JP3943867B2 - Server-side proxy, data transfer method and program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a server-side proxy that performs data transfer for other devices, a data transfer method, and a program.
[0002]
[Prior art]
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, a WORLD WIDE WEB system (or simply referred to as WEB) composed of a WEB server and a client communicating with each other 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.
[0003]
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.
[0004]
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.
[0005]
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.
[0006]
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.
[0007]
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”.
[0008]
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”.
[0009]
As a request message method, there are a “GET method” for reading information on the server, a “PUT method” for writing data held by the user to the server, and a “POST method” for sending back the result of processing in response to the request. It is the main thing used to access services. In addition, a method such as DELETE is defined.
[0010]
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.
[0011]
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.
[0012]
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.
[0013]
Since the PUT method sends data to the server, the cache does nothing.
[0014]
[Problems to be solved by the invention]
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.
[0015]
However, as a system in which a user accesses information and services on a server via a network using a WEB browser, such as WEB-based ASP (Application Service Provider), the 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.
[0016]
  The present invention has been made in consideration of the above circumstances, and a server-side proxy having a cache technology and a compression technology that can further reduce the load on the network connecting the server-side proxy and the client-side proxy, It is an object to provide a data transfer method and program.
[0017]
[Means for Solving the Problems]
  The present inventionThe server apparatus receives a plurality of request data transmitted from each of the plurality of client apparatuses to the server apparatus and relayed to each of the client side proxies in charge of access to the server apparatuses of the plurality of client apparatuses. As a reply to each of the plurality of request dataFrom the deviceTo each of the client devicesSendReplydataServer-side proxy that forwards each to the client-side proxy that is the proxy for the client device that is the destination of the reply dataBecauseReply that is a reply to each request data transferred from each of multiple client side proxiesdataRespectivelyTheFrom the server deviceReceiveFurther, it also receives reply data that is a reply to request data transferred from a client-side proxy among the plurality of client-side proxies.Receiving means forFingerprint generation means for generating a fingerprint of each of the reply data, and further generating a fingerprint that is a fingerprint of the reply data;GenerationEach of the fingerprints associated with each of the original reply data is a proxy on the client side that is a proxy for each client device that is the destination of the reply data.Every,As a fingerprint cache for each client-side proxyHoldRuhoHolding means,Determining means for determining whether or not the fingerprint is held in a fingerprint cache for each client-side proxy corresponding to a client-side proxy that is a proxy of a client device that is the destination of the reply data; The fingerprint is the client-side proxyCorresponding toClient-side per-proxy fingerprint cacheHeld inAnd determined by the determining meansIn case, Said certain replyInstead of dataThe fingerprintTheTo the client side proxy addressed to the client deviceSendAnd the fingerprint is the proxy on the client side.Corresponding toClient-side per-proxy fingerprint cacheNot held inAnd determined by the determining meansIn caseThe fingerprint and the replydataAnd relatedAttached toThe client-side proxyCorresponding toAdd to the client side per-proxy fingerprint cache andDataTo the client side proxy addressed to the client deviceSendSendingAnd a communication means.
[0021]
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.
[0022]
  According to the present invention,Server device~ sideServer-side proxyIsClient device~ sideAfter the request data issued from the client side proxy provided to the server device to the server device is transferred to the server device, the request to the request data issued by the server device to the client device is transferred. When reply data that is a reply is received and transferred to the proxy on the client side,dataFingerprint generated fromTheIn association with the reply data, a fingerprint cache for each client-side proxy corresponding to the client-side proxy associated with the client device that is the destination of the reply dataRetentionFrom the server device.dataIs received in the fingerprint cache for each client-side proxy corresponding to the client-side proxy associated with the client device that is the destination of the reply data.RetentionIsingreplyFor data,The replyRespond instead of transferring dataFingerprintBy transferringBetween the server-side proxy and the client-side proxyThe amount of data transferred between them can be reduced. Also,Server-side proxyWhenClient-side proxyAre connected one-to-many,Server-side proxyIsClient-side proxyEveryreplyData and itsMaintains a per-proxy fingerprint cache cache associated with a fingerprintBecause there isreplyAbout dataIn the fingerprint cache for each client-side proxy corresponding to the client-side proxy related to the destination client deviceThereplyData and itsFingerprintCorrespondence withThe client-side proxy if it is not maintainedInforThe relevantreplyInstead of dataFingerprintWill be transferredYou can avoid that.
[0023]
  Further, according to the present invention, for example, even if the reply message of the GET method is private data, it is compressed by the fingerprint.Between the client-side proxy and the server-side proxyWill be able to transfer between. Also, for example, even if the reply message of the GET method is dynamic data, if the content is the same, compress this with a fingerprint.Between the client-side proxy and the server-side proxyWill be able to transfer between. Also, for example, even with the POST method, if the result is the same data, compress this with a fingerprint.Between the client-side proxy and the server-side proxyWill be able to transfer between.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings.
[0025]
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.
[0026]
FIG. 22 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) 14 such as the Internet or a dedicated line is connected between a local area network (LAN) 12 in the ASP server center 2 and a local area network (LAN) 16 in the user office 4. The server 20 in the ASP server center 2 and the client 50 in the user office 4 can communicate with each other via the LAN 12, the WAN 14, and the LAN 16. One or more servers are connected to the ASP server center LAN, and one or more clients are connected to the user office LAN.
[0027]
The WEB-based ASP provides services based on various application programs from the server 20 installed in the server center 2 via the WAN 14, and the user uses the WEB browser on the client installed in the office 4. Access the service.
[0028]
A plurality of ASP server centers 2 and user offices 4 may exist.
[0029]
In such a usage mode, the effective communication capacity (bandwidth) of the network connecting the user office LAN 16 and the server center LAN 12, particularly the wide area network 14 such as the Internet, is the server center LAN 12 or the user office LAN 16. 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.
[0030]
Therefore, in this embodiment, as shown in FIG. 1, two modules, a server-side proxy 30 and a client-side proxy 40, are installed at both ends of the wide area network 14 that connects the server center LAN 12 and the user office LAN 16. By performing fingerprint compression (FP compression) described later between them to reduce the amount of communication data, the bottleneck of the wide area network is eliminated.
[0031]
Here, a case is considered in which FP compression is applied to communication between one server-side proxy 30 and a plurality of client-side proxies 40 (one client-side proxy 40 is one server at a certain time). Suppose that communication is performed with the side proxy 30 using FP compression).
[0032]
The server 20, the server-side proxy 30, the client-side proxy 40, and the client 50 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 in the computer, driver software, software for packet communication, encryption software, etc., or hardware such as a communication interface device, an external storage device, an input / output device, etc. Connected. 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.
[0033]
On the client 50 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.
[0034]
A predetermined server program operates on the server 20 and provides services specific to the server site to the user of the client 50.
[0035]
As shown in FIG. 1, the server-side proxy 30 is connected to both the intra-server center LAN 12 and the WAN 14 and can be installed and operated so as to operate as a transparent proxy. Further, as shown in FIG. 2, it can be installed on the LAN 12 in the server center. Further, as shown in FIG. 3, the server-side proxy 30 can be implemented so as to be built in the server 20.
[0036]
Similarly, as shown in FIG. 1, the client-side proxy 40 can be installed and implemented so as to connect to both the intra-user office LAN 16 and the WAN 14 and operate as a transparent proxy. Further, as shown in FIG. 2, it can be installed on the LAN 16 in the user office. Further, as shown in FIG. 3, the function of the client side proxy 40 can be implemented in a browser or the like that operates on the client 50. Alternatively, the client-side proxy 40 for personal use may be operated on the client 50 that operates such as a browser.
[0037]
Each server-side proxy 30 and each client-side proxy 40 may all have the same form as shown in FIGS. Further, for example, a certain server-side proxy 30 is in the form of FIG. 1, a certain server-side proxy 30 is in the form of FIG. 2, a certain client-side proxy 40 is in the form of FIG. 1, and a certain client-side proxy 40 is in the form of FIG. Thus, different forms may be mixed.
[0038]
The client-side proxy 40 may be built in a mobile terminal or a mobile computer. FIG. 4 shows an example of this case.
[0039]
The server side proxy 30 and the client side proxy 40 of this embodiment both 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).
[0040]
As illustrated in FIG. 5, the fingerprint is determined by a predetermined calculation method (hash function in the example of FIG. 5) from the contents of data exchanged by the HTTP protocol (content in the example of FIG. 5). 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.
[0041]
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).
[0042]
As shown in FIG. 6, the fingerprint cache (60 in the figure) of the server-side proxy 30 and the client-side proxy 40 has a data body (61 in the figure) exchanged by the HTTP protocol in the past as its data. The fingerprint value (62 in the figure) calculated from the above is recorded and managed as a name. As will be described in detail later, the server-side proxy 30 manages the correspondence between the fingerprint and the data for each client-side proxy 40 that is a partner that performs communication to which FP compression is applied.
[0043]
For example, when transferring data from the server-side proxy 30 to the client-side proxy 40 using the HTTP protocol, the server-side proxy 30 calculates a fingerprint of the data, and the data corresponding to the fingerprint is the client-side proxy. If it is in the fingerprint cache corresponding to 40, the data (data having the same contents) has been transferred to the client-side proxy 40 in the past. The fingerprint value to be transferred is transferred. The client-side proxy 40 that has received the fingerprint can reproduce the data to be transferred by taking out 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.
[0044]
The server-side proxy 30 can specify the client-side proxy 40 to which data received from the server 20 should be transferred, for example, according to a predetermined communication protocol.
[0045]
Further, the client-side proxy 40 has a configuration in which a fingerprint is described in the message from the server-side proxy 30 and uses the described fingerprint at the time of registration, and the message in the message from the server-side proxy 30 There are a configuration in which the fingerprint is not described in the server and the fingerprint is calculated by itself, and a configuration in which the fingerprint is described in a message from the server-side proxy 30 and the fingerprint is calculated again.
[0046]
For explanation, when transferring data between the server-side proxy 30 and the client-side proxy 40, 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).
[0047]
In addition, between the server-side proxy 30 and the client-side proxy 40, an object to which FP compression is applied to all messages (that is, an object to perform 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.
The setting contents regarding the application target of such FP compression include, for example, a method of making the same throughout the system, a method of deciding for each pair of the server side proxy 30 and the client side proxy 40, and the like. In the latter case, there are a method of setting in advance and a method of setting for each session.
[0048]
Next, an inter-proxy message format (for a message to which FP compression is applied) when data is transferred between the server-side proxy 30 and the client-side proxy 40 will be described with reference to FIGS. .
[0049]
Messages that are not subject to FP compression may be transferred between proxies in the message format (when received by the proxy on the FP compression side (transmission side)) without doing anything for FP compression. Absent. Alternatively, the proxy on the FP compression side (transmission side) can transfer the message header, for example, with information that makes it possible to identify that the message is not subject to FP compression.
[0050]
When data is transferred between the server-side proxy 30 and the client-side proxy 40, the message to which FP compression is applied includes a message (a message at the time of compression) in which data is FP-compressed and replaced with a fingerprint. , There is a message that is not FP-compressed and data is loaded (message when uncompressed).
[0051]
The uncompressed message format is used when the data included in the message is not registered in the fingerprint cache of the server-side proxy 30 corresponding to the client-side proxy 40 that is the transfer destination. On the other hand, the message format at the time of compression is used when the data included in the message is registered in the fingerprint cache of the server-side proxy 30 corresponding to the client-side proxy 40 that is the transfer destination.
[0052]
On the decompression side (reception side), the data can be registered in the fingerprint cache when the uncompressed format message is received.
[0053]
FIG. 7 shows an example of the message format. (A) is an uncompressed message, and (b) is a compressed message.
[0054]
In (a), data is placed in the message body, and in (b), a fingerprint (FP) is placed in the message body instead of data. Further, in this example, identification information that enables identification of the presence or absence of FP compression is described in the message header (in the compression proxy), and whether or not FP compression is performed based on this identification information (in the decompression proxy) (For example, 0 means no compression, 1 means 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.
[0055]
At the time of non-compression, the fingerprint is not included in the message in the example of FIG. 7A, but the message body may include the fingerprint in addition to the data, or FIG. As shown, the message header may include a fingerprint. 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.
[0056]
If there is a message that is not subject to FP compression, the decompression side (reception side) determines whether the message is subject to FP compression depending on whether or not the identification information is included in the message header. It is also possible to determine whether the message is not applicable. Also, identification information may be provided in a header of a message that is not subject to FP compression, and three types of messages may be identified based on the identification information (for example, 01 is not applicable, and 10 is applicable (applicable). And) no compression, 11 (applicable and) with compression).
[0057]
FIG. 9 shows another example of the message format. (A) is an uncompressed message, and (b) is a compressed message. In (a), data is put on the message body, and in (b), the message body is null. In this example, the fingerprint (FP) is described in the message header in both (a) and (b). The identification information that can identify the presence or absence of FP compression is the same as in the above example.
[0058]
In this case, there is a method of using a message format (format not including a fingerprint) similar to that shown in FIG.
[0059]
If there is a message that is not subject to FP compression, the proxy on the compression side (transmission side) always applies a finger to the message header that is subject to FP compression, in addition to the method based on the identification information described above. In the case of a configuration describing a print, the decompression side (reception side) can also determine whether or not a fingerprint is included in the message header.
[0060]
FIG. 10 shows still another example of the message format. (A) is an uncompressed message, and (b) is a compressed message. In (a), data is put on the message body, and in (b), the message body is null. In this example, the fingerprint (FP) is described in the message header in both (a) and (b). However, in this example, identification information that enables identification of the presence or absence of FP compression is not used.
[0061]
In this example, whether or not FP compression is performed can be identified based on whether or not the message body is null. However, if a message that is not subject to FP compression and whose message body is null may exist, for example, depending on whether a fingerprint (FP) exists in the message header, FP compression is performed. To identify whether the message is a compressed message or an FP compression not applicable message body and a null message body (or indicates whether the message header is an FP compression applicable or not applicable) Information may be provided).
[0062]
Note that there is a method of using a format that does not describe a fingerprint in a message as shown in FIG. In this case, the presence or absence of FP compression can be identified by whether or not the fingerprint is included in the message header. However, if there is a message that is not subject to FP compression, for example, information indicating whether the message is subject to FP compression or not may be provided in the message header.
[0063]
In the following, the present embodiment will be described in detail with a focus on the case where the reply data is transferred from the server-side proxy 30 to the client-side proxy 40 when the reply data is FP compressed / decompressed.
[0064]
FIG. 12 shows a configuration example of the server side proxy 30 of the present embodiment, and FIG. 13 shows a configuration example of the client side proxy 40 of the present embodiment. 12 and 13 mainly show the configuration for transferring data from the server-side proxy 30 to the client-side proxy 40. FIG.
[0065]
As shown in FIG. 12, the server-side proxy 30 includes a receiving unit 31 that performs processing for receiving a transfer message from the intra-server center LAN 12 or the wide area network 14, and performs FP compression on data included in the transfer message. A processing unit 32 for performing processing, a transmission unit 33 for performing processing for transmitting a transfer message to the LAN 12 in the server center or the wide area network 14, and a finger for associating and storing the fingerprint and the original data A print cache (FP cache) 34 is provided. In addition, the processing unit 32 is for performing search and registration with respect to the fingerprint (FP) compression determination unit 321 and the fingerprint cache 34 for determining whether or not the data included in the transfer message is to be compressed. A fingerprint cache (FP cache) management unit 322 and a fingerprint (FP) compression processing unit 323 for performing processing such as replacing data included in the transfer message with a corresponding fingerprint are included.
[0066]
Now, the FP cache management unit 322 manages the correspondence between fingerprints and data for each client-side proxy 40 that is a partner for performing communication to which FP compression is applied. Although there are various variations in the form, some of them will be described below (note that FIG. 12 shows a state in which the FP cache 34 logically corresponding to each of the client side proxies 40 is provided). .
[0067]
(1) FIG. 14 shows a configuration in which a hash table is provided for each client-side proxy 40 and data corresponding to a fingerprint is also held for each client-side proxy 40 (the same content has a copy for each client-side proxy) It is an example. In this case, the FP cache management unit 322 specifies the FP cache 34 corresponding to the client-side proxy 40 that is the data transfer destination, and determines whether or not the fingerprint corresponding to the data is held in the FP cache 34. Will be checked.
[0068]
(2) In FIG. 15, a hash table is provided for each client-side proxy 40, but only one identical content is held, and pointer information is held in the hash table (note that the client-side proxy 40 is different and has a fingerprint. If the contents of the original data are different even if the values of are the same, the respective data are retained). In this case, the FP cache management unit 322 specifies the FP cache 34 corresponding to the client-side proxy 40 that is the data transfer destination, and determines whether or not the fingerprint corresponding to the data is held in the FP cache 34. Will be checked.
[0069]
(3) FIG. 16 shows client-side proxy identification information for identifying a client-side proxy serving as a transfer destination of data corresponding to the fingerprint in the hash table instead of providing the FP cache 34 for each client-side proxy 40. Is added to form a pair of client side proxy identification information and a fingerprint value. FIG. 16 shows a configuration example in which there is only one identical content as in (2) and the pointer information is held in the hash table, but instead, as in (1), A configuration example in which data is held for each entry is also possible. The client side proxy identification information is information that can uniquely identify the client side proxy. For example, an IP address, a MAC address, a host ID, a channel identifier, or information that can uniquely identify them can be used. In this case, the FP cache management unit 322 specifies the client-side proxy identification information of the client-side proxy 40 that is the data transfer destination, and stores the client-side proxy identification information and the fingerprint corresponding to the data in the FP cache 34. It is checked whether or not the pair is held.
[0070]
(4) In FIG. 17, the FP cache 34 is not provided for each client-side proxy 40, and the client-side proxy identification information group that can use the fingerprint is stored in the hash table corresponding to the fingerprint value. This is an example of the configuration. In this case, the FP cache management unit 322 specifies the client-side proxy identification information of the client-side proxy 40 that is the data transfer destination, and whether or not the fingerprint corresponding to the data is held in the FP cache 34. It is checked whether the client side proxy identification information is held in the client side proxy identification information group for the fingerprint.
[0071]
Next, as shown in FIG. 13, the client-side proxy 40 performs processing for receiving the transfer message from the user office LAN 16 or the wide area network 14, and the data included in the transfer message. A processing unit 42 for performing FP decompression, a transmission unit 43 for performing processing for transmitting a transfer message to the user office LAN 16 or the wide area network 14, and storing fingerprints in association with the original data A fingerprint cache (FP cache) 44 is provided. In addition, the processing unit 42 applies a fingerprint (FP) compression determination unit 421 and a fingerprint cache 34 for determining whether or not the data included in the transfer message is to be compressed and whether or not the transfer message is subjected to FP compression. Fingerprint cache (FP cache) management unit 422 for performing search and registration, fingerprint (FP) for performing processing such as decompressing the original data from the fingerprint included in the FP compressed transfer message A decompression processing unit 423 is included.
[0072]
Note that the compression-side FP compression determination unit 321 and the decompression-side FP compression determination unit 421 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 321 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 421 on the side and the corresponding part of the procedure example shown later are unnecessary). In addition, the decompression-side FP compression determination unit 421 determines whether or not the data subjected to FP compression application 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).
[0073]
FIG. 18 shows an example of the processing procedure of the server-side proxy 30 from when the server-side proxy 30 receives the request message from the client-side proxy 40 until the reply message is transferred to the client-side proxy 40.
[0074]
FIG. 18 describes processing corresponding to a single request from the client-side proxy 40 of the server-side proxy 30. For example, when request messages are simultaneously received from a plurality of client-side proxies 40, Each time a request is received, the processing of FIG. 18 is performed in parallel.
[0075]
FIG. 18 shows a case where FP compression is not performed in the transfer of the request message from the client side proxy 40 to the server side proxy 30, and FP compression is used in the transfer of the reply message from the server side proxy 30 to the client side proxy 40. This is an example procedure.
[0076]
In the following, the request-source client-side proxy refers to a client-side proxy corresponding to the request-source client, that is, a request message transmission source and a reply message reception destination in processing for a pair of request message and reply message. The client-side proxy.
[0077]
When the server-side proxy 30 receives a request message from a certain client-side proxy (that is, a request-source client-side proxy) 40 among a plurality of client-side proxies (step S1), the server-side proxy 30 serves as a destination server. 20 (step S2). At this time, as processing for the pair of request message and reply message, a state of waiting for reception of the corresponding reply message is entered.
[0078]
Now, when the server-side proxy 30 receives a reply message from the server 20 by the receiving unit 31 (step S3), first, the reply data of the reply message is subject to FP compression by the FP compression determination unit 321. It is checked and determined whether or not (step S4). If it is determined that the reply data is not subject to FP compression (step S4), the received reply message is transferred from the transmission unit 33 to the client side proxy 40 (step S9).
[0079]
If it is determined in step S4 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 S5). Using the fingerprint value as a key, the fingerprint cache 34 corresponding to the requesting client-side proxy 40 is searched (step S6).
[0080]
If the set of the fingerprint value and the corresponding data is registered in the fingerprint cache 34 corresponding to the requesting client-side proxy 40 (step S7), the FP compression processing unit At 323, the received reply message is converted into a format at the time of FP compression using the fingerprint value (for example, FIG. 9B) and transmitted from the transmission unit 33 to the requesting client side proxy 40. (Step S8). At this time, the value of the field (Content-Length: field) indicating the data length in the reply header is set according to the format at the time of FP compression as necessary.
[0081]
On the other hand, as a result of the search in step S6, if the pair of the fingerprint value and the corresponding data is not registered in the fingerprint cache 34 corresponding to the requesting client-side proxy 40 ( Step S7), the following two operations are performed.
(1) In the FP compression processing unit 323, the received reply message is converted into a format for non-FP compression (using the fingerprint value as necessary) (for example, FIG. 9A) and transmitted. The unit 33 transmits the request to the requesting client-side proxy 40 (step S10).
(2) The FP cache management unit 322 associates the fingerprint value with the reply data (using the fingerprint value as a key), and the fingerprint corresponding to the requesting client-side proxy 40 Register in the cache 34 (step S11).
[0082]
Note that either of (1) and (2) may be performed first or in parallel.
[0083]
FIG. 19 shows an example of a processing procedure of the client side proxy 40 from when the client side proxy 40 receives the request message from the client 50 to when the reply message is transferred to the client 50.
[0084]
FIG. 19 describes processing according to a single request from the client 50 of the client side proxy 40. For example, when request messages are simultaneously received from a plurality of clients 50, each request is received. 19 are performed in parallel.
[0085]
FIG. 19 shows a case where FP compression is not performed in the transfer of a request message from the client side proxy 40 to the server side proxy 30, and FP compression is used in the transfer of a reply message from the server side proxy 30 to the client side proxy 40. This is an example procedure.
[0086]
When the client-side proxy 40 receives a request message from the requesting client 50 (step S21), the client-side proxy 40 transmits the request message to the server-side proxy 30 corresponding to the destination server 20 (step S22). At this time, as processing for the pair of request message and reply message, a state of waiting for reception of the corresponding reply message is entered.
[0087]
After that, when the client side proxy 40 receives the reply message from the server side proxy 30 by the receiving unit 41 (step S23), the reply data of the reply message is first subjected to FP compression by the FP compression determination unit 421. It is checked and judged whether it is a thing (step S24). If it is determined that the reply data is not subject to FP compression (step S24), the received reply message is transferred from the transmitter 43 to the client 50 (step S32).
[0088]
If it is determined in step S24 that the reply data of the reply message is for FP compression, the FP compression determination unit 421 further checks and determines whether the reply data is FP compressed (step). S25).
[0089]
If it is determined in step S25 that the reply data of the reply message is FP-compressed (for example, in the case of FIG. 9B), the FP cache management unit 422 determines the fingerprint of the reply data. A value is obtained (step S26), and the fingerprint cache 44 is searched using the fingerprint value as a key (step S27).
[0090]
When the FP decompression processing unit 423 adds data corresponding to the fingerprint value retrieved from the fingerprint cache 44 to the received reply message and uses special information between proxies. After deleting this information, the information is transmitted from the transmission unit 43 to the client 50 (step S28). At this time, if necessary, the value of the field (Content-Length: field) indicating the data length in the reply header is set to the length of the data corresponding to the value of the fingerprint.
[0091]
On the other hand, if it is determined in step S25 that the reply data of the reply message is not FP compressed (for example, in the case of FIG. 9A), the following two operations are performed.
(1) When special information is used between proxies in the FP decompression processing unit 423, the information is deleted from the received reply message and then transmitted from the transmission unit 43 to the client 50 (step S30).
(2) The FP cache management unit 422 obtains the fingerprint value of the reply data (step S29), associates the fingerprint value with the reply data (using the fingerprint value as a key). ) And is registered in the fingerprint cache 44 (step S31).
[0092]
Note that either of (1) and (2) may be performed first or in parallel.
[0093]
By the way, in step S26, the fingerprint is described in the message. However, in step S29, when a fingerprint is described in the message, a method for obtaining the fingerprint from the message, and when no fingerprint is described in the message, a hash function or the like is used based on the reply data. There is a method of calculating a fingerprint value. Even when the fingerprint is described in the message, a method of calculating the fingerprint value based on the reply data is also possible.
Moreover, step S26 / step S29 may be performed between step S24 and step S25, and step S29 may be performed between step S30 and step S31.
[0094]
Further, the determination in step S24 and the determination in step S25 may be performed simultaneously.
[0095]
Next, FIG. 20 shows an operation example in the case where data not registered in the fingerprint cache is transferred from the server side proxy 30 to the client side proxy 40 and the fingerprint cache is registered.
[0096]
(1) Assume that the browser or the like on the client 50 issues a POST method request message to the server 20 with a URL of “/A.cgi”, for example. First, a browser or the like is set so that a request message to the server 20 is sent to the client-side proxy 40.
[0097]
(2), (3) The request message is transferred to the server 20 by the client side proxy 40 and the server side proxy 30 corresponding to the destination server 20.
[0098]
(4) After processing the request message, the server 20 transfers the reply message to the server-side proxy 30.
[0099]
(5), (6) Since the reply data of the received reply message is the first data for the requesting client-side proxy 40, the server-side proxy 30 corresponds to the requesting client-side proxy 40. While registering in the fingerprint cache 34, the reply message is transferred to the client side proxy 40.
[0100]
(7), (8) Since the reply data of the received reply message is the first data, the client side proxy 40 obtains a fingerprint based on the reply data, and stores it in the fingerprint cache 44 together with the reply data. sign up. Then, the reply message is transferred to the requesting client 50 (such as a browser operating on the requesting client).
[0101]
Next, FIG. 21 shows an operation example when the operation shown in FIG. 20 is performed and the cache-registered data is transferred from the server side proxy 30 to the client side proxy 40.
[0102]
(1) to (4) are the same as (1) to (4) in the operation described with reference to FIG.
[0103]
(5), (6) The server side proxy 40 uses the corresponding fingerprint registered in the fingerprint cache 34 corresponding to the requesting client side proxy 40 as the reply data of the reply message received from the server 20. Replace and transfer to the client side proxy 40.
[0104]
(7), (8) The client side proxy 40 detects that the reply data of the reply message has been replaced with the fingerprint, and retrieves the corresponding data from the fingerprint cache 44 using the specified fingerprint. After this is put in the reply body, the reply message is transferred to the requesting client 50 (such as a browser operating on the requester).
[0105]
So far, the description has focused on the reply message transferred from the server-side proxy to the client-side proxy, but of course, the present invention can also be applied to other messages.
[0106]
In the past, when data is transferred from the server-side proxy 30 to the client-side proxy 40, if the data is the same as the data registered in the fingerprint cache, the data is replaced with the data. Although the network traffic is reduced by transferring the corresponding fingerprint, this FP compression may be applied when transferring data such as request data from the client side proxy 40 to the server side proxy 30. Is possible.
[0107]
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.
[0108]
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 that records the program.
[0109]
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.
[0110]
The present invention is not limited to the embodiment described above, and can be implemented with various modifications within the technical scope thereof.
[0111]
【The invention's effect】
  According to the present invention,The server-side proxy provided on the server device side receives the request data issued by the client device to the server device from the client-side proxy provided on the client device side and transfers the request data to the server device. When a device receives reply data that is a reply to the request data addressed to the client device and transfers it to the client side proxy, the received replydataFingerprint generated fromTheIn association with the reply data, a fingerprint cache for each client-side proxy corresponding to the client-side proxy associated with the client device that is the destination of the reply dataRetentionThus, when reply data is received from the server device, the fingerprint is stored in the fingerprint cache for each client-side proxy corresponding to the client-side proxy related to the client device that is the destination of the reply data.RetentionIsingreplyFor data,The replyRespond instead of transferring dataFingerprintBy transferringBetween the server-side proxy and the client-side proxyThe amount of data transferred between them can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a computer network system according to an embodiment of the present invention.
FIG. 2 is a view showing another configuration example of the computer network system according to the embodiment;
FIG. 3 is a view showing still another configuration example of the computer network system according to the embodiment;
FIG. 4 is a diagram showing still another configuration example of the computer network system according to the embodiment;
FIG. 5 is a diagram for explaining a fingerprint used in the embodiment;
FIG. 6 is a diagram for explaining a fingerprint cache used in the embodiment;
FIG. 7 is a view showing an example of a message format used in the embodiment.
FIG. 8 is a view showing another example of the message format used in the embodiment.
FIG. 9 is a view showing still another example of the message format used in the embodiment.
FIG. 10 is a view showing still another example of the message format used in the embodiment.
FIG. 11 is a view showing still another example of the message format used in the embodiment.
FIG. 12 is a diagram showing a configuration example of a server side proxy according to the embodiment;
FIG. 13 is a view showing a configuration example of a client side proxy according to the embodiment;
FIG. 14 is a view for explaining an example of a fingerprint cache in the embodiment;
FIG. 15 is a view for explaining another example of the fingerprint cache in the embodiment;
FIG. 16 is a diagram for explaining still another example of the fingerprint cache in the embodiment;
FIG. 17 is a view for explaining still another example of the fingerprint cache in the embodiment;
FIG. 18 is a flowchart showing a procedure example of a server-side proxy according to the embodiment;
FIG. 19 is a flowchart showing a procedure example of the client side proxy according to the embodiment;
FIG. 20 is a diagram for explaining data transfer between the server-side proxy and the client-side proxy according to the embodiment;
FIG. 21 is a view for explaining data transfer between the server-side proxy and the client-side proxy according to the embodiment;
FIG. 22 is a diagram for explaining a conventional computer network system;
[Explanation of symbols]
2 ... ASP server center
4. User office
12 ... ASP server center LAN
14 ... WAN
16 ... LAN in user office
20 ... Server device
30 ... Server-side proxy device
40 ... Client-side proxy device
50. Client device
31, 41 ... receiving unit
32, 42 ... processing section
33, 43 ... Transmitter
34, 44 ... Fingerprint cash
35, 45 ... URL / FP table
321, 421 ... FP compression determination unit
322, 422 ... Fingerprint cache management unit
323... FP compression processing unit
423 ... FP decompression processing part
324, 424 ... URL cache processing unit
325,425 ... FP decompression / decompression processor

Claims (7)

Reply data transmitted from the client device to the server device, received as request data relayed to the client-side proxy, transferred to the server device, and sent as a reply to the request data from the server device to the client device the a server side proxy data transfer method for transferring to the client-side proxy,
Each of reply data that is a response to each of request data transferred from each of a plurality of client side proxies is received from the server device,
Generating a fingerprint for each of the reply data;
Each of the generated fingerprints is associated with each of the original reply data, and each client-side proxy that communicates with each client device that is the destination of the reply data is used as a fingerprint cache for each client-side proxy. Hold and
Receiving reply data from the server device that is a reply to the request data transferred from the client-side proxy;
Generating a fingerprint that is a fingerprint of the reply data;
Determining whether the fingerprint is held in a fingerprint cache for each client-side proxy corresponding to a client-side proxy that communicates with a client device that is the destination of the reply data;
If it is determined in the determination that the certain fingerprint is held in the fingerprint cache for each client-side proxy corresponding to the certain client-side proxy, the certain fingerprint is used instead of the certain reply data. Send to the client-side proxy as addressed to the client device,
If it is determined in the determination that the fingerprint is not stored in the fingerprint cache for each client-side proxy corresponding to the client-side proxy, the fingerprint is associated with the reply data. A data transfer method comprising: adding to the fingerprint cache for each client-side proxy corresponding to the client-side proxy and transmitting the reply data to the client-side proxy as addressed to the client device. The server apparatus receives a plurality of request data transmitted from each of the plurality of client apparatuses to the server apparatus and relayed to each of the client side proxies in charge of access to the server apparatuses of the plurality of client apparatuses. And the reply data transmitted from the server device to each of the client devices as a response to each of the plurality of request data is forwarded to each of the client side proxies acting as a proxy of the client device that is the destination of the reply data. A server-side proxy that
Reply data that is a response to request data transferred from each of a plurality of client-side proxies is received from the server device, and is further transferred from a client-side proxy of the plurality of client-side proxies. Receiving means for receiving reply data that is a reply to the request data;
Fingerprint generation means for generating a fingerprint of each of the reply data, and further generating a fingerprint that is a fingerprint of the reply data;
Each of the generated fingerprints is associated with each of the original reply data, and for each client-side proxy acting as a proxy for each client device that is the destination of the reply data, a client-side proxy fingerprint cache Holding means for holding as,
Determining means for determining whether or not the fingerprint is held in a fingerprint cache for each client-side proxy corresponding to a client-side proxy that is a proxy for a client device that is the destination of the reply data;
When the determination unit determines that the fingerprint is held in a fingerprint cache for each client-side proxy corresponding to the client-side proxy, the fingerprint is replaced with the one or more instead of the reply data. When the determination means determines that the fingerprint is not held in the fingerprint cache for each client-side proxy corresponding to the client-side proxy, A fingerprint and the reply data are associated with each other and added to the client-side proxy fingerprint cache corresponding to the client-side proxy, and the reply data is added to the client Server side proxy, characterized in that it comprises a transmitting means for transmitting said to certain client-side proxy as 置宛.   The server-side proxy according to claim 2, wherein the fingerprint is a value obtained by compressing the reply data by a predetermined method.   The server-side proxy according to claim 2, wherein the fingerprint is a value obtained by applying a predetermined hash function to the reply data.   The client-side proxy is connected to the client device via a first local area network, and the server-side proxy is connected to the server device via a second local area network. The server-side proxy according to claim 2, wherein there is a server-side proxy.   The server-side proxy according to claim 2, wherein the client-side proxy and the server-side proxy are connected via the Internet. The server apparatus receives a plurality of request data transmitted from each of the plurality of client apparatuses to the server apparatus and relayed to each of the client side proxies in charge of access to the server apparatuses of the plurality of client apparatuses. And the reply data transmitted from the server device to each of the client devices as a response to each of the plurality of request data is forwarded to each of the client side proxies acting as a proxy of the client device that is the destination of the reply data. A program for causing a computer to function as a server-side proxy
Reply data that is a response to request data transferred from each of a plurality of client-side proxies is received from the server device, and is further transferred from a client-side proxy of the plurality of client-side proxies. A receiving function that also receives reply data that is a reply to request data;
A fingerprint generation function for generating a fingerprint of each of the reply data, and further generating a fingerprint that is a fingerprint of the certain reply data;
Each of the generated fingerprints is associated with each of the original reply data, and for each client-side proxy acting as a proxy for each client device that is the destination of the reply data, a client-side proxy fingerprint cache Holding function to hold as,
A determination function for determining whether or not the fingerprint is held in a fingerprint cache for each client-side proxy corresponding to a client-side proxy that is a proxy of a client device that is the destination of the reply data;
When the determination function determines that the certain fingerprint is held in the fingerprint cache for each client-side proxy corresponding to the certain client-side proxy, the certain fingerprint is used instead of the certain reply data. When the determination function determines that the fingerprint is not held in the fingerprint cache for each client-side proxy corresponding to the client-side proxy, A fingerprint and the reply data are associated with each other and added to the client-side proxy fingerprint cache corresponding to the client-side proxy, and the reply data is added to the client Program for realizing the transmission function to the computer to the transmission to the certain client-side proxy as 置宛.

Images