MXPA00001233A - A distributed system and method for prefetching objects - Google Patents

Abstract

In an internet access system which includes asatellite link, a distributed proxy server (68) is provided which reduces a delay associated with the retrieval of inline objects of web pages. The distributed proxy server (68) includes an access point component (70) and a satellite gateway component (72). The access point component (70) runs on the client (browser) side of the satellite link and communicates with web browsers (20A-20N). The satellite gateway component (72) runs on the internet side of the satellite link and communicates with web servers (26). As a web page is retrieved over the satellite link, the satellite gateway component (72) parses the base file component of the web page to identify any references to inline objects of the web page, and prefetches each such inline object. The distributed proxy server thereby eliminates the delays normally associated with (a) waiting for the web browser (20) to receive the base component and request the object(s), and (b) waiting for the browser's object request(s) to be transmitted over the satellite link. The prefetched objects are transmitted over the satellite link to the access point component (70), which in-turn stores the prefetched objects in an object cache (71). When a web browser (20) requests an inline object, the access point component (70) checks the cache (71), and if the object resides therein, returns the object to the browser (20) without forwarding the object request over the satellite link. Traffic over the forward satellite link is thus reduced. The method implemented by the distributed proxy server (68) can also be used to reduce delays and traffic over other types of links, including non-wireless links.

Description

A DISTRIBUTED SYSTEM AND METHOD FOR PREVIOUSLY LOOKING FOR OBJECTS BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates, generally, to the transfer of data. More specifically, the invention relates to the transfer of digital data over a digital network.

II. Description of the Related Technique The flourishing of the Internet (interconnected networks) has stimulated many companies and individuals to establish their presence in it. For example, a company can create a web page in which it describes its products and services, to allow a user to place a purchase order. These network pages are stored on network servers. A user can access a network page from the network server, using the software (program) for quick review of the network that operates on a computer. The network page may contain links to other information on the same site or on other network sites.

Figure 1 is a block diagram showing an Internet connection. A user originates a file request from a light network revision 20. This network revision 20 may comprise a personal computer, a network terminal or any other terminal mode of the digital user capable of running the network quick review software. The request is passed through a series of itineraries 22A-22N of the Internet 24. These itineraries 22A-22 do not examine the contents of the request, but simply transfer the request to an appropriate network server 26, according to a header. of direction. The network server 26 examines the contents of the request and responds with the required file. When a user wants information from; Access on the Internet, this user enters a uniform source locator (URL) in the network fast browser. This URL is basically an indicator of the location of an object. For example "http: \\ www internic.net \ rfc \ rfcl738.txt" is the URL address that points to a Request for Comments document, which describes the uniform source locators. In the URL, the "http" indicates the Hiper Transfer Text Protocol (HTTP), the protocol used to access the site. The double diagonal indicates that the name of the guest follows, such as "www.internic.net". A simple diagonal indicates that it follows a directory or file name. In this case, "rfc" is a directory and "rfcl738.txt" is a file in that directory, which is displayed when this URL is requested by the fast network browser 20. 5 The World Wide Red is formed at the top of •? Te_net. HTTP is the most commonly used client / server protocol on the World Wide Network. HTTP is used to establish communication between a client and a server and pass the commands and files between the two systems. HTTP provides a means for a fast network browser to access the network server and request documents created using the HyperText Composition Language (HTML). The HTML network page can include images, sound clips, text files and other types of objects. Some of the objects may not be part of the original main HTML file (the base component of the Network document), requested by the network fast browser 20. Instead, the main HTML file contains external references to these objects online, which are in the form of other data files on the server. When a user retrieves the main HTML file in the network fast browser, the online objects are also recovered and inserted into the document's display. 25 Thus, the HTML document (or "page" '1 really consists of ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ j ^^^^ f ^^ j ^^^^^^^^^^ Jg ^ jgjyjg ^ yíj ^^^^^^ 1_¿_g _____ J_ ^ of the main HTML file along with any additional online sound, graphics and multimedia objects, specified with the main file. For example, online objects may include ad headers, 5 slides, ad lists, graphic images, sound clips or other such products. Figure 2 is a time diagram showing the transfer of data to and from the network fast browser 20. In Figure 2, time progresses from left to right. The arrows pointing "1" upward indicate output messages from the network rapid examiner 2J, attempted for the network server 26. The down arrows indicate incoming messages received in the network fast browser 20 from the server 26 of the network. network 15 For simplicity of illustration, every incoming and outgoing message seems to be transferred instantaneously In current computers, the transfer of each message typically requires a noticeable amount of time. initial. In response, an input message 32 carries the first portion of a response to the request carried in the output message 30. An input message 34 and an input message 36 correspond to a second and third portion of the response.

Assuming that the input message 32 contains an external reference to an online object. The network rapid examiner o20 examines the input information and in response sends an output message 38, which carries a request for the object in line. For purposes of illustration, suppose that the line 3n object is a sound clip. Following the exit message 38, the network fast browser 20 receives an input message 40, which contains additional information corresponding to the initial request carried in the output message 30. After receipt of the input messages, corresponding to the initial request, the fast network browser 20 begins to receive the sound clip within the input message 42. In an input screen 44, the fast network scanner 20 continues to receive information concerning the sound clip. Suppose that the input message 42 contains an external reference to an object m line, which is an ad header. An exit message 46 carries a request for this announcement header. Following the exit message 46, the network fast browser 20 receives an input message 48 and an input message 50, which contains additional information which corresponds to the sound clip Finally, in an input message 52, the ^ .. ^ ,. .. ^^. ^. ^ Btt ,. - ^ ¡- 1- -r? ? mr .- ^ ~ s ^ ~ - fast network browser 20 receives the information concerning the ad header. Each time the fast network browser 20 requires information from the network server 26, a delay is incurred. For example, note that a time delay? T1A occurs between the output message 30 and the corresponding input message 32. This delay includes two primary components: (i) the round trip delay associated with the connection to the network server 26 and (ii) the response time of the network server 26. In the example of Figure 2, the transfers of the on-line objects are delayed by the transfers of the previously requested objects and the delays of the main and time file? T2A and? T3A are, therefore, greater than the delay? T1A As described in more detail below, because the HTTP protocol requires the network fast browser to examine the main file and generate separate requests for objects online, the introduction of a link that introduces a dignifying delay can greatly increase the amount of time required to fully recover and display a network page. For example, if the user's Internet access channel includes a satellite link, the time required to retrieve a network page that includes a single online object will be at least twice the round trip delay of the link. satelite. In addition, the need to separately request objects online results in unnecessary traffic on the communication link. The present invention is directed to overcome these problems, without the need to modify the HTTP protocol.

COMPENDIUM OF THE INVENTION The present invention is directed to solve the above problems, by the provision of a distributed system and a method to pre-search the online objects of documents. In a preferred embodiment, the system is in the form of a distributed proxy server for use in an Internet access system, which includes a satellite link. The distributed substitute server includes a component of the access point which goes on the client's side (fast examiner) of the satellite link and communicates with the network fast examiners and includes a satellite gate component, which is on the side from the Internet (network server) of the satellite link and communicates with the network servers. In operation, when a network server returns to a main file of the network page that has been requested by the user, the satellite gate component ana- loises the main file to identify any reference in the objects online, and Fsfito «fa search these objects ar.sdt.1 previously the network server. The objects are thus requested without waiting for the rapid examiner to receive the main file and generate requests for the objects online. The satellite gate sends forward the previously searched objects on the satellite link to the access point component, which, in turn, stores the objects in line until requested by the rapid examiner. If the access point component receives a request for an object, the c'A 'eside in the cache memory, the access point component returns the object without allowing the object request to be transmitted over the satellite link. The distributed proxy server thus reduces the delay associated with online object requests and reduces traffic on the satellite link. Although the system, in the preferred mode, operates in conjunction with a satellite link, the underlying method and architecture can also be used to increase performance over other types of links, including wireless links. preferred mode operates in the system using HTTP, the invention can also be used with other types of document retrieval protocols, in which ^ HÜÜHMI online objects are requested separately from the base component. According to the invention, it is provided in a customer-server type document retrieval system, in which the online objects of the documents are requested and retrieved separately from the base components of the documents, a distributed system for reduce the degradation of performance caused by a communication link. The distributed system comprises a first component that goes on the side of the client of the communications link and communicates with the clients, the first component is adapted to receive requests for documents from the clients and send forward the requests on the communications link for the jr. I stop. The system also includes a second component, which is on the side of the communication link server and communicates with the document servers, this second component is adapted to receive requests for documents from the first component on the communication link and send forward the requests to the document servers, these requests cause the document servers to return to the base components of the requested documents. In operation, the second component processes the base components returned by the document servers by at least (i) analyzing the base components for identify references in online objects, (ii) pre-search the online objects, and (ni) forward the base components and the previously searched objects previously searched for the first component. This first component stores the received online objects previously searched for the second component in a cache, and responds to object requests from the clients by forwarding the objects online to the clients from the cache.

BRIEF DESCRIPTION OF THE DRAWINGS The characteristics, objects and advantages of the invention will become apparent from the detailed description that follows, when taken in conjunction with the drawings, where similar parts are identified with similar reference numbers through the description and wherein: Figure 1 is a block diagram showing an Internet connection; Figure 2 is a time diagram showing the transfer of data to and from a fast network browser; Figure 3 is a block diagram showing an Internet connection, comprising a satellite link; Figure 4 is a time diagram illustrating the transmission of the data shown in Figure 2, after the introduction of a satellite link into the system; Figure 5 is a block diagram, showing an Internet connection comprising a substitute server; Figure 6 is a block diagram showing a digital data network, comprising a distributed substitute server, according to the invention; Figure 7 is a data flow diagram, showing a mode of data transfer, according to the invention; and Figure 8 is a time diagram illustrating the transmission of the data shown in Figures 2 and 4, and transferred over the distributed proxy server, according to the invention.

DETAILED DESCRIPTION OF A PREFERRED MODALITY The use of wireless communication systems for the transmission of digital data has become more and more pervasive. In wireless systems, the most precious resource in terms of cost and availability is typically the wireless link itself. Therefore, a main design goal in a communications system comprises a wireless link for the efficient use of the available capacity of the wireless link. In addition, typically, the delay associated with the path of the wireless link is significantly larger than the delay associated with the rest of the network. Therefore, it is also convenient to reduce this delay associated with the use of a wireless link. Although autonomous computers are very powerful tools, they become even more powerful when cou together to form a network. As an increasing number of computers are cou together, increasing demands are placed on the network, the cuaj.es are cou together. If computers are placed one wax away from another, they can be interconnected by dedicated wireline connections. A computer which is located at a significant distance away from a network, can access this network through the connection through a standard telephone line. However, telephone lines have limited bandwidth, which places a limit on the rate at which data can be transferred between the computer and the network. Therefore, alternative resources for access to digital data networks have been developed. For exam satellite links can be used to transfer digital data within a data network. The use of a geosynchronous satellite link introduces a round trip delay approximately equal to half a second. The protocols currently in use in typical digital data networks, were not developed with such large round trip delays in mind. The use of a link, which introduces a significant delay, may decrease the average data transfer rate nci below an acceptable level. The present invention reduces the inefficiencies caused by using a link which introduces a significant delay for access to a digital data system. The present invention also increases the efficient use of the link of the digital data system. Figure 3 is a block diagram illustrating an Internet connection, comprising a satellite link. In Figure 3, the fast browser 20 of the network is cou to a satellite terminal 60. This satellite terminal 60 is cou to a station 64 on the ground, by means of a geosynchronous satellite 62. Station 64 on the ground is cou to the series of guides 22A-2N of the Internet 24. This Internet 24 is cou to the server 26. of network. The inclusion of the geosynchronous satellite link introduces a delay of approximately 270 milliseconds by transmitting a signal between the satellite terminal 60 and the station 64 on the ground. Thus, each data transfer between the fast browser 20 of the network and the server 26 of the network exhibits a round trip delay of at least half a second. Figure 4 is a time diagram illustrating the transmission of the data, shown in Figure 2, on a system comprising a satellite link. Due to the nature of the requirements included for online objects, not only does the system incur a delay of the initial system equal to the round trip delay, but it also incurs an additional delay as subsequent requirements are obtained for the objects in line. A message that enters 30 '.. takes the initial URL request, which is sent forward on the wireless link. Due to the delay of the round trip of the link, a message 32 'entering, which carries the first portion of a response to the request carried in the output message 30' is received after a time delay? T1B Suppose that a message 32 'of input, comprises an external reference to the object in line, which is a sound clip. In response, the fast browser 20 of the network sends an outgoing message 38 ', the cu1 carrying a request for the on-line object. Because the round trip delay of the link, an input message 42 ', which carries the first portion of a response of the request carried in the output message 38' is received after a delay of the time delay? T2B . Suppose that a ^ _ ^ _ s ™ gjA_ sensitive message 42 'contains an external reference to an online object, which is an ad header. An exit message 46 'carries a request for this advertisement header. Due to the round trip delay of the link, an input message 52 ', which carries the first portion of a response to the request carried in the output message 46' is received after a delay of the time delay? T3B.

Note that the delays in time,? T1B,? T2B and ? T3B are significantly greater in Figure 4 than the time delays? T1A,? T2A and? T3A in Figure 2. This difference is mainly due to the round trip delay associated with the wireless link. Each time a request is made, the first response is delayed by at least the round trip delay. ' Thus, the inclusion of a link, which introduces a relatively long delay, can significantly decrease the average data transfer rate, just as it introduces a significant initial fixed delay. Figure 5 is a block diagram showing an Internet connection comprising a substitute server 66. This substitute 66 server is designed for the interface of a plurality of fast 20A-20N network browsers on the Internet 24. Substitute 66 server can XJ6 be designed to protect fast 20A-20N network browsers (and the network on which they operate) from hostile invasion through the Internet 24. For example, proxy server 66 can be a one-way server, which blocks to other Internet users access to the internal network. Only packets that are received in response to a request from the internal user are allowed again through the substitute server 66 from the Internet 24. Other coughs received at the substitute server 66 are not passed to the 20A-20N Rapid Examiners in the network. Because the substitute server 66 provides a single connection point for a user set, it is very easy to perform functions such as virus scanning, filtering contents and controlling access to the proxy server 66 rather than the 20A fast examiners. -20N individual network Thus, a company can retain control over its internal network more easily using the substitute server 66 as a central control point for the network. The substitute server 66 is designed to be transparent to the users of the system, which means that the fast 20A-20N network examiners are not aware of the existence of the substitute 66 server. Although the network 20A-20N fast examiners can not being aware of the substitute server 66, the end result is that these 20A-20N fast browsers on the network will receive a combination of information from the substitute server 66 and the Internet 24. Many times, the save is used to increase system performance as perceived by the fast 20 band examiner. The term "saved" refers to the process of storing copies of the document received by the substitute server 66 on a local storage medium. (typically a disk, but it can also be the main memory for the saved for a short period). Because the substitute server 66 provides a central location, where each fast network scanner 20A-210N has access to the Internet 24, the substitute server 66 can frequently store the access documents, so they are easily available to other fast 20 band examiners who request them. For example, in a financial services organization, many different fast examiners can access the Wall Street Journal homepage on any given day. If the substitute server 66 has the ability to save, the Wall Street Journal home page can be saved after the first request of each day. Subsequent requests receive the home page of the Wall Street Journal magazine from local memory rather than Internet 24. In general, saving improves system performance, reducing latency and saving network bandwidth. A saved class, called "Prerequisite", involves saving documents that are likely to be requested by a customer. An example of a document that is likely to be required by a client is an online object, within the main file previously requested. If the substitute server originally analyzed the main file, this substitute server can determine that the document contains an external reference to an online object and can begin the retrieval of the object online before the actual request arrives from the network fast browser. In the case of online objects previously searched, the prediction of the request is highly deterministic. In the rare case where the Fast Band Browser software is not configured to load on-line objects automatically, the prediction will fail. Likewise, if the user interrupts the recovery before all online objects are required, some of these objects will not be required by the fast network browser. However, in the general case, each of the online objects referred by the main document will be requested by the fast network browser. $ 1 If one tries to integrate a substitute server of the prior art, which comprises an ability to save on an Internet connection comprising a wireless satellite link, the performance of the system is not greatly improved. For example, reference is again made to Figure 3, assuming that a substitute server is inserted between the ground station 64 and the guide element 22A. When an initial request is generated by the network fast scanner 20, it is sent forward from the satellite terminal 60 over the wireless link to the ground station 64. This ground station 64 sends forward the request of the substitute server, which, in turn, sends forward to the Internet 24. When the response of the Internet 24 is received, the substitute server sends it forward to station 64 on the ground. The substitute server also analyzes the information in the response to the initial request to determine the presence of objects online. This substitute server sends substitute requests for the objects online and stores these objects as they arrive. In the meantime, the response to the initial request is sent forward over the wireless link to the network fast browser 20. When this fast network browser 20 receives the response, it sends forward a request for the online object, again over the wireless link. When the substitute server receives the request, it responds with the previously saved searched information, thus eliminating any extra delay associated with the transmission over the Internet 24. The information corresponding to the on-line object crosses the wireless link to the fast browser 20 of the network. Thus the round trip delay of the wireless link is not avoided. Because this delay of the round trip over the wireless link is the most significant factor in determining the latency of the system in Figure 3, the performance of the system is not significantly improved by the inclusion of a substitute server on the side of the gate. satellite link. Similarly, assuming that the substitute server of the prior art is inserted between the terminal 60 of the satellite and the rapid examiner 20 of the network. When an initial request is generated by the rapid browser 20 of the network, it is sent ahead to the substitute server, which sends it forward to the terminal 60 of the satellite. Terminal 60 of the satellite sends it forward over the wireless link to station 64 on the ground. This station 64 on the ground sends the request to the Internet 24. When the response is received from the Internet 24, station 64 on the ground sends forward the response on the wireless link to terminal 60 of the satellite and the substitute server. This substitute server sends forward the response of the rapid browser 20 of the network. This substitute server also analyzes the information to determine the presence of objects online. The substitute server pre-checks the objects online, sending a substitute request for them over the wireless link. When the fast web browser 20 receives the initial response, it sends forward a request for the online object to the substitute server. When this substitute server receives the request from the fast scanner 20 of the network, it intercepts the request and does not send it forward over the wireless link. This substitute server waits for the substitute request and the corresponding response to cross the wireless link and send forward the fast web browser information, when available, thus eliminating any extra delay associated with the transmission of the initial response from the proxy server to the network fast scanner 20, and transmitting the request from the fast scanner 20 of the network. network to a substitute server. However, the round trip delay of the wireless link is not avoided. Because this round trip delay over the wireless link is the most significant factor in determining the system latency in Figure 3, the performance of the system is not significantly improved by the "* -. A ** t¿ inclusion of the substitute server on the side of the satellite terminal of the satellite link. Figure 6 is a block diagram showing the digital data network, comprising a distributed substitute server, according to the invention. In Figure 6, the network 20A-20N fast browsers are coupled to the Internet 24 by means of a distributed substitute server 68. This distributed substitute server 68 comprises two components: an access point component 70 ("access point"). access ") and a satellite gate component 72 (" satellite gate "). The access point 70 and the satellite gate 72 can be incorporated into one or more work stations or personal computers, which operate corresponding software components. Some or all of the functions of the access point 70 and the satellite gate 72 may alternatively be performed using a specific application hardware (computer equipment). This access point 70 and the satellite gate 72 are connected via a wireless link on the satellite 62. The network rapid browsers 20A-20N are preferably connected to the access point 70 by a local area network (not shown) . As illustrated in Figure 6, the access point 70 carries a cache 71 of objects for temporarily storing the objects that have been previously searched by the satellite gate 72. The distributed substitute server 68 facilitates the efficient transfer of data by reducing the effect of the round trip delay associated with the crossing of the satellite link. The access point 70 and the satellite gate 72 can also provide services, typically performed by the substitute servers of the prior art. In the preferred embodiment, the use of the distributed substitute server 68 is transparent to the entities coupled to the Internet 24, such as the network server 26 and the network fast browser 20. Figure 7 is a data flow diagram showing a mode of data transfer, according to the invention, in which the required network page is comprised of a main file component, which refers to an object online. In block 80, the fast network browser 20 requires a network page. The access point 70 receives the request and sends it forward to the satellite gate 72 on the wireless link in the block 82. After some delay, the request is received in the satellite gate 72. In block 84, the satellite compuertet 72 forwards the request to the Internet 24. This gate of ~ * l f ^. S-satellite 72 may comprise a network communication module to execute this function. The network server 26 receives the request and responds with the main file. The satellite gate 72 receives the main file from the Internet 24 and forwards it to the access point 70 in the block 86. After the file crosses the wireless link, the access point 70 forwards the master file to the fast examiner. of network in block 88. In block 90, the network fast browser 20 receives the main file. Before, during or after the transfer transmission of block 86, the satellite gateway analyzes the main file, extracts an external reference to an on-line object and sends a substitute request for the online object over the Internet 24 in block 92. For example, the satellite gate 72 may comprise an analysis module and a substitute request generation module for carrying out these functions. Likewise, in block 92, the satellite gate 72 sends a message to the access point 70 that identifies the online object which was previously searched. For example, the satellite gate 72 may comprise a message module which creates and sends messages to the access point 70. In block 94, the access point 70 receives the message fc * T objects previously searched and stored for later reference, such as within a cache module. In block 96, the network fast browser 20 sends forward a request for the online object. In block 98, access point 70 compares the request to the list of previously searched objects. If the request corresponds to an entry in the list of previously searched objects, this request is intercepted and is now sent forward over the wireless link. If the requested object does not correspond to an entry in the list and is not available in the cache, the access point 70 forwards the request on the wireless link. This function can be carried out by the analysis of the message and the comparison module. In the example of Figure 7, because the online object appears in the list of objects that have been searched or are currently being searched, the access point 70 intercepts the request and does not forward the request over the link. satelite. Meanwhile, in block 100, the on-line object is received at satellite gate 72 and is automatically sent forward to access point 70. Note that satellite gate 72 has not received a request for the object online and is sent a response to the initial request to access point 70, which contains the information that the point of Y. l3éi + 1 access 70 has not requested from satellite gate 72. Such response is named a "chubby response". For example, the satellite gate 72 may comprise a plumb response module, which performs these functions. In block 102, the access point 70 receives the object and sends it forward to the network fast browser 20. In block 104, the fast network browser 20 receives the object inline. In this way, the delay associated with waiting for the transmission that the request on the satellite link is avoided and the online objects are transferred briefly after the main file. In addition, the bandwidth normally occupied by wireless responses for online objects is released for other uses. The efficiencies gained using the data flow as described in Figure 7, can be easily viewed with reference to the time diagram of Figure 8. This Figure 8 is a time diagram illustrating the transmission of the data shown in the Figures 2 and 4, as transferred on the distributed substitute server, according to the invention. In order to illustrate the flow of data more clearly, in addition to the data flow as perceived in the network fast browser 20, Figure 8 also shows the data flow as perceived by the access point 70 and by the gate Satellite 72. An exit message 130 from the network fast browser takes the initial URL request. The access pin 70 sends forward a corresponding output message 130 'on the wireless link. The satellite gate 72 sends a corresponding output message 130"over the Internet 24. Note the delay between the output message 130 'and the output message 130" due to the introduction of the wireless link. An input message 132"carries the first portion of a response to the request of the output message 130". An entry message 134"and another message entry 136" carry a second and third portion of the response. The input message 132"carries an external reference to an on-line object, which is supposed to be a sound clip, the satellite gate 72 analyzes the input message 132" and recognizes the external references. In an output message 138", the satellite gate 72 sends a substitute request on the Internet 24 for the sound clip, in this way it pre-looks for the sound clip The input messages 132", 134"and 136" are sent forward to access point 70, where they are received as input messages 132 ', 134 'and 136', respectively, once again incurring a delay due to the wireless link. The access point 70 sends forward them to the network fast browser 20, where they are received as the input messages 132, 134 and 136, respectively. In response to the input message 132, the network fast browser 20 sends an output message 138 requesting the sound clip. Note that at the moment that the exit message 138 is sent from the network fast browser 20, this exit message 138"has already been sent forward by the satellite gate 72 to the Internet 24. Therefore, the access 70 intercepts the request and does not send it forward to gate 72, thus reducing the amount of data sent over the satellite link.Therefore, in Figure 8, no corresponding output message 138 'is sent forward from the point access 70 to the satellite gate 72. In this satellite gate 72, an input message 140"is received as the fourth and last response to the original request and is sent forward to the access point o70, where it is received as the input message 140 '. An input message 142"and another input message 144" are received in response to the request for the sound clip. The input message 42"carries an external reference to an on-line object, which is supposed to be an advertisement header Once again again, the satellite gate 72 analyzes the input message 142" and detects the external reference to the ad header. An exit message 146"is sent by the satellite gate 72 carrying a substitute request for the ad header In the meantime, the entry messages 142" and 144"are sent automatically to the access point 70 without waiting for a corresponding request. In this way, the online objects are both previously searched and transferred previously over the wireless link, thus significantly reducing the latency perceived by the network fast browser 20. , 142"and 144", are received as input messages 142"and 144", respectively, in the access point 70. The input messages, 142"and 144", are sent forward to the network fast scanner 20 after which have been requested by the network fast browser 20 in the output message 138. They are received by the network fast browser 20 as input messages 142 and 144, respectively. it is upon receipt of the input message 142 which contains the external reference to the advertisement header, the network fast browser 20 sends an outbound message 146 which requires this announcement header. Once again, the access point 70 intercepts the request and no corresponding output message 146 'is sent forward from the access point 70 to the satellite gate 72. In the meantime, the satellite gate 72 continues to receive a message from input 148"and another input message 150" in response to the request for the sound clip and sends them forward to the access point 70. This access point 70 receives them as the input messages 148 'and 150' subject to the delay introduced by the wireless link. The access point 70 sends these transmissions forward to the network fast scanner 20, when they are not received as the input messages, 148 and 150. In response to the request in the output message 146"for the announcement header, a input message 152"is received at satellite gate 72 and is automatically sent to access point 70, without waiting for a corresponding request. This access point 70 receives the advertisement header information as an input message 152 'and sends it forward to the network fast browser 20 in response to a request carried in the outbound message 146, where it is received as an incoming message 152. The examination of Figure 8, compared to the prior art of Figure 4, reveals the efficiencies introduced by the use of the present invention. Notice that there is a substantial delay? T1C enter the input message mfi * ^ 3 -i 130 and the other input message 132 in Figure 8, just as there is a substantial delay? T1A between the input message 30 'and the other input message 32' in the Set 4. A large portion of this delay is due to the Round trip delay associated with the use of the wireless link. However, it should be noted that the substantial delay? T2B between the output message 39 'and the input message 42' of FIG. 4, is not displayed by the delay? T2C, between the output message 138 and the message entry 142 in Figure 8, due to the fact that the information was previously searched and also previously transferred in a chubby response. In addition, the substantial delay? T3B between the output message 46 'and the input message 52' of FIG. 4, is not exhibited by the delay? T3C between the output message 146 and the input message 152 of FIG. , for the same reason. The delays? T2C and? T3C in the Figure 8 are comparable to the delays? T2A? T3A in Figure 2. In this way, the average data rate is increased by the use of the invention and the lat ging associated with the use of the system is decreased. In Figure 7, the access point 70 has been notified that the online object has been previously searched in block 94, before the online object request is made by the rapid browser 20 of the network in the block 96. However, in some cases, the network fast browser 20 may request the object online before receiving the previous search notification. In such a case, the access point 70 may store the request for some pre-programmed time period, such as three seconds. If, within the period of time, the object does not appear in a list of previously searched objects, nor is the object received in the access point 70, this access point 70 can forward the request to the satellite gate 72. By delaying the transmission of the request, the number of requests transmitted over the wireless link can be reduced. In an alternative embodiment, these problems of correlating requests from the network fast browser 20 with the objects that are in the process of being previously searched and sent forward in a chubby response can be avoided. In one embodiment, the access point 70 analyzes the input files to determine the presence of inline objects in a similar manner as the satellite gate 72. The access point 70 assumes that the satellite gate 72 will pre-screen all of these objects online. For example, when the main file is received in block 88 at access point 70, this access point 70 can analyze the main file to extract any external reference to online objects.

The access point 70 can assume that the gate 72 is in the process of previously searching the objects in line and can create its own list of previously searched objects, which comprises all the objects in line. Because the access point 70 already receives the main file before the network fast browser 20, the access point 70 can establish its list of previously searched objects before any request is received from the network fast browser 20. If a request is received in the list of previously searched objects, but the object itself is not received at the access point 70, within a given period of time, this access point 70 can send the request to the gate Satellite 72. Note that in this embodiment, the transfer of the notification data from the satellite gate 72 to the access point 70, noted in block 92 of Figure 7, does not occur, reducing the amount of data transferred over the satellite link. Because the correlation problem is avoided, the access point 70 does not need to request the delay for the objects to receive the request for an object, which is neither available nor in the list, thus decreasing the general latency associated with the use of the system. In yet another alternative embodiment, the correlation problem is solved without increasing the functionality of the access point 70 to include the analysis. Referring again to Figure 7, when the satellite gate 72 receives the main file of the Internet 24 in block 86, it can first analyze the main file to determine if there is any external reference to the objects online, before sending forward the information from the main file to the access point 70. If there are no external references, the satellite gate 72 can immediately forward the main file to the access point 70. If one or more external references are obtained, the satellite gate 72 You can request and receive data that corresponds to one or more of the objects online, before starting the transfer of the main file to the access point 70. In this way, the online objects follow consistently directly after the main file and thus , access point 70 is available, when requested by the network rapid scanner 20. In one embodiment, the satellite gate 72 receives all the objects online before starting the transmission of the main file to the access point 70. In another embodiment, the satellite gate 72 receives one or more of the objects in line, before starting the transmission of the main file to the access point 70. In yet another embodiment, the satellite gate 72 receives a predetermined amount of data which may correspond to a portion of one or more of the objects online, before starting the transmission of the main file to the access point 70. In addition to avoiding the correlation problem, this method does not require that the notification messages be sent from the satellite gate 72 to the point of access 70, thus reducing the flow of traffic over the wireless link. Because the correlation problem is avoided, access point 70 does not need to delay forwarding requests for objects that require a request for an object which is not available, thus decreasing the overall latency associated with the use of the system. The immediate availability of the online objects of the network fast browser 20, after displaying the main network page in each of these modes, has the advantage of providing the appearance of the instantaneous response to the human user. In yet another embodiment, upon receiving a main file in the satellite gate 72, this satellite gateway 72 analyzes the main file and begins to request the objects online. As the online objects are received, the satellite gate 72 forward these objects in line to the access point 70. After the satellite gate 72 has been requested, received and transferred, all or a portion of the objects in line, that include nested online objects inside ~ »G ..

A * of other objects in line, the satellite gate 72 starts sending the main file forward to the access point 70. The transfer of the previously searched inline objects, before the main file is transferred, ensures that all the objects in line are available to access point 70 before that? are requested by the rapid network examiner 20. Furthermore, this method does not require the use of notification messages or the inclusion of additional functionality in the access point 70 and allows this access point 70 to send requests for unknown objects without the insertion of the intentional delay. As noted above, the data is typically transferred over the current standard digital data networks, typically according to the HTTP protocol. This HTTP is a request / response protocol. The client sends a request to the server and this server answers with a response. This simple protocol avoids the use of multi-stage indication routines at the start of each data transmission. However, there is no provision in the HTTP protocol for a client to receive an unsolicited data transfer in a broad response message. In the preferred embodiment, the link connecting the satellite gate 72 to the access point 70 comprises . ~ *:? "* í an element for transferring unsolicited data, using a wide response message.To provide such functionality, the link connecting the satellite gateway 72 to the access point 70 is outside the pure HTTP protocol. It is important that the distributed proxy server be transparent to the network fast browser 20 and the network server 26 For this reason, it is important that the distributed proxy server 68 support well-known data transfer protocols, such as HTTP, at least as perceived by external entities However, because the satellite gate 2 and the access point 70 are similar units controlled by a common access provider, it is not necessary that the link connecting the access point 70 and the gate Satellite 72 operate in accordance with industry standard protocols. Therefore, a person skilled in the art can develop a protocol in accordance with well-known techniques, which allow the transfer of unsolicited data to occur between the satellite gate 72 and the access point 70, such as through the use of a broad response In Figure 6, a simple fast network browser 20 is shown coupled to a distributed substitute server 68. However, in the preferred embodiment, the access point 70 serves a plurality of users. In addition, the satellite gate 72 can serve a plurality of SML access point units 70. In one embodiment, the access point 70 is consolidated within a single accommodation. This housing is coupled to an antenna, which is placed external to a building in which the housing is placed. A local area network couples a plurality of fast network browsers 20 to the housing. In another embodiment, the access point 70 is in the same machine or housing in which the network fast scanner 20 operates. In yet another embodiment, the functionality and modules of the access point 70 are distributed through a plurality of computing units. In general, the functions and modules of the access point can be distributed through entities on one side of this link and the gate functions and modules can be distributed through entities on the other side of the channel. It is not necessary that the access point or gate be coupled directly to the target link and intermediate entities just as this target link can separate the access point from the gate. The same techniques described here can be applied to the other external files, even if the probability of a subsequent request for those files is less than the probability of requests for the objects online. For example, many pages of the network contain hypertext links to other network pages, which the user "^ EaS" - * - - ^ can be selected for access. A homepage for a manufacturing company can have a hypertext link to a sample page, a product information page, a company information page and a press publication page. A user with access to the homepage is likely to reasonably have access to one of the pages named by the hypertext links. After all the online objects are retrieved by the satellite gate 72, the gate can begin the search for forecasting of the network pages linked and transferred to the access point 70 in a similar manner as the online objects. The amount of data can be limited to prevent an endless data match. If the user requests one of the previous search links as a prediction, he receives the information directly from the access point 70, thus avoiding the round trip delay associated with the use of the wireless link. In general, the previously searched objects can be text or digital data files, images, sound clips, program modules, data packages with external functions or any of them. Although the above example was described in terms of a fast network browser 20 with access to the network server over the Internet, the principles of the invention can be applied in many situations where a data terminal requests a data file containing a reference to an external data file on a data network that has a link that introduces a substantial delay. In such a case, the request unit can be any digital equipment queue which can generate a file request and the response unit can be any type of digital equipment that can transfer a file. For example, the Internet 24 shown in the figures may be a public or private local area network or a wide area network, in addition to the Internet. Thousands of alternative modalities will be readily apparent to an expert in the subject of the examination of the description. For example, although the preferred embodiment was shown with reference to a satellite link, the teachings of the invention can be directly applied to any link that introduces a significant delay such as a wire line link or a wireless link. In addition, as noted above, the use of the invention reduces the amount of data flowing from the access point to the gate. This reduction can be important even in those systems where the path delay between the access point and the gate is not substantial. For example, cable modems (modulator demodulator) are highly asymmetric links. The downstream link Fc < ÍfeJg .. from the Internet the user has a sufficiently high bandwidth, while the link upstream from the user to the Internet has a very limited bandwidth. Therefore, even if the delay is not an emergency, it may be advantageous to incorporate a substitute server in order to reduce the flow of upstream traffic. The invention can be realized in other specific forms without departing from its spirit or essential characteristics. The described mode will be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes within the meaning and range of equivalence of the claims will be considered within its scope. ..- mea '**.

Claims (15)

1. In an Internet access system, which includes a communication link, this communication link has a customer side and a side of the server, which is remote from the side of the server, the method of processing a request from a customer for a document, which includes an online object, this customer request is generated by a client and addressed to a document server, this document comprises a base component, which includes a reference to the object online, the method comprises: on the side of the client of the communication link: a.) receive the request of the clience and forward this request on the communication link to the side of the server; on the side of the communication link server: b.) receive the client's request, and forward this request to the server of the document on the Internet; c.) receive the base component from the document server, analyze this base component to identify the reference to the object and send forward To the base component on the communication link at the client's side for delivery to the client; and d.) Pre-search the online object of the document server, using the reference identified in step (c), and without waiting for the client to request the object, forward the object over the communications link to the client's side, for delivery to the customer.

2. The method of claim 1, further comprising the steps of., On the client side of the communication link: receiving and saving the object sent in step (d); and in response to a client request for the object, forward the object to the client.

3. The method of claim 2, further comprising the step of intercepting the client's request for the object that is transmitted over the communication link.

4. The method of claim 1, wherein the communication link is a satellite link, and the method avoids a delay normally associated with sending the client's request for the object on the satellite link.

5. The method of claim 4, wherein step (a) is performed by an executable component that goes to a user access point to the satellite link, and steps (b) -d) are performed by a gate component from the satellite to the Internet.

6. The method of claim 1, further comprising repeating step (d) for each of the plurality of additional online objects of the document.

7. The method of claim 1, wherein step (a) comprises communicating with a fast network scanning program, which uses a standard Internet protocol.

8. The method of claim 1, wherein the document includes a hypertext link to a second document, and the method further comprises pre-searching the second document on the side of the server, and forwarding this second document to the customer's side.

9. In a document-retrieval system, client-server type, in which the online objects of the documents are requested and retrieved separately from the base components of these documents, a distributed system to reduce a performance degradation, caused by a communication link, the distributed system comprises: a first component, which operates on the side of the client of the communication link and communicates with customers, this first component is adapted to receive requests for documents from clients and forward these requests on the communication link for the process, - and a second component, which operates on the side of the communication link server and communicates with the document servers, this second component is adapted to receive requests for documents from the first component over the communication link and to send forward the requests in the servers d e documents, the requests cause the document servers to return to the base components of the requested documents; in which this second component processes the base components returned by the document servers by at least (i) analyzing the base components to identify references to the objects online, di) pre-fetching the objects online and (iii) forward the online objects previously searched for the first component, without waiting for the client's requests for the objects in line, - and in which the first component stores the previously searched inline objects, received from the second component, in a cache, and responds to object requests from clients, by forwarding objects online to. the clients from the cache.

10. The distributed system of claim 9, in which the first component intercepts a client request for an object, when the object resides within the cache, this first component thus reduces the traffic on the communication link.

11. The distributed system of claim 9, wherein the communication link is a satellite link, and the first and second components reduce a normally associated delay, with requests for the in-line objects on the satellite link.

12. The distributed system of claim 11, wherein the first component operates at a customer access point to the satellite link, and the second component is part of the satellite gate system to the Internet.

13. The distributed system of claim 9, wherein the communication link is a cable-based link, to provide access to the Internet by the cable modem.

14. The distributed system of claim 9, wherein the document retrieval system is a hypertextual system, and the second component is further configured to pre-fetch a document, which has a hypertextual reference within a requested document.

15. The system of claim 9, wherein the first component and the second component carry out standard protocols of the World Wide Web worldwide network for communication with the clients and the document servers, respectively. SUMMARY OF THE INVENTION In an Internet access system, which includes a satellite link, a distributed substitute server (68) is provided, which reduces a delay associated with the retrieval of online objects from the pages of the network. This distributed substitute server (68) includes a component (70) of the access point and a component (72) of the satellite gate. This component (70) of the access point operates on the side of the client (quick review) of the satellite link and communicates with the network rapid examiners (20A-20N). The component (72) of the satellite gate operates on the side of the Internet of the satellite link and communicates with the network servers (26). As the network page is retrieved over the satellite link, the component (72) of the satellite gate analyzes the base file component of the network page to identify any reference to the online objects of the network page, and Pre-search each of the objects online. The distributed substitute server thus eliminates the delays normally associated with (a) the wait for the rapid examiner (20) of the network to receive the base component and request one or more objects, and (b) the wait for the object requests of the rapid examiner, which will be transmitted over the satellite link. The objects aaap previously searched are transmitted over the satellite link to the component (70) of the access point, which, in turn, stores the objects previously searched in the cache (71) of the object. When a network fast browser (20) requests an object online, the component (70) of the access point checks the cache memory (71), and if the object resides there, it returns this object to the fast browser (20) without forwarding the object request on the satellite link. The traffic on the forward satellite link is thus reduced. The method carried out by the distributed substitute server (68) can also be used to reduce delays and traffic over other types of links, which include non-wireless links.