxy 40 (step S).
12).

If it is determined in step S2 that the reply data of the reply message is for FP compression, the FP method determination unit 136 causes the FP method registration unit 76.
(Step S3), the FP method of the FP method name temporarily registered is determined as the FP method to be used (step S4). Next, in the FP cache management unit 137,
The fingerprint value of the reply data is calculated using the FP method determined in step S4 (step S
5) The fingerprint cache 34 is searched by using the fingerprint value and the calculation method as a key (step S6).

Then, if the set of the fingerprint value and the corresponding data is registered in the fingerprint cache 134 (step S7),
The FP compression processing unit 139 converts the received reply message into a format for FP compression using the fingerprint value, and transmits it from the transmission unit 133 to the client side proxy 40 (step S9). When the initialization process and the request process described above are in FIG. 17 or 18, the FP method determined by the FP method determining unit 136 is added to the message in step S9. It is necessary (step S8).
If the FP method determined by the FP method determining unit 136 is different from the FP method stored in the cache,
The FP method to be added to the message is determined by a method such as (1) recalculating the FP again with the FP method determined by the FP method determining unit 136, or (2) using the FP method stored in the cache. The format in this case is
For example, FIG. 7B and the like. It should be noted that this step S8 may be performed even when the initialization process and the request process described above are performed in FIGS. 15 and 16.

In step S9, if necessary, a field (C
the value of the ontent-Length: field) is F
Set according to the P compression format.

On the other hand, as a result of the search in step S6, if the pair of the fingerprint value and the corresponding data is not registered in the fingerprint cache 134 (step S7), the following two operations are performed. I do.

(1) The FP compression processing unit 139 converts the received reply message into a format for non-FP compression (using the fingerprint value and the calculation method as necessary) (see, for example, FIG. a) and the like), the transmission unit 133
To the client-side proxy 40 (step S10).

(2) In the FP cache management unit 137,
The fingerprint value, the calculation method, and the reply data are associated with each other (using the fingerprint value as a key) and registered in the fingerprint cache 134 (step S11).

Any of the above (1) and (2) may be performed first, or may be performed in parallel.

As shown in FIG. 21, the present client-side proxy 40 has a receiving unit 141 which performs processing for receiving a transfer message from the LAN 16 in the user office or the wide area network 14, and the data included in the transfer message. A processing unit 142 for performing FP decompression,
LAN 16 in user office or wide area network 1
4 is provided with a transmission unit 143 that performs processing for transmitting a transfer message to the No. 4, and a fingerprint cache (FP cache) 144 that stores the fingerprint and the data that is the source of the fingerprint in association with each other. The processing unit 142 also includes a fingerprint (FP) compression determination unit 145 and an FP method registration unit 79 for determining whether or not the data included in the transfer message should be compressed and whether or not the FP compression of the transfer message is performed. FP method determination unit 146 that determines the FP compression method by referring to the FP method name temporarily stored by
Fingerprint cache (FP cache) management unit 147 for searching and registering in the cache 144, fingerprint for performing processing such as decompressing original data from the fingerprint included in the FP-compressed transfer message The (FP) decompression processing unit 148 is included. When the initialization process and the request process described above are in FIG. 17, the FP system registration unit 79 does not exist (or is not temporarily registered), so the FP system determination unit 146 analyzes the reply message, It is assumed that the FP method is determined by referring to the FP method included in the message. Also in the case of FIG.
Since the FP method is registered in the FP method registration unit 79 without checking whether or not the FP method is supported by the server-side proxy 30, the FP method determination unit 146 analyzes the reply message and F included in
It is better to refer to the P method and to confirm the FP method.

Next, FIG. 22 shows an example of the processing procedure of the client side proxy 40 when transferring the reply message from the server side proxy 30 to the client side proxy 40. Note that although FIG. 21 describes the processing when one request message is received, the processing illustrated in FIG. 22 is actually performed for all the request messages received by the client side proxy 40.

The client side proxy 40 includes the receiving unit 1
41 receives the reply message from the server-side proxy 30 (step S21).

The FP compression judgment unit 145 examines and judges whether or not the reply data of the reply message is for FP compression (step S22). When it is determined that the reply data is not the object of FP compression (step S22), the received reply message is transmitted by the transmission unit 14
3 to the client 50 (step S3)
1).

If the reply data of the reply message is judged to be the object of FP compression in step S22, the FP compression judgment unit 145 further checks whether or not the reply data is FP compressed and judges. Yes (step S23).

If it is determined in step S23 that the reply data of the reply message is FP-compressed (for example, in the case of FIG. 7B), the FP temporarily stored in the FP method registration unit 76. From the method name, use F
The P method is determined (S24). If the initialization process and the request process described above are performed in step S24 in FIGS. 17 and 18, the FP method to be used is determined from the FP method name included in the reply message (step S24). Also in the case of FIG. 18, step S2
The reason for performing No. 4 is to enable processing even when the server-side proxy 30 does not support the FP method selected from the client-side proxy 40.

Next, in the FP cache management unit 147,
The fingerprint value of the reply data is obtained by the FP method determined in step S24 (step S25),
The fingerprint cache 144 is searched using the fingerprint value and the calculation method as a key (step S26).

Then, the FP decompression processing unit 148 adds data corresponding to the value of the fingerprint retrieved from the fingerprint cache 144 to the received reply message and uses special information between the proxies. If so, the information is deleted and then transmitted from the transmitter 43 to the client 50 (step S2).
7). At this time, if necessary, a field (Content-Length) indicating the data length in the reply header.
The value of h: field) is set to the length of the data corresponding to the value of the fingerprint.

On the other hand, if it is determined in step S23 that the reply data of the reply message is not FP-compressed (for example, in the case of FIG. 7A), the following two operations are performed.

(1) When special information is used between the proxies in the FP decompression processing unit 148, this information is deleted from the received reply message, and then this is transmitted by the transmission unit 143.
To the client 50 (step S29).

(2) In the FP cache management unit 147,
The fingerprint value and the calculation method of the reply data are obtained (step S28), the fingerprint value and the reply data are associated with each other (using the fingerprint value and the calculation method as a key), and the fingerprint Register in the cache 144 (step S30).

Either of the above (1) and (2) may be performed first, or may be performed in parallel.

As described above, the probability that fingerprint values obtained from two different data items match is small enough to be ignored in practice, but if the fingerprint values obtained from two different data items match. It is also possible to solve this problem by calculating the fingerprint with another fingerprint calculation method using the method of the present invention.

In the following, FIG.
While compressing) and FIG. 24 (when compressing FP),
The data transfer using the fingerprint cache will be described more specifically. Note that, as a prerequisite, the server-side proxy 30 and the client-side proxy 40 will be described as the system of FIG. 15 in which the FP method is temporarily registered during initialization processing.

First, with reference to FIG. 23, an operation in the case where data not registered in the fingerprint cache is transferred from the server side proxy 30 to the client side proxy 40 and the fingerprint cache is registered will be described.

(1) The browser or the like on the client 50 uses the URL "/A.cgi", for example, as the server 20.
Then, it is assumed that a POST method request message is issued. A browser or the like is set in advance so that a request message to the server 20 is sent to the client side proxy 40.

(2) The client side proxy 40, which has received the request message from the client 50,
The request message is transferred to the server side proxy 30.

(3) The server side proxy 30 having received the request message transfers the request message to the server 50.

(4) The server 20 processes the request message, and then, the server side proxy 30
The reply message is sent back to.

(5) Upon receiving the reply message, the server-side proxy 30 first calculates the fingerprint using the fingerprint method determined during the initialization process for the reply data included in the received reply message, and then calculates the fingerprint. It is checked whether the data having the fingerprint name is stored in the fingerprint cache 34. If it does not exist, the first data (if the fingerprint cache is registered and then deleted or invalidated in some cases, fingerprint fingerprint is registered but deleted or invalidated, Since it is the first time thereafter), the data is stored (registered) in the fingerprint cache 34 with the fingerprint as a name.

(6) The server side proxy 30 transfers the reply message to the client side proxy 40.

As described above, if the fingerprint value calculated from the reply data is sent in the reply header or the like, the client side proxy 40 can save the trouble of calculating the fingerprint again.

(7) Since the client side proxy 40 which has received the reply message is the first data, the fingerprint method name in which the reply data is temporarily registered or put in the reply header or the like is taken out, and the fingerprint is also printed. -Register in the cache 44. As described above, the fingerprint is calculated from the reply data, or the fingerprint put in the reply header or the like by the server-side proxy is taken out and put in as the name.

(8) The client side proxy 40
(In the case of a configuration in which information used only between the server-side proxy 30 and the client-side proxy 40 such as the fingerprint value in the reply header exists, after deleting this), the reply message is sent to the client. Send back to 50 (browser running on the above).

In the server side proxy 30, the fingerprint cache registration of (5) above is performed by
It may be performed after the operation of (6). Further, in the client side proxy 40, the fingerprint cache registration of (7) may be performed after the operation of (8).

Next, with reference to FIG. 24, the operation in the case where the operation shown in FIG. 23 is performed and the cached data is transferred from the server side proxy 30 to the client side proxy 40 will be described.

(1) to (4) are the same as (1) to (4) in the operation described with reference to FIG.

(5) Upon receiving the reply message from the server 50, the server side proxy 40 first calculates the fingerprint of the reply data of the received reply message by the FP method already determined at the time of connection, and the FP method and finger It is checked whether the data having the print name is stored in the fingerprint cache 34. If it is, it is the data that has been sent in the past (data that has been registered in the fingerprint cache), so (for example, enter the fingerprint value in the reply header and empty the reply body as described above. Replace the data in the reply body with the fingerprint.

(6) The server side proxy 30 transfers the reply message in which the reply body is replaced with the fingerprint to the client side proxy 40.

(7) Upon receiving the reply message, the client side proxy 40 detects that the reply data is replaced with the fingerprint, and the specified fingerprint (for example, in the reply header or the like as described above) is set. It is used to retrieve the corresponding data from the fingerprint cache 44 and place it in the reply body.

(8) Then, the client side proxy 3
0 is (server side proxy 30 and client side proxy 4 such as fingerprint value in reply header)
In the case of a structure in which information used only between 0 and 0 exists, after deleting this, a reply message is sent back to the client (browser running on the above).

By the way, since the fingerprint caches of the server-side proxy 30 and the client-side proxy 40 have an upper limit in capacity, garbage collection is performed according to a predetermined algorithm to erase, for example, old data or data that is unlikely to be used. It is preferable to go.

However, in this case, the fingerprint cache 34 of the server side proxy 30 may have data which has already been deleted in the fingerprint cache 44 of the client side proxy 40. Therefore, in (7) above, the client-side proxy 40 tried to retrieve the data that should replace the reply data from the fingerprint cache 44 based on the fingerprint. The print / data pair may not exist. In such a case, for example, the client side proxy 40 requests the server side proxy 30 to send the data of the designated fingerprint,
The requested server-side proxy 30 may be provided with a mechanism for fetching the specified fingerprint data from the fingerprint cache 34 and sending it back.

On the contrary, when the fingerprint cache 34 of the server side proxy 30 has already erased it, but the fingerprint cache 44 of the client side proxy 40 still has the data, At (7) in the operation described with reference to FIG. 23, when the fingerprint / reply data is registered in the fingerprint cache 44 in the client-side proxy 40, the fingerprint / reply data registered at that time. May be overwritten.

At (5) in the operation described with reference to FIG. 24, the server side proxy 30 obtains the fingerprint of the reply data, and if the fingerprint is in the fingerprint cache 34, the reply data is obtained. The same data as is paired with the fingerprint and the fingerprint cache 3
It is treated as if it is in No. 4. In practice,
This method is sufficient, provided that the different fingerprints do not produce the same fingerprint, but with a very small probability to eliminate the error that would occur if the fingerprints of the different data happen to have the same value. There is also a way to In this case, when the fingerprint obtained from the reply data is in the fingerprint cache 34, the fingerprint cache 3 is paired with the fingerprint cache 34.
The data stored in 4 and the ply data may be compared to determine whether they are the same. At this time, if it is determined that data with the same fingerprint but different contents is registered,
The following methods are possible. -The fingerprint is no longer used (the data giving the fingerprint will not be cached anymore). Prioritize previously registered fingerprints / data (other data that gives a fingerprint with the same value as the fingerprint being registered will not be cached during that registration). Priority is given to the fingerprint / data currently being registered (the fingerprint / data being registered will be updated one after another by other data giving the fingerprint of the same value). • Compress and use another fingerprinting scheme (especially useful if multiple prioritized fingerprints are selected for availability).

As described above in detail, in the present embodiment, data, compressed data thereof, and the name of the method of generating the compressed data are held in association with each other between the data transfer devices,
Regarding the data that holds these correspondences, by transferring the compressed data and the method name instead of transferring the data, even when the method version is upgraded or a plurality of method names are mixed, The amount of transfer data between the data transfer devices can be reduced.

The server-side proxy 30 of this embodiment is also used.
Alternatively, the client side proxy 40 is provided with a correspondence table (URL / FP table) between the URL and the fingerprint, and by using this together with the fingerprint cache, the shared cache operation of the proxy server is also performed. It is also possible.

Each of the above functions can be realized as software.

Further, this embodiment is implemented as a program for causing a computer to execute a predetermined means (or for causing a computer to function as a predetermined means or for causing a computer to realize a predetermined function). It can also be implemented as a computer-readable recording medium recording the program.

Note that the configurations illustrated in the embodiments of the present invention are examples, and the present invention is not intended to exclude other configurations, and some of the illustrated configurations may be replaced with other configurations or illustrated. Other configurations that are obtained by omitting a part of the configuration, adding another function or element to the exemplified configuration, or combining them are possible. Also, another configuration logically equivalent to the exemplified configuration,
Other configurations including a portion logically equivalent to the exemplified configuration, another configuration logically equivalent to the main part of the exemplified configuration, and the like are possible. Further, another configuration that achieves the same or similar purpose as the exemplified configuration, another configuration that achieves the same or similar effect as the exemplified configuration, and the like are possible.

The various variations of the various constituent parts exemplified in the embodiments of the present invention can be implemented in an appropriate combination.

The embodiment of the present invention is an invention as an individual device, an invention as to two or more related devices, an invention as an entire system, an invention as to a component inside an individual device, or corresponding to them. The invention of various methods, steps, concepts, or categories, such as the invention of the method, is included or included.

Therefore, from the contents disclosed in the embodiments of the present invention, the invention can be extracted without being limited to the exemplified configuration.

The present invention is not limited to the above-described embodiments, but can be implemented with various modifications within the technical scope thereof.

[0142]

According to the present invention, the data, the compressed data thereof, and the name of the method by which the compressed data is generated are held in correspondence between the data transfer devices, and the data holding the correspondence is By transferring the compressed data and the method name instead of transferring the data, even when the method version is upgraded or a plurality of method names are mixed,
The amount of transfer data between the data transfer devices can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a conventional computer network system.

FIG. 2 is a diagram showing a configuration example of a computer network system according to an embodiment of the present invention.

FIG. 3 is a diagram showing another configuration example of the computer network system according to the embodiment.

FIG. 4 is a diagram showing still another configuration example of the computer network system according to the embodiment.

FIG. 5 is a view for explaining a fingerprint used in the same embodiment.

FIG. 6 is a diagram for explaining a fingerprint cache used in the same embodiment.

FIG. 7 is a diagram showing an example of a message format used in the same embodiment.

FIG. 8 is a diagram showing a specific example of a message in the format of FIG. 7 (a).

FIG. 9 is a diagram showing a specific example of a message in the format of FIG. 7 (b).

FIG. 10 is a diagram showing a specific example of a message in the format of FIG. 7 (a ').

FIG. 11 is a diagram showing another example of a message format used in the same embodiment.

FIG. 12 is a diagram showing a specific example of a message in the format of FIG. 11 (b).

FIG. 13 is a diagram showing a specific example of a message in the format of FIG. 11 (a ').

FIG. 14 is a diagram showing three processes according to the same embodiment.

FIG. 15 is a functional block diagram related to initialization processing and request processing according to the same embodiment.

FIG. 16 is another functional block diagram relating to the initialization processing and the request processing according to the embodiment.

FIG. 17 is still another functional block diagram relating to the initialization process and the request process according to the embodiment.

FIG. 18 is yet another functional block diagram relating to initialization processing and request processing according to the same embodiment.

FIG. 19 is a functional block diagram of the server-side proxy 30 at the time of reply according to the embodiment.

FIG. 20 is a view showing an operation procedure of the server side proxy 30 at the time of reply according to the embodiment.

FIG. 21 is a functional block diagram of the client side proxy 40 at the time of reply according to the embodiment.

FIG. 22 is a view showing an operation procedure of the client side proxy 40 at the time of reply according to the embodiment.

FIG. 23 is a view for explaining data transfer between the server side proxy 30 and the client side proxy 40 according to the same embodiment.

FIG. 24 is a view for explaining data transfer between the server side proxy 30 and the client side proxy 40 according to the same embodiment.

[Explanation of symbols]

2 ... ASP server center 4 ... User office 12 ... ASP server center LAN 14 ... WAN 16 ... User office LAN 20 ... Server device 30 ... Server side proxy device 40 ... Client side proxy device 50 ... Client device 71 ... FP list storage Units 72, 77, 81, 83, 133, 143 ... Sending units 73, 78, 80, 82, 131, 141 ... Receiving unit 74 ... FP system determining unit 75 ... FP list storage unit 76, 79 ... FP system registering unit 84 FP method adding unit 85 FP method separating units 132 and 142 Processing units 134 and 144 Fingerprint caches 135 and 145 FP compression determining units 136 and 146 FP method determining units 137 and 147 Fingerprint cache management Unit 138 ... FP system addition unit 139 ... FP compression processing unit 148 ... FP decompression processing unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Yoshida             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Shunbun             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Kenichiro Yoshii             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Takayuki Miyazawa             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Yasuhiro Kimura             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Haruhiko Toyama             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center F-term (reference) 5B082 GA01 HA02 HA05 HA08

Claims (7)

[Claims] 1. A first data transfer device including a plurality of calculation methods for compressing data and a second data transfer device including a plurality of calculation methods for compressing data are connected via a communication path. By making a data request from the first data transfer device to the second data transfer device,
A data transfer method capable of acquiring data requested by the first data transfer apparatus, wherein both data are selected from a plurality of calculation methods included in the first data transfer apparatus and a plurality of calculation methods included in the second data transfer apparatus. The one calculation method provided in the transfer device is determined, the second data transfer device acquires data corresponding to the data request from the first data transfer device, and compresses this data by the determined one calculation method. It is confirmed whether or not the data compressed by the one calculation method is already stored in the storage device provided in the second data transfer device, and if the confirmation result is not stored, the data and the data are stored in the storage device. The compressed data and the one calculation method are stored in association with each other, the data is transferred to the first data transfer device, and if the confirmation result is already stored, the compressed data is stored as the first data. Transfer to transfer device Data transfer method is characterized in that so as to. 2. The determination of the one calculation method is performed by the first data transfer device receiving identification information indicating each of a plurality of calculation methods provided in the second data transfer device from the second data transfer device. , One of the identification information indicating each of the plurality of calculation methods provided in the first data transfer device is determined, and the determined identification information is transmitted to the second data transfer device. The data transfer method according to claim 1, wherein: 3. The transmission of the determined identification information to the second data transfer device is performed by adding it to a request message from the first data transfer device to the second data transfer device. The data transfer method according to claim 2, wherein 4. A data transfer device comprising: a compression unit capable of compressing data by each of a plurality of calculation methods; and a storage unit that stores in advance identification information indicating the plurality of calculation methods.
A data transfer method for performing data transfer with another data transfer device via one communication path, wherein identification information indicating a plurality of calculation methods of the other data transfer device is received from the communication path, From the identification information of the plurality of calculation methods stored in the storage unit and the received identification information of the plurality of calculation methods, one of the identification information of the matching calculation methods is selected, and the calculation method indicated by the identification information is selected. Is transmitted as the calculation method utilizing the above, and the identification information of the determined calculation method is transmitted to the first communication path, and the data or the data is processed by the determined calculation method from the first communication path. When the compressed data is received and the received data is the data, the compression means compresses the data according to the determined calculation method, and the calculation method is associated with the compressed data and the data. Data transfer If the received data is compressed data, the corresponding data is acquired from the cache means based on the determined calculation method and the processed data, A data transfer method characterized in that data received from a communication channel or the acquired data is transmitted to a second communication channel. 5. A compression means capable of compressing data by each of a plurality of calculation methods, a storage means for storing identification information indicating the plurality of calculation methods in advance, and a plurality of calculations from an external first communication path. The first receiving means for receiving identification information indicating the method, the identification information of the plurality of calculation methods stored in the storage means, and the identification information of the plurality of calculation methods received by the first receiving means Selecting one of the identification information of the calculation method to be determined and deciding as a calculation method using the calculation method indicated by the identification information; and temporarily identifying information of the calculation method determined by the calculation method determining means. Registration means for registering, first sending means for sending the identification information of the calculation method determined by the calculation method determining means to the first communication path, and data or the data for sending the data from the first communication path Or send Second receiving means for receiving the compressed data processed by the calculation method indicated by the identification information, and when the second receiving means receives the data, the second receiving means receives the data according to the calculation method determined by the calculation method determining means. When the data is compressed by the compression means, the calculation method, the compressed data compressed, and the cache means that stores the data in association with each other; and the reception by the second reception means is compressed data,
Acquisition means for acquiring corresponding data from the cache means based on the calculation method indicated by the identification information temporarily registered in the registration means and the compressed data; and data received from a first communication path or the acquisition A second transfer means for transmitting the data acquired by the means to the second communication path. 6. The data request is received from the first communication path, and the second request is received.
A data transfer device that transfers the data request to another data transfer device connected via a communication path, acquires data corresponding to the data request, and sends the data to the first communication path. Compression means capable of compressing data by each of the calculation methods, storage means for storing in advance identification information indicating the plurality of calculation methods, and identification information indicating a plurality of calculation methods from an external first communication path. Identification information of a matching calculation method from first receiving means for receiving, identification information of a plurality of calculation methods stored in the storage means, and identification information of a plurality of calculation methods received by the first receiving means And a registration means for temporarily registering the identification information of the calculation method determined by the calculation method determination means; The total In response to a data request to the first transmission means for transmitting the identification information of the calculation method determined by the calculation method determination means to the first communication path, and to the other data transfer device, this request is sent from the first communication path. Second receiving means for receiving data or compressed data processed by the calculation method indicated by the identification information that sent the data from the sending means, and when the second receiving means receives the data A cache unit that compresses the data by the compression unit according to the calculation method determined by the calculation method determination unit, and stores the calculation method and the compressed data compressed and the data in association with each other; When the receiving means receives compressed data,
Acquisition means for acquiring corresponding data from the cache means based on the calculation method indicated by the identification information temporarily registered in the registration means and the compressed data; and data received from a first communication path or the acquisition A second transfer means for transmitting the data acquired by the means to the second communication path. 7. A program for causing a computer to function as a data transfer device, comprising: a plurality of calculation methods; storage means for storing identification information indicating the plurality of calculation methods in a storage unit of the computer in advance; First receiving means for receiving identification information indicating a plurality of calculation methods from an external first communication path; and identification information of the plurality of calculation methods stored in the storage unit,
A calculation method for selecting one of the identification information of the matching calculation method from the identification information of the plurality of calculation methods received by the first receiving means, and determining the calculation method indicated by the identification information as the calculation method. Determination means, registration means for temporarily registering the identification information of the calculation method determined by the calculation method determination means in the storage unit, and identification information of the calculation method determined by the calculation method determination means for the first communication path First transmitting means for transmitting to the first communication path, second receiving means for receiving data or compressed data processed by the calculation method indicated by the identification information transmitted from the transmitting means from the first communication path; 2 When the reception means receives data, the calculation method corresponding to the identification information registered in the registration means is read from the storage unit, the data is compressed, and the identification information of the calculation method and the compressed information are compressed. Pressure Compressed data and a cache unit that stores the data in association with each other in the storage unit; and when the second receiving unit receives the compressed data,
An acquisition unit for acquiring corresponding data from the storage unit based on the calculation method indicated by the identification information temporarily registered in the storage unit and the compressed data; and data received from a first communication path or the acquisition A program for causing a computer to realize second transmission means for transmitting the data acquired by the means to the second communication path.