JP4157585B2 - Server side proxy device, client side proxy device, data transfer method and program - Google Patents

Description

  The present invention relates to a server-side proxy device, a client-side proxy device, a data transfer method, and a program that perform data transfer for other devices.

  2. Description of the Related Art A client / server type information system is widely used, which includes a server that provides various services via a network and a client that requests a desired service from the server. In particular, the WORLD WIDE WEB system (or simply referred to as WEB) composed of a WEB server and a client that communicate using the HTTP protocol on the Internet is a client-server type information system that is very widely used. Normally, a server program operates on the server, and a predetermined tool (program) such as a browser operates on the client. The contents of services provided on the Internet are also diverse, providing information such as text, still images, moving images, audio (such as homepages, e-mails, digital contents, etc.) and programs via the network. Various services such as distribution or transfer services, electronic store services for selling products, reservation services for seats and rooms, mediation services for various contracts, etc., and new forms of services one after another Has appeared.

  By the way, in a client-server type information system such as WEB, whatever service is provided, the service is basically provided by data transfer between the client and the server. Is done. Therefore, the capacity (bandwidth) of the network used for communication between the client and the server tends to become a bottleneck of the entire system. Therefore, a cache technique is usually used to reduce the load on the network.

  In the case of a WEB system, browsers and the like that operate on a client often use a cache mechanism, and cache recently accessed data. In WEB, access is made by designating information or service with a name called URL, so that the cache on the client is the information that has been requested to the WEB server in the past and the data returned as a result of the service can be cached. The URL is recorded in the cache in association with the URL. In this case, if there is a request for the same URL information or service as that in the cache and it can be determined that the response data in the cache is not stale, by returning that data, Communication between can be eliminated.

  When there are a plurality of users in a corporate office LAN, a research institution LAN, or a home LAN, a proxy server may be placed between the LAN and the Internet, and a cache mechanism may be provided in the proxy server. Many. The cache in the client (for example, the browser cache) operates as a cache dedicated to the client user, while the proxy server cache on the LAN operates as a shared cache for a plurality of client users. For this reason, in the latter case, the cache is effective even when accessing a URL accessed by another person (another client) in the past.

  Now, in WEB, communication is performed between a client and a server using a protocol called HTTP. The HTTP protocol is a combination of a “request message” sent from the client to the server and a “reply message” that returns a response from the server to the client.

  The request message consists of a “request header” and a “request body”. The request header includes a URL for designating information to be accessed and a service, a method name indicating the type of access, and other various information necessary for access. The data to be sent to the server is entered in the request body. The data contained in the request body is also called “request data”.

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

  As a request message method, there are a “GET method” that reads information on the server, a “PUT method” that writes data held by the user to the server, and a “POST method” that sends back the result processed in response to the request. It is the main thing used to access services. In addition, a method such as DELETE is defined.

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

  Data read from the server by the GET method can be divided into “dynamic data” generated on the server side each time it is read, and “static data” that returns data already stored on the server side as it is. Of these, the contents of dynamic data may be different each time the same URL is read, and in many cases, the server sends back a specification indicating that caching is impossible in the header of the reply message. Therefore, it is a portion of static data that is subject to caching with WEB data. This static data can be divided into “shared data” that can be referenced by an unspecified number of users and “private data” that performs access control so that only specific users can access by authenticating users. . The former shared data can be cached in any cache. However, the latter private data cannot be cached in a shared cache such as a proxy server (because private data must be authenticated and sent back by the server). However, in the case of a personal cache such as a browser, even private data can be cached.

  Since the POST method returns the result of processing on the server side, in general, the server sends back the result with a specification indicating that caching is impossible in the header of the reply message. Therefore, it is not normally subject to caching.

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

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

However, as a system in which a user accesses information and services on a server via a network using a WEB browser, such as a WEB-based ASP (Application Service Provider), a conventional cache technology as described below. The data that cannot be handled is increasing.
-Since the user is authenticated and the user who can access is restricted, there is much private data.
-Many dynamic data are generated by referring to the backend database.
-In many cases, the POST method is used for form processing and search.
-The PUT method is often used to share information within a group.
As a result, the cache technology alone has not functioned effectively as a technique for reducing the load on the network.

  The present invention has been made in consideration of the above circumstances, and a server-side proxy device, a client-side proxy device having a cache technology / compression technology that can further reduce the load on the network connecting the data transfer devices, It is an object to provide a data transfer method and program.

  The present invention is a server-side proxy device that receives data transmitted from a server device and transmits the data to a client-side proxy device that communicates with the client device that is the destination, and receives the data from the server device Receiving means; fingerprint generating means for generating a fingerprint of data received by the receiving means; and the data received by the receiving means as reference data generated by the fingerprint generating means based on the reference data Holding means for holding the fingerprint in association with the reference data as a fingerprint cache; and the fingerprint generated by the fingerprint generating means based on data received by the receiving means is the fingerprint ·cache A first determination unit configured to determine whether the fingerprint is held; and the data received by the reception unit when the first determination unit determines that the fingerprint is not stored in the fingerprint cache. For one part or a plurality of parts, a fingerprint associated with reference data including the same content as the part of the reference data held in the fingerprint cache for each part, and In the reference data, compression information consisting of a pair of location information that can identify the location where the same content exists is obtained, and a portion corresponding to the compression information is obtained from the compression information and the data received by the receiving means. Differential compression processing means for generating differential compression expression data including direct designation information indicating the remaining excluded content; For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data A second determination unit that determines whether or not a value indicating the degree is equal to or greater than a reference value; and the fingerprint is held in the fingerprint cache when the reception unit receives the data If the first determination means determines that the fingerprint compression data including the fingerprint is used as the destination client device instead of the original data of the fingerprint as the client side proxy. Before sending to the device and the fingerprint is not held in the fingerprint cache When the first determination means determines, the second determination means determines that the value indicating the degree of compression of the differential compression expression data generated by the differential compression processing means is greater than or equal to the reference value. When the determination is made, the fingerprint and the data that is the source of the fingerprint are associated and added to the fingerprint cache, and the differential compression is used instead of the data that is the source of the differential compression expression data. Differential compression data including representation data is transmitted to the client side proxy device as the destination client device, and the differential compression representation data generated by the differential compression processing means has a value indicating the degree of compression. When the second determination means determines that the reference value is not greater than or equal to the reference value, the fingerprint and the source of the fingerprint Transmitting means for associating the received data with the fingerprint cache and transmitting the uncompressed data including the received data to the client-side proxy device as the destination client device. It is characterized by having.

The present invention is a client-side proxy device that receives data transmitted from a server device via a server-side proxy device, and transmits the data to a client device that is a destination thereof. A holding unit for holding a fingerprint of the reference data as a client side fingerprint cache in association with the reference data, and a fingerprint compression including the fingerprint of the data instead of the data from the server side proxy device Time data, instead of the data, for one part or a plurality of parts of the data, the fingerprint of the reference data specified for each part and including the same contents as the part, and the same in the reference data The location where the contents of Data at the time of differential compression including differential compression expression data including compression information consisting of a set of location information and direct designation information indicating the remaining contents excluding a portion corresponding to the compression information from the data, or the data Receiving means for receiving uncompressed data, and the data received by the receiving means is the fingerprint compressed data, the differential compressed data, or the uncompressed data When the type determination means determines that the type determination means and the reception means have received the differential compression time data, the differential compression expression data included in the differential compression time data includes With reference to a set of the fingerprint and the location information included in the compression information corresponding to the portion in the data that was the source of the differential compression expression data, Each, the client-side the fingerprint and the location information from the fingerprint cache obtains the same contents as the part based on a corresponding portion the same content as the acquired, the difference compressed representation data directly include When the type determination means determines that the restoration processing means for restoring the original data of the differential compression expression data using the designation information and the reception means has received the fingerprint compression data Transmits the data held in the client-side fingerprint cache in association with the fingerprint included in the compressed data to the client device as the destination, and the receiving means receives the differential compression data If the type determination means determines, the restoration processing means Data restored based on the differentially compressed representation data included in the data is added to the client-side fingerprint cache in association with the fingerprint generated based on the data, and the data is added to the destination When the type determining unit determines that the receiving unit has received the uncompressed data, the data included in the uncompressed data is generated based on the data. in association with the fingerprint in addition to the client-side fingerprint cache was, and, the data, e Bei and transmission means for transmitting to the said destination said client device, before Symbol server side proxy device, wherein Means for receiving the data from a server device; and a finger for the received data. Means for generating a print, as reference data to said data unit is received to the receiving, the fingerprint means has generated said generated based on the reference data, the server-side finger print in association with the reference data Means for holding as a cache and one or more parts of the received data if the fingerprint generated based on the received data is not held in the server-side fingerprint cache For each of the parts, among the reference data held in the server-side fingerprint cache, the fingerprint associated with the reference data including the same content as the part, and the same in the reference data The location where the content exists can be identified Differential compression including compression information, and direct designation information indicating the remaining contents excluding a portion corresponding to the compression information from the data received by the receiving unit Differential compression processing means for generating representation data, and the data amount of the differential compressed expression data generated by the differential compression processing means and the data amount of the data that was the source of the differential compressed expression data and the differential compressed expression data And a difference expression availability determination means for determining whether or not a value indicating the degree of compression calculated by the amount of data is equal to or greater than a reference value, and is generated based on the data when the data is received If the fingerprint is held in the server-side fingerprint cache, the fingerprint is used instead of the data that was the source of the fingerprint. When the fingerprint compression data including print is transmitted to the client side proxy device as the destination client device, and the fingerprint is not held in the server side fingerprint cache, the differential compression is performed. When the differential representation availability determination unit determines that the value indicating the degree of compression is greater than or equal to the reference value for the differential compression representation data generated by the processing unit, the fingerprint and the source of the fingerprint are the same. The data at the time of differential compression including the differential compression expression data instead of the data that was the source of the differential compression expression data becomes the destination. Send to the client side proxy device as addressed to the client device When the differential representation availability determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression representation data generated by the differential compression processing unit, the fingerprint and the fingerprint The original data is associated and added to the server-side fingerprint cache, and uncompressed data including the received data is transmitted to the client-side proxy device as the destination client device. characterized in der Rukoto having a unit.

  The present invention relating to the apparatus is also established as an invention relating to a method, and the present invention relating to a method is also established as an invention relating to an apparatus. Further, the present invention relating to an apparatus or a method has a function for causing a computer to execute a procedure corresponding to the invention (or for causing a computer to function as a means corresponding to the invention, or for a computer to have a function corresponding to the invention. It is also established as a program (for realizing) and also as a computer-readable recording medium on which the program is recorded.

  According to the present invention, the correspondence between the data and the fingerprint is maintained between the server side proxy device and the client side proxy device, and the data having this correspondence is handled instead of transferring the data. By transferring the fingerprint to be transferred, the amount of data transferred between the server side proxy device and the client side proxy device can be reduced.

  For example, even if the reply message of the GET method is private data, it can be compressed between fingerprints and transferred between proxy devices. Further, for example, even if the reply message of the GET method is dynamic data, if the content is the same, it can be compressed by a fingerprint and transferred between proxy devices. Further, for example, even in the case of the POST method, if the result is the same data, the data can be compressed between fingerprints and transferred between proxy devices.

  In addition, according to the present invention, since the fingerprint corresponding to the data is not held, even if the corresponding fingerprint cannot be transferred instead of transferring the data, By transferring the data expressed by compressing the data using the corresponding fingerprint, the amount of transfer data between the proxy devices can be reduced.

  For example, if the reply data of the GET method or the POST method is partially different from the previously accessed data, the data amount can be reduced by differential transfer. Also, for example, if the PUT method or POST method request data is partially different from the previously sent data, the amount of data can be reduced by differential transfer.

  According to the present invention, the correspondence between the data and the fingerprint is maintained between the server side proxy device and the client side proxy device, and the data having this correspondence is handled instead of transferring the data. By transferring the fingerprint to be transferred, the amount of data transferred between the server side proxy device and the client side proxy device can be reduced.

  Hereinafter, embodiments of the invention will be described with reference to the drawings.

  In the following, a case where the WAN is the Internet and the client is connected to the user office LAN and the HTTP protocol is used will be described as an example. Even if the client is installed in a home LAN other than the office, for example, it can be applied even if a protocol other than the HTTP protocol is used.

  FIG. 38 shows a basic configuration example of a computer network system to which the present invention is applied. In this configuration example, a wide area network (WAN) 214 such as the Internet or a dedicated line is connected between a local area network (LAN) 212 in the ASP server center 202 and a local area network (LAN) 216 in the user office 204. The server 220 in the ASP server center 202 and the client 250 in the user office 204 can communicate with each other via a LAN 212, a WAN 214, and a LAN 216. One or more servers are connected to the ASP server center LAN, and one or more clients are connected to the user office LAN.

  The WEB-based ASP provides services by various application programs from the server 220 installed in the server center 202 via the WAN 214, and the user uses a WEB browser on the client installed in the office 204. Access the service.

  In such a usage form, the effective communication capacity (bandwidth) of the network connecting the user office LAN 216 and the server center LAN 212, particularly the wide area network 214 such as the Internet, is the server center LAN 212 or the user office LAN 216. Lower than that, which becomes a bottleneck in performance, causing a communication delay, resulting in a problem that the response performance of the application is lowered.

  Therefore, in this embodiment, as shown in FIG. 1, two modules, a server-side proxy 230 and a client-side proxy 240, are installed at both ends of the wide area network 214 that connects the server center LAN 212 and the user office LAN 216. The bottleneck of the wide area network is eliminated by reducing the amount of communication data by performing fingerprint compression (FP compression) described later or differential compression described later between them.

  The server 220, the server-side proxy 230, the client-side proxy 240, and the client 250 of this embodiment all have software (server program, server-side proxy program, client-side proxy program, client program) on the computer. It can be realized by operating it. In this case, an OS having a desired function of the computer, driver software, software such as packet communication software, encryption software, etc., or hardware such as a communication interface device, an external storage device, and an input / output device is mounted or connected as necessary. Is done. In this case, it is preferable to use a graphical user interface (GUI) for inputting information from the user or the administrator or presenting information to the user.

  On the client 250 used by the user to use the service, a program such as a WEB browser operates according to the purpose. A user uses a service by, for example, issuing a request message to a server that provides a desired service such as information transfer or order reception from the WEB browser, receiving a reply message, or repeating this appropriately. . 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. Further, the client may be not a general-purpose computer but a mobile phone terminal having an Internet function, for example.

  A predetermined server program runs on the server 220 and provides a service specific to the server site to the user of the client 220.

  As shown in FIG. 1, the server-side proxy 230 can be implemented by connecting to both the intra-server center LAN 212 and the WAN 214 so as to operate as a transparent proxy. Moreover, as shown in FIG. 2, it can also be installed on the server center LAN 212. Further, as shown in FIG. 3, the function of the server side proxy 230 can be implemented in the server 220.

  Similarly, as shown in FIG. 1, the client-side proxy 240 is connected to both the intra-user office LAN 216 and the WAN 214, and can be installed and implemented so as to operate as a transparent proxy. In addition, as shown in FIG. 2, it can be installed on the user office LAN 216 and implemented. Further, as shown in FIG. 3, the function of the client side proxy 240 can be implemented in a browser or the like that operates on the client 250. Alternatively, the client-side proxy 240 for personal use may be operated on the client 250 such as a browser.

  Note that the server-side proxy 230 and the client-side proxy 240 may have the same form as shown in FIGS. 1 to 3 or different forms.

  Hereinafter, the fingerprint cache and FP compression using the fingerprint cache will be described, and then differential compression will be described.

  Both the server-side proxy 230 and the client-side proxy 240 of the present embodiment have a cache mechanism called a fingerprint cache (FP cache). The fingerprint cache records and manages data exchanged by the HTTP protocol by a name called a fingerprint (FP).

  As illustrated in FIG. 4, the fingerprint is determined by a predetermined calculation method (hash function in the example of FIG. 4) from the contents of data exchanged by the HTTP protocol (content in the example of FIG. 4). It ’s a short number. This numerical value may be a variable length, but a fixed-length numerical value is easier to handle from the viewpoint of ease of processing.

  As a method for calculating the fingerprint, a well-known hash function such as MD-5 or SHA-1 can be used. These hash functions are used for digital signatures on data, and when given data is converted into a 128-bit number for MD-5 and a 160-bit number for SHA-1. can do. The feature of these hash functions is that 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 However, when two different data A and B are given, the hash value calculated for data A and the hash value calculated for data B are different with a very high probability. (In principle, the hash values calculated for two different data A and B may be the same, but the probability is small enough to be ignored in practice).

  As shown in FIG. 5, the fingerprint cache (60 in the figure) of the server-side proxy 230 and the client-side proxy 240 has a data body (61 in the figure) exchanged in the past by the HTTP protocol. The fingerprint value (62 in the figure) calculated from the above is recorded and managed as a name.

  For example, when data is transferred from the server-side proxy 230 to the client-side proxy 240 using the HTTP protocol, the server-side proxy 230 calculates a fingerprint of the data, and the data corresponding to the fingerprint enters the fingerprint cache. If so, since the data (data having the same content) has been transferred in the past, the corresponding fingerprint value is transferred without transferring the data. The client-side proxy 240 that has received the fingerprint can reproduce the data to be transferred by extracting the data corresponding to the fingerprint value from the fingerprint cache. By using this method (ie, data compression-> data transfer-> data decompression), it is only necessary to send the fingerprint value if it is the same data that was sent in the past. Can do. Of course, the same applies when transferring data from the client-side proxy 240 to the server-side proxy 230.

  For explanation, when transferring data between the server-side proxy 230 and the client-side proxy 240, the fingerprint cache is used to replace the message body data with the fingerprint to compress the transfer information amount. This is called print compression (FP compression).

  It should be noted that between the server-side proxy 230 and the client-side proxy 240, an object to which FP compression is applied to all messages (that is, an object for performing processing for replacing data with a fingerprint using a fingerprint cache). However, for example, in order to exclude the application to a message that cannot be expected to have a fingerprint cache effect, a message that satisfies a predetermined condition is excluded from the application target of FP compression (always FP compression). May be transferred). The predetermined condition in this case is, for example, that predetermined information is described in the message header. Specifically, for example, information indicating a GET method and information indicating a request are described in a message header. Another example of the predetermined condition is that the data to be transferred is null or has a very short size. Of course, there are various other variations. A plurality of conditions may be used in combination.

  Subsequently, differential compression will be described.

  In the above-mentioned FP compression, the identity of the data is judged at high speed using the fingerprint for the data, and the same data as the data registered in the fingerprint cache is not transferred between the proxies (instead of the data) Reduce the load on the network).

  However, FP compression cannot be applied to data that is different from data registered in the fingerprint cache, even if most of the data has the same contents. Therefore, in this embodiment, even when FP compression is not possible, one or more data registered in the fingerprint cache is used as reference data to transfer the reference data fingerprint, difference information for the reference data, or the like. By expressing transfer data with information for restoring power data, the transfer data is expressed with a small amount of information, and the transfer data amount is reduced as much as possible. In other words, the basic idea is to use the data in the fingerprint cache as a dictionary and not send data that can be retrieved from it.

  For example, in an application such as a WEB-based ASP, most of the data has the same contents but only a part is different. For example, there are many forms of data that have the same information written in many fields but differ only in part. Further, for example, there are Web pages that differ only in date or time, and those that differ only in the total access count counter value. In such a case, it is particularly effective.

  Further, differential compression using such a fingerprint also provides an advantage that it is not necessary to predetermine the relationship between data to be transferred and reference data. In other words, in the case of the conventional differential transfer method, it is necessary to decide in advance what the difference is to be taken in both sides. Therefore, if the differential transfer is actually used in the WEB system, the data of this URL is A means for registering a rule such as taking a difference based on data on both sides is necessary, and it has been impossible to function effectively for arbitrary data. On the other hand, this differential compression method takes the difference in the fingerprint cache data as reference data, so that the effect of compressing the data by the difference can be obtained even if the base of the difference is not determined in advance. Obtainable.

  For explanation, when transferring data between the server-side proxy 230 and the client-side proxy 240, the amount of transfer information is compressed by replacing the message body data with the fingerprint of the reference data using a fingerprint cache. This is called differential compression.

  Here, a case will be described as an example where all the messages to be applied to FP compression are to be applied to differential compression. Of course, in the same manner as described above, among messages to which FP compression is applied, a message that satisfies a predetermined condition may be excluded from the application of differential compression (in this case, the difference compression may be performed). The applied condition is obtained by adding another condition to the condition to which FP compression is applied). For example, the upper limit value U2 of the data size not subjected to differential compression is set larger than the upper limit value U1 of the data size not subjected to FP compression (the lower limit L2 of the data size to be differentially compressed is set lower than the lower limit value L1 of the data size to be FP compressed). It is determined by the data size whether it is an application target of FP compression, or whether it is an application target of differential compression, but data other than HTML or XML is an application target of the application target of FP compression. There are various methods, such as a method of performing external compression (differential compression is performed only on HTML or XML data).

  In this embodiment, as a result, the server-side proxy 230 and the client are compressed as either a message whose data is FP compressed, a message whose data is differentially compressed, or a message whose data is not compressed. It is transferred to and from the side proxy 240.

  Here, a differential compression method will be described.

There are various methods of differential compression using a fingerprint cache such as the following.
One of the data registered in the fingerprint cache is used as reference data. Between the proxies, a fingerprint value corresponding to the reference data and information indicating a difference between the transfer data and the reference data are transferred.
In the above method, the data registered in the fingerprint cache is used for all or part of the difference from the reference data. Alternatively, all or part of the transfer data is expressed by combining data (entire or part) registered in the fingerprint cache. For example, any number of data registered in the fingerprint cache is used as reference data. Between the proxies, the fingerprint value corresponding to the reference data, the information indicating the portion of the reference data used for restoring the transfer data, and the information indicating the method for restoring the transfer data based on that portion are transferred. To do.

  Below, an example of the expression method of differential compression data is shown.

  FIG. 6 shows three types of instructions for expressing data to be transferred. The differentially compressed data transferred instead of the data is composed of a sequence of these instructions.

  (A) is an instruction for defining the reference data with a number when referring to the data in the fingerprint cache. The first byte 8n (n = 0 in the example of FIG. 6) is an instruction identifier. Among the instruction identifiers, n indicates that data designated by the fingerprint is handled as nth reference data. 16 bytes starting from the second byte indicate a fingerprint value for the reference data. In this example, 80 to 8F can handle reference data from 0th reference data to 15th maximum. Of course, the maximum number of reference data that can be handled can be more or less depending on the implementation.

  (B) represents an instruction to copy partial data from the reference data defined in (a). 9n in the first byte (n = 0 in the example of FIG. 6) is an instruction identifier. Among the instruction identifiers, n indicates that the nth reference data defined by the instruction (a) is used. The 4 bytes from the 2nd byte indicate the offset position in the nth reference data, and the 4 bytes from the 6th byte indicate the data length. These indicate that data of a specified length from the specified offset position in the nth reference data should be copied (as a constituent part of the transfer data) in accordance with the position (order) of this instruction sequence.

  (C) is an instruction for directly specifying data. A0 in the first byte is an instruction identifier. Four bytes from the second byte indicate the length of the data. The number of bytes specified by the length follows the 6th byte. Then, they indicate that the data after the 6th byte is copied (as a constituent part of the transfer data) in accordance with the position (order) of this instruction sequence.

  The differentially compressed data composed of such a sequence of instructions can be decompressed by simply copying and connecting the data in the order in which they are instructed while referring to the fingerprint cache.

  Next, an example of differential compression according to the above method is shown.

  Assume that data as shown in FIG. 7 is stored in the fingerprint cache as fingerprints 5E83... B6.

  At this time, if data as shown in FIG. 8 is given, differential compression can be performed as shown in FIG. 9 using the data in FIG. 7 as reference data.

  That is, the data in FIG. 8 is merely changed from “TOYO” in FIG. 7 to “OSAKA” as compared with the data in FIG. Therefore, as shown in FIG. 9, first, it is instructed to define the data of fingerprint “5E83... B6” as the 0th reference data at the 0th byte, and from the 0th byte of the 0th reference data to the 17th byte. Instruct to copy bytes, then instruct to copy 5 characters of “OSAKA” at 26th byte, and finally copy 51 bytes from 65th byte of 0th reference data at 36th byte Is instructing.

  If decompression is performed according to this instruction, the data in FIG. 8 can be reproduced.

  In this example, only one reference data is used, but a plurality of reference data can be used.

  Next, another example of differential compression according to the above method will be shown.

  Assume that data as shown in FIG. 10 is in the fingerprint cache as fingerprints 82F3... 38 and data as shown in FIG. 11 is in the fingerprint cache as fingerprints A20D. At this time, if data as shown in FIG. 12 is given, differential compression can be performed as shown in FIG. 13 using the data in FIG. 10 and the data in FIG. 11 as reference data.

  In FIG. 13, first, it is instructed to define the data of the fingerprint “82F3... 38” as 0th reference data at the 0th byte, and 53 bytes from the 0th byte of the 0th reference data are copied at the 17th byte. And instructing to define the fingerprint “A20D... CB” data as the first reference data at the 26th byte, and copying the 55th byte from the 96th byte of the first reference data at the 43rd byte. Is instructing.

  If decompression is performed according to this instruction, the data in FIG. 12 can be reproduced.

  In the above-described method, the method of specifying the portion to be used of the reference data and directly specifying the data to be used (method 1) is used. Instead, the portion of the reference data that is not used (directly). A method (method 2) in which an instruction of a part to be replaced with instruction data and direct designation of data to be inserted into the unused part is also possible.

  It is also possible to use method 1 and method 2 in combination.

  Next, an inter-proxy message format (for a message to which FP compression is applied) when data is transferred between the server-side proxy 230 and the client-side proxy 240 will be described with reference to FIGS. .

  When data is transferred between the server-side proxy 230 and the client-side proxy 240, a message to which FP compression is applied includes a message in which data is FP compressed and replaced with a fingerprint (message at the time of FP compression), A message that is not FP-compressed but has differential-compressed data (message at the time of differential compression), and a message that has data that has not been FP-compressed or differential-compressed (message at the time of non-compression) There is. In the case of a configuration in which not all messages are subject to FP compression, there are messages that are not subject to FP compression in addition to these three messages.

  In the proxy on the transmission side of both proxies, the data is deleted and the fingerprint is added in the message at the time of FP compression, the data is deleted in the message at the time of differential compression, and the data such as the fingerprint of the reference data is restored. Information is added. Data is not deleted for uncompressed messages and messages not subject to compression.

  Of the two proxies, the receiving proxy needs to be able to identify the above three or four types of messages. When a message is received during FP compression, the fingerprint is returned to data, and when a message is received during differential compression, the data is restored. When a message is received at the time of differential compression or non-compression, the fingerprint cache is registered.

  FIG. 14 shows an example of the message format. (A) is a message at the time of non-compression, (b) is a message at the time of differential compression, and (c) is a message at the time of FP compression.

  In (a), data is placed in the message body, in (b) information for restoring the data is placed in the message body instead of data, and in (c), a finger is substituted in the message body instead of data. A print (FP) is placed.

  Also, in this example, identification information for identifying the type of message is described (in the compression proxy) in the message header, and whether or not FP compression is performed based on this identification information (in the decompression proxy). Identify (for example, 01 means no compression, 10 means differential compression, 11 means FP compression). The identification information may be special information used between proxies, or may be information that uses or uses a field originally present in a normal HTTP message header.

  Note that, in a configuration in which a message that is not subject to FP compression may exist, a message of a message that is not subject to FP compression, as shown in FIG. 14D, in the proxy on the compression side (transmission side). -The identification information (for example, 00) may be included in the header.

  Further, in a configuration in which a message that is not subject to FP compression may exist, the message on the decompression side (reception side) proxy is a message that is not subject to FP compression due to some information included in the message header. When it is possible to determine whether or not the message body is null and the message is determined not to be subject to FP compression, the FP compression is not applicable. It is also possible not to include identification information in the message header of the message.

  Here, FIG. 39 shows a specific example of the message in the format of FIG. 14A, FIG. 40 shows a specific example of the message in the format of FIG. 14B, and FIG. 41 shows the format of the message in FIG. A specific example of the message is shown, and FIG. 42 shows a specific example of the message in the format of FIG. “Fingerprint-Mode:...” In the header of each figure corresponds to the identification information, and “6E39... 0128” in the body in FIG. 41 corresponds to the fingerprint.

  In the example of FIGS. 14A and 14B, the fingerprint for the data is not included in the message at the time of non-compression or differential compression. However, the fingerprint may be included in the message header. Good (or a fingerprint for the data may be included in the message body). FIGS. 15A to 15C show an example in which a fingerprint is included in the message header at the time of non-compression or differential compression, and a fingerprint is included in the message body at the time of FP compression. In this way, when the fingerprint cache is registered for the data on the decompression side, it is possible to save time and effort for obtaining the fingerprint from the data again by using the fingerprint.

  FIG. 43 shows a specific example of the message in the format of FIG. 15A, and FIG. 44 shows a specific example of the message in the format of FIG. A specific example of the message in the format of FIG. 15C is the same as that in FIG. “Fingerprint:...” In the headers of FIGS. 43 and 44 corresponds to a fingerprint.

  In any of the above cases, as shown in FIG. 16, in the message at the time of FP compression, a fingerprint (FP) may be included in the message header, and the message body may be null.

  FIG. 45 shows a specific example of the message in the format of FIG.

  In addition to the above, various message formats are possible.

  For example, in FIG. 17, the uncompressed flag is described in the header of the message at the time of (a) uncompressed and the fingerprint is not described, and the differential compression flag is described in the header of the message at the time of differential compression of (b). Also, the fingerprint is not described, the fingerprint is described in the header of the message at the time of FP compression in (c), and the body is null.

  In this case, it is possible to identify that the message is a message at the time of FP compression by detecting that the message body is null or the fingerprint is described in the header of the message. it can. Further, a message at the time of non-compression and a message at the time of differential compression can be identified by detecting that a non-compression flag or a differential compression flag is described in the header.

  46 shows a specific example of the message in the format of FIG. 17A, FIG. 47 shows a specific example of the message in the format of FIG. 17B, and FIG. 48 shows the message of the format in FIG. A specific example is shown. “Non-Compression:...” In the header of FIG. 46 corresponds to an uncompressed flag, and “Differential-Compression:...” In the header of FIG.

  In the case of a configuration in which a message that is not subject to FP compression may exist, in the proxy on the compression side (transmission side), as shown in (a) and (b) of FIG. If (b) is not null (if the data is null), a non-target flag may be included in the message header of a message that is not subject to FP compression.

  Further, in a configuration in which a message that is not subject to FP compression may exist, the message on the decompression side (reception side) proxy is a message that is not subject to FP compression due to some information included in the message header. 18 (c) and 18 (d), (c) indicates that the data is not empty (null), and (d) indicates that the data is empty (null). ) It is also possible not to include a non-target flag in the message header of a message that is not subject to FP compression.

  FIG. 49 shows a specific example of a message in the format of FIG. 18A, FIG. 50 shows a specific example of a message in the format of FIG. 18B, and FIG. 51 shows a specific example of a message in the format of FIG. An example is shown, and FIG. 52 shows a specific example of the message in the format of FIG. “No-FP-Compression:...” In the headers of FIGS. 49 and 50 corresponds to the non-target flag.

  In the following, the present embodiment will be described in detail with a focus on the case where the reply data is transferred to the client side proxy 240 from the server side proxy 230 and the reply data is FP compressed / decompressed.

  FIG. 19 shows a configuration example of the server-side proxy 230 of this embodiment, and FIG. 20 shows a configuration example of the client-side proxy 240 of this embodiment. 19 and 20 mainly show the configuration when data is transferred from the server-side proxy 230 to the client-side proxy 240.

  As shown in FIG. 19, the server-side proxy 230 includes a receiving unit 231 that performs processing for receiving a transfer message from the intra-server center LAN 212 or the wide area network 214, FP compression on the data included in the transfer message, A processing unit 232 for performing differential compression, a transmission unit 233 for performing processing for transmitting a transfer message to the intra-server center LAN 212 or the wide area network 214, and storing fingerprints in association with the original data A fingerprint cache (FP cache) 234 is provided. In addition, the processing unit 232 performs search and registration for the fingerprint (FP) compression determination unit 2321 and the fingerprint cache 234 for determining whether or not the data included in the transfer message is to be compressed. Fingerprint cache (FP cache) management unit 2322, fingerprint (FP) compression processing unit 2323 for performing processing such as replacing the data included in the transfer message with the corresponding fingerprint, and the difference between the data included in the transfer message A differential compression processing unit 2324 for performing processing such as replacement with compressed data is included.

  As shown in FIG. 20, the client-side proxy 240 includes a receiving unit 241 that performs processing for receiving a transfer message from the user office LAN 216 or the wide area network 214, and performs FP decompression on the data included in the transfer message. A processing unit 242 for performing processing, a transmission unit 243 for performing processing for transmitting a transfer message to the LAN 216 in the user office or the wide area network 214, and a finger for associating and storing the fingerprint and the data on which the fingerprint is generated A print cache (FP cache) 244 is provided. Further, the processing unit 242 determines whether or not the data included in the transfer message should be compressed, and includes a fingerprint (FP) compression determination unit 2421 for determining whether there is FP compression and differential compression for the transfer message. Fingerprint cache (FP cache) management unit 2422 for performing search and registration for the cache 234, fingerprint for performing processing such as decompressing the original data from the fingerprint included in the FP compressed transfer message The (FP) decompression processing unit 2423 includes a differential decompression processing unit 2424 for performing processing such as decompressing the original data from the differentially compressed data included in the differentially compressed transfer message.

  Note that the compression side FP compression determination unit 2321 and the decompression side FP compression determination unit 2421 check whether the message satisfies a predetermined condition as described above, thereby converting the data included in the message into the FP. It is determined whether or not to apply compression (when all messages are to be applied to FP compression, the FP compression determination unit 2321 on the compression side and the corresponding part of the procedure example shown below are unnecessary, and decompression is performed. The corresponding determination part of the FP compression determination unit 2421 on the side and the corresponding part of the procedure example shown later are unnecessary). Further, the decompression-side FP compression determination unit 2421 determines whether or not the data of the FP compression target message is FP compressed. In the following, description will be focused on the case of transferring a message to which FP compression is applied (when it is determined that FP compression is to be applied, or when all messages are to be applied to FP compression).

  FIG. 21 and FIG. 22 show an example of the processing procedure of the server-side proxy 230 when the reply message is transferred from the server-side proxy 30 to the client-side proxy 240. 21 and 22 describe the processing when one reply message is received, but the processing illustrated in FIGS. 21 and 22 is actually performed for all reply messages received by the server-side proxy 230. I do.

  The server-side proxy 230 receives a reply message from the server 220 by the receiving unit 231 (step S201).

  The FP compression determination unit 2321 checks and determines whether the reply data of the reply message is for FP compression (step S202). If it is determined that the reply data is not subject to FP compression (step S202), the received reply message is transferred from the transmission unit 33 to the client side proxy 240 (step S212).

  If it is determined in step S202 that the reply data of the reply message is for FP compression, the FP cache management unit 322 calculates a fingerprint value of the reply data (step S203). The fingerprint cache 234 is searched using the fingerprint value as a key (step S204).

  If a set of the fingerprint value and the data corresponding to the fingerprint value is registered in the fingerprint cache 234 (step S205), the FP compression processing unit 2323 sends the received reply message to the fingerprint cache. The print value is used for the FP compression format (for example, FIG. 16) and transmitted from the transmission unit 233 to the client-side proxy 240 (step S206).

  On the other hand, as a result of the search in step S204, if the set of the fingerprint value and the corresponding data is not registered in the fingerprint cache 234 (step S205), the differential compression processing unit 2324 Differential compression is performed (step S207), and it is determined whether or not the differential compression is successful (step S208).

  Whether or not the differential compression has succeeded is determined if, for example, the data amount r0 of the original data targeted for differential compression is compared with the data amount r1 of the differential compression data, and if r0−r1> d is satisfied, Judge that Here, the constant d is a predetermined integer of 0 or more.

If it is determined in step S208 that the differential compression is successful, the following two operations are performed.
(1-1) In the differential compression processing unit 2324, the received reply message is converted into a format at the time of differential compression (for example, using the fingerprint value if necessary) (for example, FIG. 15B). The transmission unit 233 transmits to the client side proxy 240 (step S209).
(1-2) The FP cache management unit 2322 associates the fingerprint value with the reply message (using the fingerprint value as a key) and registers the fingerprint value in the fingerprint cache 234 (step S211). ).

  Note that either (1-1) and (1-2) may be performed first or in parallel.

On the other hand, if it is determined in step S208 that the differential compression has failed, the following two operations are performed.
(2-1) The differential compression processing unit 2324 converts the received reply message into a non-compressed format (for example, FIG. 15A) and transmits it from the transmission unit 233 to the client side proxy 240 (step) S210).
(2-2) The FP cache management unit 2322 associates the fingerprint value with the reply message (using the fingerprint value as a key) and registers it in the fingerprint cache 234 (step S211). ).

  In (2-1) above, the received reply message may be in a non-compressed format in the FP compression processing unit 2323 instead of the differential compression processing unit 2324.

  Moreover, either (2-1) and (2-2) may be performed first or in parallel.

  Next, FIG. 23 and FIG. 24 show an example of the processing procedure of the client side proxy 240 when the reply message is transferred from the server side proxy 230 to the client side proxy 240. 23 and 24 describe the processing when one request message is received. Actually, the processing illustrated in FIGS. 23 and 24 is performed for all the request messages received by the client-side proxy 240. I do.

  The client side proxy 240 receives a reply message from the server side proxy 230 by the receiving unit 241 (step S211).

  The FP compression determination unit 2421 determines whether or not the reply data of the reply message is for FP compression (step S212). If it is determined that the reply data is not subject to FP compression (step S212), the received reply message is transferred from the transmission unit 43 to the client 250 (step S224).

  If it is determined in step S212 that the reply data of the reply message is for FP compression, the FP compression determination unit 2421 further checks whether or not the reply data is FP compressed (step S212). S213).

  If it is determined in step S213 that the reply data of the reply message is FP-compressed (for example, in the case of FIG. 16 or the like), the FP cache management unit 2422 obtains the fingerprint value of the reply data. (Step S214), the fingerprint cache 244 is searched using the fingerprint value as a key (Step S215).

  When the FP decompression processing unit 2423 adds data corresponding to the fingerprint value retrieved from the fingerprint cache 234 to the received reply message and uses special information between proxies. After deleting the information, transmits the information from the transmission unit 243 to the client 250 (step S216).

  On the other hand, if it is determined in step S213 that the reply data of the reply message is not FP-compressed (for example, in the case of FIGS. 15A and 15B), the FP compression determination unit 2421 further It is determined whether or not the reply data is differentially compressed (step S217).

If it is determined in step S217 that differential compression has been performed (for example, in the case of FIG. 15B), the following two operations are performed.
(1-1) The differential decompression processing unit 2424 decompresses the differential compressed data (after retrieving and acquiring the reference data by the FP cache management unit 2422) to restore the original reply data (step S218), When the restored reply data is added to the reply message, or when special information is used between proxies, the information is deleted from the received reply message, and the reply message is transmitted from the transmission unit 243 to the client 250 (step S219). ).
(1-2) The FP cache management unit 2422 obtains the fingerprint value of the reply data (step S220), associates the fingerprint value with the reply message (uses the fingerprint value as a key) And register it in the fingerprint cache 234 (step S223).

On the other hand, if it is determined in step S217 that differential compression has not been performed (for example, in the case of FIG. 15A), the following two operations are performed.
(2-1) In the case where the difference decompression processing unit 2424 uses special information between proxies, the information is deleted from the received reply message and then transmitted from the transmission unit 243 to the client 250 (step S222). ).
(2-2) The FP cache management unit 2422 obtains the fingerprint value of the reply data (step S221), associates the fingerprint value with the reply message (uses the fingerprint value as a key) And register it in the fingerprint cache 234 (step S223).

  In (2-1) above, the processing may be performed not by the differential decompression processing unit 2424 but by the FP decompression processing unit 2423.

  In addition, (1-1) and (1-2) may be performed first or in parallel. The same applies to the above (2-1) and (2-2).

  By the way, in step S214 / step S220 / step S221, when the fingerprint is described in the message, the method for obtaining the fingerprint from the message, and when the fingerprint is not described in the message, the reply data is also stored. In addition, there is a method of calculating a fingerprint value by a hash function or the like. Even when the fingerprint is described in the message, a method of calculating the fingerprint value based on the reply data is also possible. Further, step S214 / step S220 / step S221 may be performed at an arbitrary timing before the fingerprint is used. However, in the latter method, the calculation in step S220 needs to be performed after step S218.

  The determinations in steps S212, S213, and S217 may be performed simultaneously.

  Next, a procedure for performing differential compression will be described.

  FIG. 25 shows an example of the differential compression procedure. This is a procedure example in the case of using the three types of designation described above.

  Here, in order to perform differential compression, it is assumed that a history table in which recently accessed data is sequentially arranged among the data stored in the fingerprint cache is used. This history table does not necessarily need to record the fingerprints of all data stored in the fingerprint cache. For example, a predetermined number may be recorded (in this case, the number is determined in advance assuming a number effective for use as reference data for differential compression, for example). Of course, one or a plurality of criteria other than the order of recent access may be used as the criteria for recording in the history table, and one or more other criteria may be used in addition to the criteria of the order of recent access. May be.

  There is also a method in which the history table is configured integrally with the fingerprint cache.

  (Step S231) First, the working copy buffer and instruction buffer are emptied.

  Based on the contents copied to the copy buffer, the instructions in FIGS. 6A to 6C are created and written to the instruction buffer. Finally, the sequence of instructions written in the instruction buffer becomes differentially compressed data.

  (Step S232) Data to be subjected to differential compression is handled as a character string, and a pointer pointing to the character string is prepared. First, the pointer is set to point to the first character in the character string.

  In the following, loop processing is executed until it is determined in step S241 that the pointer has reached the last character in the character string.

  (Step S233) The data corresponding to the fingerprints recorded in the history table are taken out in order from the newest one, and the data matches the predetermined length from the location indicated by the pointer in the data to be differentially compressed. Retrieve data as reference data.

  There are various reference data and determination methods. For example, a method of examining data corresponding to fingerprints recorded in the history table in the latest order, and first extracting data that matches a predetermined length or more as reference data, fingerprints recorded in the history table There is a method in which all of the data corresponding to the above are examined, and the data having the longest matching length (provided that the matching is longer than a predetermined length) is taken out as reference data.

  (Step S234) If the reference data is found, the process proceeds to Step S237. If the reference data is not found, the process proceeds to step S235.

  (Step S237) When the reference data is found in Step S234, if the copy buffer is not empty, a copy instruction by direct designation in FIG. 6C corresponding to the character string in the copy buffer is created. Write this to the instruction buffer. The copy buffer is emptied. If the copy buffer is empty, nothing is done.

  (Step S238) If the reference data definition in FIG. 6A corresponding to the reference data found in step S233 has not yet been written to the instruction buffer, the reference data definition instruction is written to the instruction buffer.

  (Step S239) The copy instruction of the matched character string from the reference data is written in the instruction buffer as the copy instruction of FIG.

  (Step S240) The pointer is advanced by the length of the character string that matches the reference data.

  (Step S235) On the other hand, when the reference data is found in Step S234, the character pointed to by the pointer is placed in the copy buffer.

  (Step S236) The pointer is advanced by one character.

  (Step S241) If the pointer has not come to the end of the data to be subjected to differential compression (if there is an unprocessed data portion), the process returns to Step S233. If the pointer has come to the end of the data to be subjected to differential compression (if no unprocessed data portion remains), the processing loop is exited and the process proceeds to step S242.

  (Step S242) If the copy buffer is not empty, a copy instruction by direct designation in FIG. 6C corresponding to the character string in the copy buffer is created and written to the instruction buffer. The copy buffer is emptied. If the copy buffer is empty, nothing is done.

  The contents of the instruction buffer at this time become differentially compressed data.

  In addition, as described above, after the differential compression is actually performed in this way, the data size as a result of the differential compression is smaller than the data size before the execution (or a constant standard (constant Confirm that it is smaller than the compression amount). If the data size is not reduced by differential compression (or if it does not decrease beyond a certain standard (a certain amount of compression)), it is better not to perform differential compression, so the data is transferred as it is.

By the way, in the differential compression process described above, the process of selecting the latest data having a character string that matches the predetermined length or more in step S233 is considered to be the process that takes the longest time. To speed up this process, a hash table can be used. Extract all the character strings of a predetermined length from the data to be entered in the history table, calculate the hash value (for example, the sum of all the character codes), and register it in the hash table. Keep it. This hash table is overwritten with the latest data if there is data having the same hash value.
Using this hash table, the hash value of a character string of a predetermined length is obtained from the current pointer position of the data to be differentially compressed, and the data obtained by subtracting the hash table using the hash value is the step It becomes the first candidate of data to be selected in S233. Here, since the same hash value may be generated even in different character strings, whether or not they are really the same is confirmed by actually comparing the character strings. Search for candidates.

Another method for speeding up the processing in step S233 is a method of performing comparison processing in units of rows. In the procedure of FIG. 25, comparison processing is performed in units of characters. For all data in the history table, a hash value column for each row in the data is calculated. First, a column of hash values of each row is calculated from data to be differentially compressed. The subsequent steps are the same as those in FIG. 25, but the comparison is performed not in units of characters but in units of row hash values. Since this method uses a line as a unit, the number of comparisons can be reduced as compared with a character unit. However, in order to compare by hash value, there may be the same hash value in different rows, so after finally judging that the hash values are the same, whether or not they are really the same by actually comparing the rows It is desirable to judge.
Of course, the above-described hash technique can be combined for such a configuration in which the comparison is performed in units of rows. In this case, a plurality of consecutive rows may be combined and registered in the hash table in units of the minimum number of rows that is the same as or longer than a predetermined length.

  Next, FIG. 26 shows another example of the differential compression procedure. This uses one of the data registered in the fingerprint cache as reference data, and between the proxies, the fingerprint value corresponding to the reference data, and information indicating the difference between the transfer data and the reference data It is an example of a procedure when transferring.

  Again, the history table as described above is used.

  First, of the data corresponding to the fingerprints recorded in the history table, one satisfying a predetermined standard is selected as reference data (step S245).

  The predetermined standard is, for example, that the data amount of a portion that does not match the reference data among the data to be subjected to differential compression is equal to or less than a predetermined data amount, and the reference When the data is divided into a plurality of chunks by the unmatched portion, if the number of the divided chunks is equal to or less than a predetermined number, this can be selected as reference data.

  As a method for determining the reference data, as described above, for example, the data corresponding to the fingerprints recorded in the history table are checked in the latest order, and the data that matches the predetermined length or more at first As a reference data, to examine all of the data corresponding to the fingerprint recorded in the history table, to extract the data that did not match and the data with the least number of divisions as reference data, etc. There are various methods.

  If reference data is found (step S246), a reference data definition instruction (for example, FIG. 6A) is written to the instruction buffer (step S247).

  An instruction indicating a part of the reference data that has not been matched (a part to be replaced with the directly specified data) (for example, an instruction having the same format as that of FIG. Writing to the buffer (step S248).

  A direct designation instruction (for example, (c) in FIG. 6) indicating data to be inserted into the unmatched portion of the reference data is written to the instruction buffer (step S249).

  If there are a plurality of replacement parts, step S248 and step S249 are executed accordingly.

  The contents of the instruction buffer at this time become differentially compressed data.

  On the other hand, if reference data is found (step S246), differential compression is not performed.

  In the description of FIG. 25 and FIG. 26 described above, the history table is provided separately from the fingerprint cache. However, there is a method in which the history table is integrated with the fingerprint cache.

  In the above description, the history table is used. However, there is a method that does not use the history table. For example, the fingerprint cache is checked in a predetermined order (for example, in order of entry or at random) by a predetermined upper limit number, and the best one of them is used. There are various methods such as a method in which reference data is determined in a predetermined order (for example, in order of entry or randomly), and the reference data satisfying a predetermined condition is obtained for the first time.

  In addition to the fingerprint, the history table or fingerprint cache also stores the URL of the reply message that included the reply data that was the original when the fingerprint was registered, and stores the reference data. When searching, first, it is checked whether or not data having the same URL as the reply message including the reply data to be subjected to differential compression is registered in the history table or the fingerprint cache. Data having the same URL as the URL may be prioritized over other data to check whether it can be used as reference data.

  Of course, in addition to FIG. 25 and FIG. 26, various differential compression procedures are possible.

  In the case where the fingerprint cache is not used when the request message is transferred from the client side proxy 240 to the server side proxy 230, the server side proxy 230, as illustrated in FIG. The procedure of receiving a request message from the proxy 240 (step S225) and transmitting it to the server 220 (step S226) may be used. Similarly, as illustrated in FIG. 28, the client-side proxy 240 may receive a request message from the client 250 (step S227) and transmit it to the server-side proxy 230 (step S228).

  Hereinafter, with reference to FIG. 29 (during registration, ie, uncompressed), FIG. 30 (during FP compression), and FIG. 31 (during registration, ie, differential compression), more specific data transfer using the fingerprint cache will be described. Explained.

  First, referring to FIG. 29, data that has not been registered in the fingerprint cache and that has not been successfully compressed is transferred from the server-side proxy 230 to the client-side proxy 240. The operation when registering a print cache will be described.

  (1) It is assumed that the browser or the like on the client 250 issues a POST method request message to the server 220 with a URL of “/A.cgi”, for example. First, a browser or the like is set so that a request message to the server 220 is sent to the client-side proxy 240.

  (2) The client-side proxy 240 that has received the request message from the client 250 transfers the request message to the server-side proxy 230.

  (3) The server-side proxy 230 that has received the request message transfers the request message to the server 250.

  (4) After processing the request message, the server 220 sends the reply message back to the server-side proxy 230.

  (5) Upon receiving the reply message, the server-side proxy 230 first calculates the fingerprint of the reply data included in the received reply message, and determines whether the data having the fingerprint name is in the fingerprint cache 234. Investigate. Here, for the first time not entered, the data that was registered in the fingerprint cache is deleted or invalidated in the case of the configuration that may be deleted or invalidated afterwards. Therefore, the data is put (registered) in the fingerprint cache 234 with the fingerprint as a name.

  If the data to be compressed cannot be FP-compressed, differential compression processing is performed, and if the reply data can be differentially compressed to reduce the amount of data, differential compression is performed. The amount of data could not be reduced by differential compression.

  (6) The server-side proxy 230 transfers a reply message carrying data to the client-side proxy 240. As described above, when the fingerprint value calculated from the reply data is sent in the reply header or the like, the trouble of calculating the fingerprint again by the client side proxy 240 can be saved.

  (7) Since the client-side proxy 240 that has received the reply message is the first data, it registers the reply data in the fingerprint cache 244. 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 this is entered as a name.

  (8) The client-side proxy 240 deletes (in the case of a configuration in which information used only between the server-side proxy 230 and the client-side proxy 240 such as a fingerprint value exists in the reply header or the like) After that, a reply message is sent back to the client 250 (such as a browser operating on the client 250).

  The server-side proxy 230 may perform the above-described fingerprint cache registration (5) after the operation (6). In the client-side proxy 240, the fingerprint cache registration of (7) may be performed after the operation of (8).

  Next, with reference to FIG. 30, an operation in the case where the data registered in the cache by performing the operation of FIG. 29 is transferred from the server-side proxy 230 to the client-side proxy 240 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 250, the server-side proxy 240 first calculates the fingerprint of the reply data included in the received reply message, and the data having the fingerprint name enters the fingerprint cache 234. Find out if it is. Since the fingerprint cache is registered here, the reply body data is replaced with the fingerprint (for example, by inserting the fingerprint value into the reply header or the like and emptying the reply body as described above).

  (6) The server-side proxy 230 transfers a reply message in which the reply body is replaced with a fingerprint to the client-side proxy 240.

  (7) Upon receiving the reply message, the client-side proxy 240 detects that the reply data has been replaced with the fingerprint, and uses the specified fingerprint (for example, in the reply header as described above) The corresponding data is fetched from the print cache 244 and placed in the reply body. In addition, in the case where the information used only between the server-side proxy 230 and the client-side proxy 240 is present in the reply header or the like, such as a fingerprint value, this is deleted.

  (8) Then, the client-side proxy 230 returns a reply message to the client (such as a browser operating on the client).

  By the way, since the fingerprint caches of the server side proxy 230 and the client side proxy 240 have an upper limit in capacity, garbage collection is performed according to a predetermined algorithm, for example, erasing old data or data that is unlikely to be used. Is preferred.

  However, in this case, even if the fingerprint cache 234 of the server-side proxy 230 is held, data that has been deleted in the fingerprint cache 244 of the client-side proxy 240 can be generated. In the above (7), the client-side proxy 240 tried to extract data to replace the reply data from the fingerprint cache 244 based on the fingerprint, but the fingerprint and data corresponding to the fingerprint cache 244 May not exist. In such a case, for example, the client-side proxy 240 requests the server-side proxy 230 to send data of the designated fingerprint, and the requested server-side proxy 230 sends the designated fingerprint. It is sufficient to provide a mechanism for fetching the data from the fingerprint cache 234 and sending it back.

  On the other hand, when there is data already deleted in the fingerprint cache 234 of the server side proxy 230 but still in the fingerprint cache 244 of the client side proxy 240, FIG. When the fingerprint / reply data is registered in the fingerprint cache 244 in the client-side proxy 240 in (7) in the operation described with reference to the fingerprint / reply data registered at that time. May be overwritten.

In the operation (5) described with reference to FIG. 30, the server-side proxy 230 obtains the fingerprint of the reply data, and if the fingerprint is in the fingerprint cache 234, the same data as the corresponding ply data. Are processed in the fingerprint cache 234 as a pair with the fingerprint. In practice, this method is sufficient if the same fingerprint is not generated from different data, but an error that occurs when the fingerprints of different data accidentally become the same value with a very small probability. There is also a way to get rid of. In this case, when the fingerprint obtained from the reply data is stored in the fingerprint cache 234, the data paired with the fingerprint and stored in the fingerprint cache 234 and the ply data are combined. What is necessary is just to judge whether it is the same by comparing. At this time, if it is determined that data having the same fingerprint but different contents is registered, a method exemplified below can be considered.
The fingerprint is not used anymore (the data giving the fingerprint will not be cached thereafter).
Prioritize the previously registered fingerprint / data (other data giving the same fingerprint value as the fingerprint being registered will not be cached during the registration).
Prioritize the fingerprint / data that is currently registered (the fingerprint / data being registered will be updated one after another by other data giving the same value fingerprint).

  The operation of this embodiment for performing differential transfer will be described with reference to FIG.

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

  (5) Upon receiving the reply message, the server-side proxy 230 first calculates the fingerprint of the reply data included in the received reply message, and determines whether the data having the fingerprint name is in the fingerprint cache 234. Investigate. Here, since it is not entered and is the first data, the data is entered (registered) in the fingerprint cache 234 with the fingerprint as a name.

  (6) If the data to be compressed cannot be FP compressed, differential compression processing is performed, and if the reply data can be differentially compressed to reduce the data amount, differential compression is performed. Here, it is assumed that when data having a fingerprint of “71F0... 73E6” is used as reference data, the reply data is differentially compressed to reduce the data amount. Reply data is replaced with differential compression data, and information indicating that differential compression has been performed is put in a reply header or the like.

  (7) The server side proxy 230 transfers the reply message to the client side proxy.

  (8) The client-side proxy 240 sees the reply header and the like, knows that the reply data is differentially compressed, and decompresses the compression. At this time, first, the fingerprint “71F0... 73E6” of the reference data designated in the compressed data is extracted, and then the data corresponding to the fingerprint is extracted from the fingerprint cache and used. Put the decompressed data in the reply data and rewrite the necessary headers such as the content size of the reply header.

  (9) Since the client side proxy 240 receiving the reply message is the first data, it registers the decompressed reply data in the fingerprint cache 244. In addition, in the case where the information used only between the server-side proxy 230 and the client-side proxy 240 is present in the reply header or the like, such as a fingerprint value, this is deleted. 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 this is entered as a name.

  (10) The client-side proxy 240 sends a reply message back to the client 250 (such as a browser operating on the client 250).

  In (5) above, all unregistered data to be compressed is registered in the fingerprint cache, and all the data used as reference data in (6) above is the fingerprint cache. However, when the only data is used for the reference data and the data subject to differential compression is almost the same as the reference data used for the differential compression ( For example, if the amount of data that does not match is below the standard), (i) unregistered data to be compressed is not registered in the fingerprint cache, and the reference data maintains the fingerprint cache registration Or (ii) Register unregistered data to be compressed in the fingerprint cache and reference data as fingerprint To remove from the cache, it is also possible to methods such as. In addition, when the only data is used for the reference data, the data subject to differential compression and the reference data used for the differential compression have almost the same contents and the same URL. In this case, it is possible to register the unregistered data to be compressed in the fingerprint cache and delete the reference data from the fingerprint cache, assuming that the data has been updated. There are various other variations.

  By the way, in the example described so far, when the reply data is transferred from the server-side proxy 230 to the client-side proxy 240, the fingerprint cache is used, and a set of a certain data and a fingerprint corresponding thereto is used as a fingerprint. The data is registered in the cache when the data is transferred from the server side proxy 230 to the client side proxy 240 for the first time. However, in the usage such as WEB-based ASP, for example, the data is first created in the user office or the like and registered in the server and accessed from the browser or the like in many cases. If the data is registered in the fingerprint cache of the client-side proxy and the server-side proxy at the time when the data is registered in the server, subsequent access can be speeded up. Therefore, if the reply data sent by the server is data originally transferred from the client to the server (however, in this case, request data), the registration request is sent to the original request data as the reply data. May be transferred from the client side proxy 140 to the server side proxy 130 for the first time (in this case, when the data becomes reply data and is transferred from the server side proxy 130 to the client side proxy 140 for the first time). Since the registration to the fingerprint cache has already been completed, even if it is the first transfer of reply data, the amount of transferred data can be reduced by using the fingerprint cache. it can).

  In the example described so far, when the reply data is transferred from the server-side proxy 230 to the client-side proxy 240, if the reply data is the same as the data registered in the fingerprint cache, The network traffic is reduced by transferring a corresponding fingerprint or differentially compressed data instead of the reply data, but the present invention reduces the request from the client side proxy 240 to the server side proxy 230. The present invention can be further applied to the case of transferring data.

  In addition, when applying FP compression to both, it is also possible to apply differential compression only about either one.

  It is also possible to apply FP compression and differential compression only when request data is transferred from the client side proxy 240 to the server side proxy 230.

  When FP compression and differential compression are applied to request data transfer from the client-side proxy 240 to the server-side proxy 230, the roles of the server-side proxy 230 and the client-side proxy 240 for the reply data already described may be reversed. When the FP compression and differential compression are applied to both data transfers, the server-side proxy 230 further includes a fingerprint decompression processing unit and a differential decompression processing unit in the processing unit 232 in addition to the configuration of FIG. In addition to the configuration of FIG. 20, the proxy 240 may further include a fingerprint compression processing unit and a differential compression processing unit in the processing unit 242.

  In any proxy, the fingerprint compression processing unit and the fingerprint decompression processing unit may be combined into a fingerprint (FP) compression / decompression processing unit. Similarly, the differential compression processing unit and the differential decompression processing unit may be combined into a differential compression / decompression processing unit.

  In addition, the server-side proxy 230 and the client-side proxy 240 may be provided with a fingerprint cache for request data transfer independently of the fingerprint cache for reply data transfer, but the same for reply data transfer and quest data transfer The fingerprint cache may be shared. In the case of the configuration using the above-described history table at the time of differential compression, the history table may be provided independently as well, or may be shared.

  FIG. 32 shows a configuration example of the proxy (server side proxy, client side proxy) in this case.

  FIG. 33 and FIG. 34 show an example of a processing procedure of the client side proxy 240 when transferring a request message from the client side proxy 240 to the server side proxy 230. 33 and 34 are the same as in FIG. 21 and FIG. 22, in which the message to be transferred changes from the reply message to the request message, the message transmission source changes from the server to the client, the message transmission destination changes from the client to the server, and the server side proxy 40 And the operation of the client side proxy 40 are interchanged.

  35 and 36 show an example of a processing procedure of the server side proxy 230 when transferring a request message from the client side proxy 240 to the server side proxy 230.

  35 and 36, in FIG. 23 and FIG. 24, the message to be transferred changes from the reply message to the request message, the message transmission source changes from the server to the client, the message transmission destination changes from the client to the server, and the server side proxy 40 And the operation of the client side proxy 40 are interchanged.

  In this way, if the request data is also replaced with fingerprints or differentially compressed data, for example, when uploading the same file to the server many times, it is only necessary to send the fingerprint after the second time. Network traffic can be reduced.

  In the present embodiment, the request message transferred from the client-side process to the server-side proxy and the reply message transferred from the server-side proxy to the client-side process have been shown. If both the device that sends the request message and the device that sends the reply message, or the device that sends both the request message and the reply message are connected, of course, it is transferred from the client side process to the server side proxy. Target request messages and reply messages, and request messages and reply messages transferred from the server side proxy to the client side process. It is also such that the target only request message transmitted from the request message and the server side proxy is transferred to the side proxy to the client process.

  By the way, the description has so far been focused on the one-to-one communication between one server-side proxy and one client-side proxy. Of course, the scope of the present invention is not limited to the server-side proxy and the client-side proxy. The system is not limited to a one-to-one communication system, but a server-side proxy and a client-side proxy communicate one-to-many, and a server-side proxy and a client-side proxy communicate many-to-one. Alternatively, the present invention can be applied to a system in which a server-side proxy and a client-side proxy communicate many-to-many. For example, as shown in FIG. 37, a client-side proxy installed in a plurality of user offices, a personal proxy used by a mobile user, or the like can be implemented so as to share and use the server-side proxy.

  In the past, the entire data included in one message was subject to FP compression (target to be registered in the fingerprint cache). For example, the data included in one message is the data of a predetermined unit. In the case of being configured as a set, a configuration in which only a part of unit data included in one message is subject to FP compression (target to be registered in the fingerprint cache) is also possible.

  The URL specified in the request message issued by the client for the reply data that can be cached by the shared cache mechanism of the proxy in the server side proxy or the client side proxy (or both) of the present embodiment A reply data included in the reply message corresponding to the request message, a fingerprint corresponding to the reply data, and a request header such as the MIME type included in the reply header of the reply message. Information necessary for configuration and information such as a time stamp to be used for determining the validity period are cached in association with each other (may be stored in the fingerprint cache or information excluding reply data (URL) And fu Emissions fingerprinting and may be separately provided a correspondence table that holds other information)), by a combination of this with fingerprint cache, it is possible to perform also an operation of the shared cache of the proxy server. For example, when the cache function is provided in the client-side proxy, when the reply data for the URL specified in the request message transmitted by the client is cached and the data is valid, the client-side proxy Can retrieve data corresponding to the URL from the fingerprint cache, create a reply message, and respond to the client.

Each function described above can be realized as software.
The present embodiment can also be implemented as a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means, or for causing a computer to realize predetermined functions), The present invention can also be implemented as a computer-readable recording medium on which the program is recorded.

Note that the configuration illustrated in the embodiment of the present invention is an example, and is not intended to exclude other configurations, and a part of the illustrated configuration may be replaced with another or one of the illustrated configurations. Other configurations obtained by omitting a part, adding another function or element to the illustrated configuration, or combining them are also possible. Also, another configuration that is logically equivalent to the exemplified configuration, another configuration that includes a portion that is logically equivalent to the exemplified configuration, another configuration that is logically equivalent to the main part of the illustrated configuration, and the like are possible. is there. Further, another configuration that achieves the same or similar purpose as the illustrated configuration, another configuration that achieves the same or similar effect as the illustrated configuration, and the like are possible.
In addition, various variations of various components illustrated in the embodiment of the present invention can be implemented in appropriate combination.

Further, the embodiment of the present invention is an invention of an invention as an individual device, an invention of two or more related devices, an invention of the entire system, an invention of components within an individual device, or a method corresponding thereto. The invention includes inventions according to various viewpoints, stages, concepts, or categories.
Therefore, the present invention can be extracted from the contents disclosed in the embodiments of the present invention without being limited to the exemplified configuration.

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

The figure which shows the structural example of the computer network system which concerns on one Embodiment of this invention. The figure which shows the other structural example of the computer network system which concerns on the embodiment The figure which shows the further another structural example of the computer network system which concerns on the embodiment The figure for demonstrating the fingerprint used in the embodiment The figure for demonstrating the fingerprint cache used in the embodiment The figure for demonstrating the instruction | indication method of the differential compression used in the embodiment The figure for demonstrating the specific example of the differential compression of the embodiment The figure for demonstrating the specific example of the differential compression of the embodiment The figure for demonstrating the specific example of the differential compression of the embodiment The figure for demonstrating the other specific example of the differential compression of the embodiment The figure for demonstrating the other specific example of the differential compression of the embodiment The figure for demonstrating the other specific example of the differential compression of the embodiment The figure for demonstrating the other specific example of the differential compression of the embodiment A diagram showing an example of a message format used in the embodiment A diagram showing another example of a message format used in the embodiment A diagram showing still another example of a message format used in the embodiment A diagram showing still another example of a message format used in the embodiment A diagram showing still another example of a message format used in the embodiment The figure which shows the structural example of the server side proxy which concerns on the same embodiment The figure which shows the structural example of the client side proxy which concerns on the same embodiment The flowchart which shows the example of a procedure of the server side proxy which concerns on the same embodiment The flowchart which shows the example of a procedure of the server side proxy which concerns on the same embodiment The flowchart which shows the example of a procedure of the client side proxy which concerns on the same embodiment The flowchart which shows the example of a procedure of the client side proxy which concerns on the same embodiment The flowchart which shows an example of the process sequence of the differential compression of the embodiment The flowchart which shows the other example of the process sequence of the differential compression of the embodiment The flowchart which shows the example of a procedure of the server side proxy which concerns on the same embodiment The flowchart which shows the example of a procedure of the client side proxy which concerns on the same embodiment The figure for demonstrating the data transfer between the server side proxy and client side proxy which concern on the embodiment The figure for demonstrating the data transfer between the server side proxy and client side proxy which concern on the embodiment The figure for demonstrating the data transfer between the server side proxy and client side proxy which concern on the embodiment The figure which shows the other structural example of a proxy in the embodiment The flowchart which shows the other example of a procedure of the client side proxy which concerns on the same embodiment The flowchart which shows the other example of a procedure of the client side proxy which concerns on the same embodiment The flowchart which shows the other example of a procedure of the server side proxy which concerns on the same embodiment The flowchart which shows the other example of a procedure of the server side proxy which concerns on the same embodiment The figure which shows the further another structural example of the computer network system which concerns on the embodiment Diagram for explaining a conventional computer network system The figure which shows the specific example of the message of the format of Fig.14 (a) The figure which shows the specific example of the message of the format of FIG.14 (b) The figure which shows the specific example of the message of the format of FIG.14 (c), FIG.15 (c) The figure which shows the specific example of the message of the format of FIG.14 (d) The figure which shows the specific example of the message of the format of Fig.15 (a) The figure which shows the specific example of the message of the format of FIG.15 (b) The figure which shows the example of the message of the format of FIG. The figure which shows the specific example of the message of the format of Fig.17 (a) The figure which shows the specific example of the message of the format of FIG.17 (b) The figure which shows the specific example of the message of the format of FIG.17 (c) The figure which shows the specific example of the message of the format of Fig.18 (a) The figure which shows the specific example of the message of the format of FIG.18 (b) The figure which shows the specific example of the message of the format of FIG.18 (c). The figure which shows the specific example of the message of the format of FIG.18 (d)

Explanation of symbols

202 ... ASP server center, 204 ... user office, 212 ... ASP server center LAN, 214 ... WAN, 216 ... user office LAN, 220 ... server device,
230 ... Server side proxy device, 240 ... Client side proxy device, 250 ... Client device, 231, 241 ... Reception unit, 232, 242 ... Processing unit, 233, 243 ... Transmission unit, 234, 244 ... Fingerprint cache, 2321 , 2421 ... FP compression determination unit, 2322, 2422 ... fingerprint cache management unit, 2323 ... FP compression processing unit, 2423 ... FP decompression processing unit, 2324 ... differential compression processing unit, 2424 ... differential decompression processing unit, 2325, 2425 ... FP decompression / decompression processing unit, 2326, 2426 ... Differential decompression / decompression processing unit

Claims (22)

A server-side proxy device that receives data transmitted from a server device and transmits the data to a client-side proxy device that communicates with the client device that is the destination,
Receiving means for receiving the data from the server device;
Fingerprint generating means for generating a fingerprint of the data received by the receiving means;
Holding means for holding the data received by the receiving means as reference data and holding the fingerprint generated by the fingerprint generating means based on the reference data as a fingerprint cache in association with the reference data; ,
First determination means for determining whether the fingerprint generated by the fingerprint generation means based on the data received by the reception means is held in the fingerprint cache;
When the first determination means determines that the fingerprint is not held in the fingerprint cache, for each part or part of the data received by the reception means, Among the reference data held in the fingerprint cache, it is possible to identify a fingerprint associated with reference data including the same content as the portion and a location where the same content exists in the reference data Differential compression including compression information obtained from a set of location information to be performed, and the compression information and direct designation information indicating the remaining contents excluding a portion corresponding to the compression information from the data received by the receiving unit Differential compression processing means for generating expression data;
For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data Second determination means for determining whether or not the value indicating the degree is equal to or greater than a reference value;
When the first determining unit determines that the fingerprint is held in the fingerprint cache when the receiving unit receives the data, the data of the original data of the fingerprint is stored. Instead, the compressed fingerprint data including the fingerprint is transmitted to the client-side proxy device as the destination client device, and the first fingerprint is not held in the fingerprint cache. When the determination means determines, when the second determination means determines that the value indicating the degree of compression of the differential compression expression data generated by the differential compression processing means is greater than or equal to the reference value The fingerprint and the data that was the source of the fingerprint. In addition, the client adds the data at the time of differential compression including the differential compression expression data instead of the data that was the source of the differential compression expression data to the client device as the destination. When the second determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression expression data transmitted to the side proxy device and generated by the differential compression processing unit, the finger The client side proxy adds the uncompressed data including the received data to the client device serving as the destination by adding the print and the data that is the source of the fingerprint in association with each other to the fingerprint cache Server-side proxy, comprising: a transmission means for transmitting to the apparatus Apparatus.   When transmitting the differential compression data or the non-compression data, the transmission means includes at least one of the differential compression data and the non-compression data in the differential compression data. The fingerprint of the data that was the source of the differential compression expression data included in the data at the time of differential compression is added, and the fingerprint of the data included in the data at the time of non-compression is added to the data at the time of non-compression. The server-side proxy device according to claim 1.   When transmitting the differential compression data or the non-compression data, the transmission means transmits the differential compression data and the non-compression data without adding the fingerprint. The server side proxy apparatus of Claim 1 characterized by these.   The differential compression expression data included in the differential compression data includes, as the compression information, the fingerprint corresponding to one or a plurality of the reference data, and the offset and length of the content to be copied from each reference data. In addition to the compressed information and the direct designation information, the content information copied from the reference data and information indicating the connection method of the content indicated by the direct designation information are included. The server-side proxy device according to claim 1, wherein   The differential compression representation data included in the differential compression data includes, as the compression information, the fingerprint corresponding to one reference data, and the data that is the source of the differential compression representation data among the reference data, 2. The server-side proxy device according to claim 1, wherein the server-side proxy device includes location information indicating a different portion, and includes the contents to be inserted into the different portion as the direct designation information.   The server-side proxy device according to claim 1, wherein the server-side proxy device is connected to the server device via a local area network.   The data received from the server device is transmitted by the server device as a reply to request data transmitted by the client device and transferred to the server device via the client-side proxy device and the server-side proxy device. The server-side proxy device according to claim 1, wherein the server-side proxy device is reply data. A client-side proxy device that receives data transmitted from a server device via a server-side proxy device and transmits the data to a destination client device,
Holding means for holding the data as reference data and the fingerprint of the reference data in association with the reference data as a client-side fingerprint cache;
The server side proxy device designates the fingerprint compression data including the fingerprint of the data instead of the data, one part or a plurality of parts of the data instead of the data for each part. , Compression information consisting of a set of fingerprints of reference data including the same content as the part, and location information that makes it possible to specify a location where the same content exists in the reference data, and the compression information from the data Receiving means for receiving differential compression data including differential compression expression data including direct designation information indicating the remaining content excluding the portion corresponding to the data, or uncompressed data including the data;
Type determination means for determining whether the data received by the receiving means is the fingerprint compression data, the differential compression data, or the non-compression data;
When the type determining means determines that the receiving means has received the differential compression time data, the differential compression expression data included in the differential compression data included in the differential compression data is the source of the differential compression expression data With reference to a set of the fingerprint and the location information included in the compression information corresponding to the portion in the data, for each portion, the fingerprint and the location information are obtained from the client-side fingerprint cache. The same content as the part is acquired, and the original data of the differential compressed expression data is restored using the same content as the acquired part and the direct designation information included in the differential compressed expression data. Restoration processing means,
Data stored in the client-side fingerprint cache in association with a fingerprint included in the compressed data when the type determining unit determines that the receiving unit has received the fingerprint compression data. Is transmitted to the client device serving as the destination, and when the type determination unit determines that the reception unit has received the differential compression data, the restoration processing unit includes the differential compression data in the differential compression data Data restored based on the differentially compressed representation data to be added to the client-side fingerprint cache in association with the fingerprint generated based on the data, and the data as the destination client And the receiving means receives the uncompressed data. And when the type determination means determines, the data included in the uncompressed data is added to the client-side fingerprint cache in association with the fingerprint generated based on the data, and Transmission means for transmitting the data to the client device as the destination,
The server side proxy device is:
Means for receiving the data from the server device;
Means for generating a fingerprint of the received data;
As reference data the data which said means for receiving receives, means for holding the fingerprint means has generated said generated based on the reference data, as a server-side fingerprint cache in association with said reference data,
If the fingerprint generated based on the received data is not held in the server-side fingerprint cache, for each part or parts of the received data, Among the reference data held in the server-side fingerprint cache, the fingerprint associated with the reference data including the same contents as the part and the location where the same contents exist in the reference data are specified. Compression information consisting of a set of possible location information is obtained, and includes the compression information and direct designation information indicating the remaining contents excluding the portion corresponding to the compression information from the data received by the receiving means Differential compression processing means for generating differential compressed expression data;
For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data A difference expression availability determination unit that determines whether or not a value indicating the degree is equal to or greater than a reference value;
When the fingerprint generated based on the data is stored in the server-side fingerprint cache when the data is received, the fingerprint is used instead of the data that is the source of the fingerprint. When the fingerprint compression data including print is transmitted to the client side proxy device as the destination client device, and the fingerprint is not held in the server side fingerprint cache, the differential compression is performed. When the differential representation availability determination unit determines that the value indicating the degree of compression is greater than or equal to the reference value for the differential compression representation data generated by the processing unit, the fingerprint and the source of the fingerprint are the same. The server-side finger The data at the time of differential compression that is added to the print cache and includes the differential compression representation data instead of the data that was the source of the differential compression representation data is sent to the client side proxy device as the destination of the client device When the differential representation availability determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression representation data transmitted and generated by the differential compression processing unit, the fingerprint and the fingerprint The data that was the source of printing is associated with the data and added to the server-side fingerprint cache, and uncompressed data including the received data is sent to the client-side proxy device as the destination client device. features and to torque client side flop that is one having a means for transmitting Carboxymethyl apparatus. Based on the data restored by the decompression processing unit based on the differential compression expression data included in the differential compression data when the type determination unit determines that the reception unit has received the differential compression data. Generating a fingerprint of the data, and when the type determining unit determines that the receiving unit has received the uncompressed data, the fingerprint of the data is based on the data included in the uncompressed data. A fingerprint generating means for generating a print;
For the received data at the time of differential compression, the transmission means restores the data restored by the restoration processing means based on the differential compression expression data included in the data at the time of differential compression, and the fingerprint generation means based on the data Is added to the client-side fingerprint cache in association with the generated fingerprint, and for the received uncompressed data, the fingerprint generation means generates the data included in the uncompressed data based on the data 9. The client side proxy device according to claim 8, wherein the client side proxy device is added to the client side fingerprint cache in association with the fingerprint. The differential compression time data received by the receiving unit includes a fingerprint generated based on the data that was the source of the differential compression expression data included in the differential compression time data,
The client-side proxy device, when the type determining unit determines that the receiving unit has received the uncompressed data, performs a fingerprint of the data based on the data included in the uncompressed data. Further comprising a fingerprint generating means for generating,
For the received data at the time of differential compression, the transmitting means converts the data restored by the restoration processing means based on the differential compression expression data included in the data at the time of differential compression, to the fingerprint included in the data at the time of differential compression Add to the client-side fingerprint cache in association with, for said received uncompressed data, the data contained in data uncompressed, the fingerprint fingerprint generating unit has generated based on the data 9. The client side proxy device according to claim 8, wherein the client side proxy device is associated and added to the client side fingerprint cache. The uncompressed data received by the receiving means includes a fingerprint generated based on the data included in the uncompressed data,
The client-side proxy device, when the type determining unit determines that the receiving unit has received the differential compression data, the restoration processing unit based on differential compression expression data included in the differential compression data Further comprising fingerprint generation means for generating a fingerprint of the data based on the data restored by
For the received data at the time of differential compression, the transmission means regenerates the data restored by the restoration processing means based on the differential compression expression data included in the data at the time of differential compression, and generates fingerprints based on the data. Is added to the client-side fingerprint cache in association with the generated fingerprint, and for the received uncompressed data, the data is associated with the fingerprint included in the uncompressed data in the client-side 9. The client side proxy device according to claim 8, wherein the client side proxy device is added to a fingerprint cache. The differential compression time data received by the receiving unit includes a fingerprint generated based on the data that was the source of the differential compression expression data included in the differential compression time data,
The uncompressed data received by the receiving means includes a fingerprint generated based on the data included in the uncompressed data,
For the received data at the time of differential compression, the transmitting means converts the data restored by the restoration processing means based on the differential compression expression data included in the data at the time of differential compression, to the fingerprint included in the data at the time of differential compression Add to the client-side fingerprint cache in association with, for said received uncompressed data, adds the data to the client-side fingerprint cache in association with the fingerprint included in data uncompressed the client-side proxy device according to claim 8, characterized in that. The fingerprint compression data includes identification information indicating that it is fingerprint compression data, and the differential compression data includes identification information indicating that it is differential compression data. The uncompressed data includes identification information indicating that it is uncompressed data,
9. The client side proxy device according to claim 8, wherein the type determination unit performs the determination based on the identification information. The fingerprint compression data includes the fingerprint in its header, its body is NULL, and the differential compression data includes a differential compression flag in its header indicating that it is differential compression data. The differentially compressed representation data is included in the body, and neither the header nor the body includes the fingerprint, and the uncompressed data indicates that it is uncompressed data. An uncompressed flag is included in the header, the data is included in the body, and neither the header nor the body includes the fingerprint.
The type determining unit determines that the data received by the receiving unit is the data at the time of fingerprint compression when it is detected that the fingerprint is included in the header or the body is NULL. When the differential compression flag is detected in the header, it is determined that the data received by the reception unit is the data at the time of differential compression, and when the non-compression flag is detected in the header, the reception unit data but received by the client-side proxy device according to claim 8, characterized in that it is determined that the an uncompressed data. The differential compression expression data included in the differential compression data includes, as the compression information, the fingerprint corresponding to one or a plurality of the reference data, and the offset and length of the content to be copied from each reference data. In addition to the compressed information and the direct designation information, the content information copied from the reference data and information indicating the connection method of the content indicated by the direct designation information are included. The client-side proxy device according to claim 8, wherein: The differential compression representation data included in the differential compression data includes, as the compression information, the fingerprint corresponding to one reference data, and the data that is the source of the differential compression representation data among the reference data, 9. The client side proxy device according to claim 8, wherein the client side proxy device includes location information indicating a different portion, and the direct designation information includes contents to be fitted into the different portion. 9. The client side proxy device according to claim 8, wherein the client side proxy device is connected to the client device via a local area network. The data received from the server device is transmitted by the server device as a reply to request data transmitted by the client device and transferred to the server device via the client-side proxy device and the server-side proxy device. the client-side proxy device according to any one of claims 8 to 17 characterized in that it is a reply data. Receives data transmitted from the server device, transmits the data to a client-side proxy device that communicates with the client device that is the destination, and uses the data as reference data, the fingerprint of the reference data, A data transfer method for a server-side proxy device comprising holding means for holding as a fingerprint cache in association with reference data,
Receiving the data from the server device;
Generate a fingerprint of the received data;
Determining whether the fingerprint generated based on the received data is held in the fingerprint cache;
When it is determined that the fingerprint is not held in the fingerprint cache, one or more portions of the received data are held in the fingerprint cache for each portion. Compressed information comprising a set of fingerprints associated with reference data including the same content as the portion of the reference data and location information that makes it possible to identify the location where the same content exists in the reference data And generating differential compression representation data including the compression information and direct designation information indicating the remaining contents excluding the portion corresponding to the compression information from the received data,
For the data amount of the generated differential compressed representation data, a value indicating the degree of compression calculated by the data amount of the data that was the source of the differential compressed representation data and the data amount of the differential compressed representation data is , Determine whether it is above the reference value,
When the data is received, if it is determined that the fingerprint is held in the fingerprint cache, the fingerprint compression including the fingerprint instead of the data that is the source of the fingerprint If the time data is transmitted to the client-side proxy device as the destination client device and it is determined that the fingerprint is not held in the fingerprint cache, the generated differential compression representation When it is determined that the value indicating the degree of compression of the data is equal to or greater than the reference value, the fingerprint is associated with the original data of the fingerprint and added to the fingerprint cache; And the source of the differential compression expression data. Data at the time of differential compression including the differential compression representation data instead of data is transmitted to the client side proxy device as the destination client device, and the degree of compression is indicated for the generated differential compression representation data When it is determined that the value is not equal to or greater than the reference value, the fingerprint is associated with the original data of the fingerprint, added to the fingerprint cache, and uncompressed including the received data A data transfer method comprising transmitting time data to the client side proxy device as the destination client device. The data transmitted from the server device is received via the server-side proxy device, and the data is transmitted to the client device that is the destination, and the fingerprint of the reference data is used as the reference data. A data transfer method for a client-side proxy device comprising holding means for holding as a client-side fingerprint cache in association with the reference data,
The server side proxy device designates the fingerprint compression data including the fingerprint of the data instead of the data, one part or a plurality of parts of the data instead of the data for each part. , Compression information consisting of a set of fingerprints of reference data including the same content as the part, and location information that makes it possible to specify a location where the same content exists in the reference data, and the compression information from the data Receiving differential compression data including differential compression expression data including direct designation information indicating the remaining contents excluding the portion corresponding to, or uncompressed data including the data,
Determining whether the received data is the fingerprint compression data, the differential compression data, or the uncompressed data;
When it is determined that the differential compression time data has been received, the compression corresponding to the portion of the original data of the differential compression representation data included in the differential compression representation data included in the differential compression time data Referring to the set of the fingerprint and location information included in the information, the same content as that portion is obtained from the client-side fingerprint cache based on the fingerprint and location information for each portion. Then, using the same content as the acquired part and the direct designation information included in the differential compression expression data, the original data of the differential compression expression data is restored,
The fingerprint when the compressed time data is determined to be received, the data in association with the fingerprint that is included in the compressed data held in the client-side fingerprint cache, serving as the destination the client device When it is determined that the data at the time of differential compression has been received, the data restored based on the differential compression expression data included in the data at the time of differential compression is generated based on the data When it is determined that the uncompressed data has been received by adding the data to the client-side fingerprint cache in association with the fingerprint and transmitting the data to the destination client device. Before the data included in the uncompressed data is generated based on the data In association with the fingerprint in addition to the client-side fingerprint cache, and, the data is shall be transmitted to the said destination said client device,
The server side proxy device is:
Means for receiving the data from the server device;
Means for generating a fingerprint of the received data;
Means for holding, as reference data, the data received by the means for receiving, the fingerprint generated by the means for generating based on the reference data as a server side fingerprint cache in association with the reference data;
If the fingerprint generated based on the received data is not held in the server-side fingerprint cache, for each part or parts of the received data, Among the reference data held in the server-side fingerprint cache, the fingerprint associated with the reference data including the same contents as the part and the location where the same contents exist in the reference data are specified. Compression information consisting of a set of possible location information is obtained, and includes the compression information and direct designation information indicating the remaining contents excluding the portion corresponding to the compression information from the data received by the receiving means Differential compression processing means for generating differential compressed expression data;
For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data A difference expression availability determination unit that determines whether or not a value indicating the degree is equal to or greater than a reference value;
When the fingerprint generated based on the data is stored in the server-side fingerprint cache when the data is received, the fingerprint is used instead of the data that is the source of the fingerprint. When the fingerprint compression data including print is transmitted to the client side proxy device as the destination client device, and the fingerprint is not held in the server side fingerprint cache, the differential compression is performed. When the differential representation availability determination unit determines that the value indicating the degree of compression is greater than or equal to the reference value for the differential compression representation data generated by the processing unit, the fingerprint and the source of the fingerprint are the same. The server-side finger The data at the time of differential compression that is added to the print cache and includes the differential compression representation data instead of the data that was the source of the differential compression representation data is sent to the client side proxy device as the destination of the client device When the differential representation availability determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression representation data transmitted and generated by the differential compression processing unit, the fingerprint and the fingerprint The data that was the source of printing is associated with the data and added to the server-side fingerprint cache, and uncompressed data including the received data is sent to the client-side proxy device as the destination client device. data transfer wherein the this and has a means for transmitting. A program for causing a computer to function as a server-side proxy device that receives data transmitted from a server device and transmits the data to a client-side proxy device that communicates with the client device that is the destination,
Receiving means for receiving the data from the server device;
Fingerprint generating means for generating a fingerprint of the data received by the receiving means;
Holding means for holding the data received by the receiving means as reference data and holding the fingerprint generated by the fingerprint generating means based on the reference data as a fingerprint cache in association with the reference data; ,
First determination means for determining whether the fingerprint generated by the fingerprint generation means based on the data received by the reception means is held in the fingerprint cache;
When the first determination means determines that the fingerprint is not held in the fingerprint cache, for each part or part of the data received by the reception means, Among the reference data held in the fingerprint cache, it is possible to identify a fingerprint associated with reference data including the same content as the portion and a location where the same content exists in the reference data Differential compression including compression information obtained from a set of location information to be performed, and the compression information and direct designation information indicating the remaining contents excluding a portion corresponding to the compression information from the data received by the receiving unit Differential compression processing means for generating expression data;
For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data Second determination means for determining whether or not the value indicating the degree is equal to or greater than a reference value;
When the first determining unit determines that the fingerprint is held in the fingerprint cache when the receiving unit receives the data, the data of the original data of the fingerprint is stored. Instead, the compressed fingerprint data including the fingerprint is transmitted to the client-side proxy device as the destination client device, and the first fingerprint is not held in the fingerprint cache. When the determination means determines, when the second determination means determines that the value indicating the degree of compression of the differential compression expression data generated by the differential compression processing means is greater than or equal to the reference value The fingerprint and the data that was the source of the fingerprint. In addition, the client adds the data at the time of differential compression including the differential compression expression data instead of the data that was the source of the differential compression expression data to the client device as the destination. When the second determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression expression data transmitted to the side proxy device and generated by the differential compression processing unit, the finger The client side proxy adds the uncompressed data including the received data to the client device serving as the destination by adding the print and the data that is the source of the fingerprint in association with each other to the fingerprint cache Pro for operating a computer as a transmission means for transmitting to a device Lamb. A program for causing a computer to function as a client-side proxy device that receives data transmitted from a server device via a server-side proxy device and transmits the data to a destination client device,
The program is
Holding means for holding the data as reference data and the fingerprint of the reference data in association with the reference data as a client-side fingerprint cache;
The server side proxy device designates the fingerprint compression data including the fingerprint of the data instead of the data, one part or a plurality of parts of the data instead of the data for each part. , Compression information consisting of a set of fingerprints of reference data including the same content as the part, and location information that makes it possible to specify a location where the same content exists in the reference data, and the compression information from the data Receiving means for receiving differential compression data including differential compression expression data including direct designation information indicating the remaining content excluding the portion corresponding to the data, or uncompressed data including the data;
Type determination means for determining whether the data received by the receiving means is the fingerprint compression data, the differential compression data, or the non-compression data;
When the type determining means determines that the receiving means has received the differential compression time data, the differential compression expression data included in the differential compression data included in the differential compression data is the source of the differential compression expression data based with reference to the set of the said fingerprint with the location information the compressed information corresponding to the portion in the data includes, for each said portion, the fingerprint and the location information from the client-side fingerprint cache The same content as the part is acquired, and the original data of the differential compressed expression data is restored using the same content as the acquired part and the direct designation information included in the differential compressed expression data. Restoration processing means,
Data stored in the client-side fingerprint cache in association with a fingerprint included in the compressed data when the type determining unit determines that the receiving unit has received the fingerprint compression data. Is transmitted to the client device serving as the destination, and when the type determination unit determines that the reception unit has received the differential compression data, the restoration processing unit includes the differential compression data in the differential compression data Data restored based on the differentially compressed representation data to be added to the client-side fingerprint cache in association with the fingerprint generated based on the data, and the data as the destination client And the receiving means receives the uncompressed data. If, when the type determination means determines the data contained in data uncompressed, in association with the fingerprint generated based on the data added to the client-side fingerprint cache, and, For causing the computer to function as transmission means for transmitting the data to the client device as the destination ;
The server side proxy device is:
Means for receiving the data from the server device;
Means for generating a fingerprint of the received data;
Means for holding, as reference data, the data received by the means for receiving, the fingerprint generated by the means for generating based on the reference data as a server side fingerprint cache in association with the reference data;
If the fingerprint generated based on the received data is not held in the server-side fingerprint cache, for each part or parts of the received data, Among the reference data held in the server-side fingerprint cache, the fingerprint associated with the reference data including the same contents as the part and the location where the same contents exist in the reference data are specified. Compression information consisting of a set of possible location information is obtained, and includes the compression information and direct designation information indicating the remaining contents excluding the portion corresponding to the compression information from the data received by the receiving means Differential compression processing means for generating differential compressed expression data;
For the data amount of the differential compression representation data generated by the differential compression processing means, the compression amount calculated by the data amount of the data that was the source of the differential compression representation data and the data amount of the differential compression representation data A difference expression availability determination unit that determines whether or not a value indicating the degree is equal to or greater than a reference value;
When the fingerprint generated based on the data is stored in the server-side fingerprint cache when the data is received, the fingerprint is used instead of the data that is the source of the fingerprint. When the fingerprint compression data including print is transmitted to the client side proxy device as the destination client device, and the fingerprint is not held in the server side fingerprint cache, the differential compression is performed. When the differential representation availability determination unit determines that the value indicating the degree of compression is greater than or equal to the reference value for the differential compression representation data generated by the processing unit, the fingerprint and the source of the fingerprint are the same. The server-side finger The data at the time of differential compression that is added to the print cache and includes the differential compression representation data instead of the data that was the source of the differential compression representation data is sent to the client side proxy device as the destination of the client device When the differential representation availability determination unit determines that the value indicating the degree of compression is not equal to or greater than the reference value for the differential compression representation data transmitted and generated by the differential compression processing unit, the fingerprint and the fingerprint The data that was the source of printing is associated with the data and added to the server-side fingerprint cache, and uncompressed data including the received data is sent to the client-side proxy device as the destination client device. program, characterized in that those having a means for transmitting.

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