AU8926501A - Distributed process for synchronizing the delivery of data from multiple web servers - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: International Business Machines Corporation Armonk New York 10504 United States of America Rabindranath Dutta Steven Michael French Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Distributed Process for Synchronizing the Delivery of Data From Multiple Web Servers The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c AUS92000043OUS1 -I DISTRIBUTED PROCESS FOR SYNCHRONIZING THE DELIVERY OF DATA FROM MULTIPLE WEB SERVERS Background of the Invention 1. Field of the Invention The present invention generally relates to computer systems, and more particularly to a method, system and program for delivering data across a computer network, such as the Internet, using multiple servers.

2. Description of Related Art A generalized client-server computing network 2 is shown in Figure 1. Network 2 has several nodes or servers 4, 6, 8 and 10 which are interconnected, either directly to each other or indirectly through one of the other servers.

Each server is essentially a stand-alone computer system (having one or more processors, memory devices, and communications devices), but has been adapted (programmed) for one primary purpose, that of providing information to individual users at another set of nodes, or workstation clients 12. A client is a member of a class or group of computers or computer systems that uses the services of another class or group to which it is not related. Clients 12 can also be stand-alone computer systems (like personal computers, or PCs), or "dumber" systems adapted for limited use with network 2 (like network computers, or NCs), as well 00.0:25 as Internet-enabled devices such as cell phones or televisions. A single, physical computer can act as both a AUS92000043US1 -2 server and a client, although this implementation occurs infrequently.

The information provided by a server can be in the form of programs which run locally on a given client 12, or in the form of data such as files that are used by other programs. Users can also communicate with each other in real-time as well as by delayed file delivery, users connected to the same server can all communicate with each other without the need for the network 2, and users at different servers, such as servers 4 and 6, can communicate with each other via network 2. The network can be local in nature, or can be further connected to other systems (not shown) as indicated with servers 8 and The construction of network 2 is also generally applicable to the Internet. In the context of a computer network such as the Internet, a client is a process a program or task) that requests a service which is provided by another program. The client process uses the requested service without having to "know" any working details about the other program or the service itself. Based upon requests by the user, a server presents filtered electronic information to the user as server responses to the client process.

Conventional protocols and services have been established for the Internet which allow the transfer of various types of information, including electronic mail, AUS920000430US1 3 simple file transfers via FTP (file transfer protocol), remote computing via Telnet, "gopher" searching, Usenet newsgroups, and hypertext file delivery and multimedia streaming via the World Wide Web (WWW). A given server can be dedicated to performing one of these operations, or running multiple services. Internet services are typically accessed by specifying a unique address, or universal resource locator (URL). The URL has two basic components, the protocol to be used, and the object pathname. For example, the URL "http://www.uspto.gov" (home page for the United States Patent Trademark Office) specifies a hypertext transfer protocol ("http") and a pathname of the server ("www.uspto.gov"). The server name is associated with a unique numeric value (a TCP/IP address, or "domain").

The present invention relates to the delivery of computer files that are distributed on a network like the Internet, but is particularly applicable to the WWW, which provides files that are conveniently linked for user access.

For example, as illustrated in Figure 2, a group 14 of files or pages 16a-16h are interrelated by providing hypertext links in each of the files (group 14 may thus be considered a typical "web site"). A hypertext link is an object an image or text) that is viewable on the workstation's display 18, which can be selected by the user using a pointing device or "mouse") and which then automatically S• instructs client workstation 12 to request another page associated with that particular hypertext link issue another URL). A hypertext link may appear as a picture, or as a word or sentence, possibly underlined or otherwise AUS92000043US1 4 accentuated to indicate that it is a link and not just normal, informative text.

A WWW page may have text, graphic (still) images, and even multimedia objects such as sound recordings or moving video clips. A hypertext page, if more than just text, is usually constructed by loading several separate files, e.g., the hypertext file "main.html" might include a reference to a graphic image file "picture.gif" or to a sound file "beep.wav". When a client workstation 12 sends a request to a server for a page, such as page 16a, the server first transmits (at least partially) the main hypertext file associated with the page, and then the client loads and renders, either sequentially or simultaneously, the other files associated with the page. A given file may be transmitted as several separate pieces via TCP/IP protocol.

The constructed page is then displayed on the workstation monitor 18 as shown in Figure 2. A page may be "larger" than the physical size of the monitor screen larger than the software-programmed "window" provided for viewing the page), and techniques such as scroll bars are used by the viewing software (the web browser) to view different portions of the page.

As the number of users and service providers on the Internet has dramatically increased, problems have arisen regarding the distribution of so much information across S" such a physically and logically complex network. One method for efficiently distributing the delivery workload uses multiple web servers. For example, many web sites include AUS92000043OUS1 5 advertisements (such as "banners") that are electronically stored at servers separate from the web site server. These "ad servers" provide a convenient source to manage advertisement generation, delivery and monitoring. Another example of the use of multiple web servers is the redundant storage of information for a single web site at different server locations. This approach allows a company to distribute information across the world with improved speed.

The development of Network Attached Storage (NAS) and Storage Area Networks (SAN) has created a situation where very large volumes of data can be kept in centrally managed networks of storage devices away from the main HTTP server to which a user connects. These networks are similar in concept to a "server farm" (but integrated at a lower level) in which the servers are connected via high speed LANs to one another.

While these techniques are helpful, there are still t problems with the synchronization of information delivery.

Consider a web page 20 such as that shown in Figure 3 (URL http://wwww.yahoo.com/mainpage.html) containing two text fields 22 and 24, four images 26 (from www.doubleclick.com/image_ad.gif), 28 (from www.akamai.com/2323/image_akamai.gif), 30 (from www.yahooserverl.com/image_3.jpg), and 32 (from www.yahooserver2.com/image_4.jpg). In this example, when page 20 is downloaded by a web client, the following sequence of events takes place: AUS920000430US1 6 ooo 25 Step 1: the page "mainpage.html" is retrieved from the server at www.yahoo.com (the main HTTP server); Step 2: The main HTTP server returns the page "mainpage.html" to the client and the client begins rendering the page; (steps 3a through 3c are effectively performed in parallel) Step 3a: the client renders text field 22 to the screen, followed by text field 24; Step 3b: the client requests "image_ad.gif" from the server at doubleclick.com followed by rendering to screen; Step 3c: the client requests "image_akamai.gif" from the server at akamai.com followed by rendering to screen; Step 3d: the client requests "image_3.jpg" from the server at yahooserverl.com followed by rendering to screen; and Step 3e: the client requests "image_4.jpg" from yahooserver2.com followed by rendering to screen.

Following Step 3 (a through e) the full content of page is observed by the user. Because of the asynchronous distributed nature of delivery, however, there is no control or predictability on the order in which contents arrive at the client or appear on the client display screen. So, with prior art web page construction, the text field 24 ("As you can see from the picture of Mount Everest, in summer it is one of a group of clustered mountains and is always covered by snow") may appear on the screen, while the picture 28 of AUS920000430US1 7 Mount Everest still has 20 seconds more to download'and render.

It is possible to delay rendering till all content has been downloaded using extensions to a web browser, or appropriate scripts or applets, such that all of the content can effectively be presented to the user simultaneously.

Generally, however, it is desirable to make whatever content has been downloaded available to the client. Local scripting or programs in the client for achieving this are not a good idea, particularly in thin clients like palm-top computers, web phones, etc., where such complex interpretation or execution may not be feasible. It would, therefore, be desirable to devise an improved method of delivering content to a web client in a more synchronized manner. It would be further advantageous if the delivery of different parts of an electronic document could be coordinated in such a manner as to take advantage of existing network infrastructure, so as to reduce cost and simplify deployment.

.0 AUS920000430US1 8 Summary of the Invention It is therefore one object of the present invention to provide an improved method of accessing information that is retrieved across a network, such as the Internet.

It is another object of the present invention to provide such a method which utilizes multiple servers to efficiently distribute the workload in delivering the contents of an electronic document to a client.

It is yet another object of the present invention to provide a method of synchronizing the delivery of content from multiple web servers which takes advantage of existing network connectivity infrastructure.

The foregoing objects are achieved in a method of delivering data across a computer network, generally comprising the steps of issuing a request from a first node *of the computer network to a second node of the computer network using a first communications path, the request identifying an electronic document composed of a plurality of objects, and chronologically synchronizing transmission :20 of at least one of the electronic document objects to the first node, said synchronizing step using a second communications path between the second node and a third node S•of the computer system, wherein the third node stores at o...o S"least one other of the electronic document objects. In the illustrative implementation, the-second communications path has a transmission speed which is faster than a transmission speed of the first communications path. In the context of a AUS920000430US1 9 client-server network such as the Internet, the first node is a client workstation, and the second and third nodes are network servers. The synchronizing may be accomplished by chronologically ordering two or more of the electronic document objects. Synchronization information can be embedded within a primary file associated with the electronic document.

The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following detailed written description.

*e AUS92000043US1 10 Brief Description of the Drawings Thenovel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: Figure 1 is a diagram of a conventional computer network, including interconnected servers and client workstations; Figure 2 is a pictorial representation of the retrieval of an object from a set of linked objects residing on the network, such as a page on the World Wide Web; 5 Figure 3 is an illustration of a completely rendered web page showing related features such as text fields and .i images; Figure 4 is a block diagram of a simplified network arrangement according to an exemplary implementation of the oe o present invention; and Figure 5 is a chart illustrating the logical flow of browser/server interaction according to one implementation of the present invention.

AUS92000043OUS1 11 Description of an Illustrative Embodiment With reference now to Figure 4, there is depicted one embodiment 40 of a network arrangement constructed in accordance with the present invention. Network 40 is described in the context of the Internet, but the invention may be implemented in other networks, so this reference should not be construed in a limiting sense.

Network 40 is generally comprised of a main web server 42, one or more secondary or supplemental web servers 44, and a client workstation 46. Main web server 42 is connected by a relatively high-speed link 48 to servers 44, such as those of Akamai or Doubleclick, or Network Attached Storage (NAS). However, client 46 is attached to the servers via a slow link 50. While client 46 may be a desktop workstation, those skilled in the art will appreciate that it may as well be a personal digital assistant (PDA), web-enabled cell phone, Internet-enabled o television, a game console, etc.

Commercial enterprises that operate servers 42 and 44 typically have large investments in network connectivity.

Servers 42 and 44 may be interconnected, for example, using high-speed fiber optic links. Client 46, in contrast, is typically connected to the Internet using a telephone modem.

The present invention takes advantage of the different speeds of these links, allowing ordering to be imposed on web content downloaded from multiple servers in a fashion that is transparent to the user.

AUS920000430US1 12 Consider again the example of Figure 3. According to the present invention, web page 20 is more efficiently constructed in the following sequence of steps: Step 1: client 46 requests "mainpage.html" from the server at www.yahoo.com, main server 42 (while this file "mainpage.html" contains the complete text associated with text field 22, text field 24 is an embedded HTML file with an object tag, that is, text field 24 is provided as an HTML file inside an HTML file); (steps 2a and 2b are effectively performed in parallel) Step 2a: main web server 42 returns the page "mainpage.html" to client 46 and the client starts rendering the page; Step 2b: main web server 42 informs the supplemental server(s) 44, over fast link 48, that client 46 will be requesting the indicated image files (the identity of client 42 can be tracked via "cookies," or URL rewriting); (steps 3a through 3f are effectively performed in parallel) Step 3a: client 46 renders text field 22 on the display screen of the workstation; Step 3b: client 46 requests "image_ad.gif" from the server at doubleclick.com followed by rendering to the screen; Step 3c: client 46 requests "image_akamai.gif" from the server at akamai.com followed by rendering to the screen;

I

I. AUS920000430US1 13 Step 3d: client 46 requests "image_3.jpg" from the server at yahooserverl.com followed by rendering to the screen; Step 3e: client 46 requests "image_4.jpg" from the server at yahooserver2.com followed by rendering to the screen; Step 3f: client 46 requests the embedded object (HTML file) for text field 24 from the server at www.yahoo.com (but this main server 42 does not immediately send that text object); Step 4: after the supplemental servers 44 (akamai, doubleclick, yahooserverl and yahooserver2) finish sending their data to client 46, they inform main server 42, again over fast link 48, that they have sent the identified data to client 46 (in an alternative implementation this confirmation can be sent shortly before the transmission of data to the client, anticipating its delivery); Step5: after main server 42 receives the confirmation 20 from the supplemental servers, it sends the requested file corresponding to text field 24 to client 46, followed by rendering to screen.

The text "Mount Everest is the highest mountain in the world" will appear first on the screen, followed by the ,:25 images. Then, based on the ordering information that is embedded within web page 20 in accordance with the present invention, and only after the images have been rendered, the text field 24 appears ("As you can see from the picture of AUS92000043US1 -14 Mount Everest in summer it is one of a group of clustered mountains and is always covered by snow."). Hence the picture of Mount Everest appears before an explicit narrative reference to the picture appears. Thus distributed data is delivered in a chronologically synchronized manner. Issues such as timeouts are beyond the scope of the present invention, but their resolution will be apparent to one skilled in the art upon reference to this disclosure.

The foregoing process may be further understood with reference to the flow chart of Figure 5. First, the browser executes a "GET X" to the content server The content server records the client properties associated with the request A determination is then made as to whether the client type is known to the server If so, then the server simply sends the requested item to the browser If not, however, then the server may append an a appropriate JavaScript to the requested object The server then records the time difference between the send and o*°a.

20 the receive and a further determination is made as to whether synchronization is necessary If no synchronization is necessary, then the notification can merely be sent to the appropriate server without any synchronization steps If synchronization is required, further steps are taken to synchronize the delivery (68).

The synchronization of page elements may be achieved in various ways. As mentioned above, ordering information may AUS920000430US1 15 be embedded within the electronic document, using html-type tags. Alternatively, the synchronization information may be part of the URL for the object which is to be synchronized. For example, the picture of Mount Everest in Figure 3 could be retrieved using the URL "http://server3.akamai.com/bigimage.jpg/DELIVERY INFO" where "DELIVERY INFO" corresponds to the synchronization information. The servers are appropriately programmed to provide the necessary notifications based on this ordering information. Network 40 may otherwise use conventional protocols and agents to route information (data and messages) between the various nodes. If the client has low display resolution, some images (especially those that are configured to display at the bottom of the page) may be out of the initial visible area and would therefore be less important to synchronize with the rest of the objects that display on the initially visible portion of the page. There are several ways to dynamically determine client-side video device characteristics. For example, a small program (or script) could be downloaded from the server and executed to return the results to the server (or store the results in a cookie for reuse by the server at a later time).

Alternatively, characteristics may be inferred from the data in the optional HDTP "accept" tag which is supplied by the 25 client browser. The browser type and operating system are S•commonly sent in the "user-H" field of the first request from the client to the server, so that the server can use this information. Delivery synchronization could be tied to client device characteristics; for example, clients with low resolution monitors might not require delivery AUS92000043US1 16 synchronization of any images that would be difficult to read.

The present invention thus provides a method of controlling the timely presentation of the various elements in an electronic document which is to be transmitted across a network. The invention provides this functionality using existing hardware, and takes advantage of the connectivity infrastructure for the network. The invention further allows ordering of events in the browser, with little client workstation overhead, facilitating execution of programs/scripts that are dependent on the actual objects images) on the page at that time.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. For example, while the illustrative embodiment has been described in the context of a client-server network, those skilled in the art will I.appreciate that it can be practiced in a peer-to-peer network as well. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined in the appended claims.

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Claims (5)

19- 1 9. A networked computer system comprising: 2 a first node; 3 a second node; 4 a third node; a first communications path for transmitting data to 6 said first node; 7 a second communications path for transmitting data 8 between said second and third nodes; 9 means for receiving a request from said first node at said second node using said first communications path, the 11 request identifying an electronic document composed of a 12 plurality of objects; and 13 means for chronologically synchronizing transmission of 14 at least one of the electronic document objects to said first node, said synchronizing means using said second 16 communications path, wherein said third node stores at least 17 one other of the electronic document objects. 1 10. The networked computer system of Claim 9 wherein 2 said second communications path has a transmission speed S3 which is faster than a transmission speed of said first 4 communications path. ooeoo° 1 11. The networked computer system of Claim 9 further 2 comprising means for transmitting the at least one 3 electronic document object to said first node in response to 4 said synchronizing means. *eeo AUS920000430US1 20 1 12. The networked computer system of Claim 9 wherein 2 said synchronizing means chronologically orders two or more 3 of the electronic document objects. 1 13. The networked computer system of Claim 9 wherein 2 said synchronizing means uses synchronization information 3 embedded within a primary file associated with the 4 electronic document. 1 14. The networked computer system of Claim 9 wherein 2 said synchronizing means transmits a message from said 3 second node to said third node identifying said first node 4 as a recipient of one or more of the electronic document objects. 1 15. The networked computer system of Claim 14 wherein 2 said synchronizing means further informs the second node of transmission of the one or more electronic document objects 9 from said third node. 1 16. The networked computer system of Claim 9 wherein 2 said synchronizing means is based on at least one device 3 characteristic of said first node. o AUS92000043OUS1 21 1 17. A computer program product comprising: 2 a computer-readable storage medium; and 3 program instructions stored on said storage medium for 4 receiving a request from a first node of a computer network at a second node of the computer network using a 6 first communications path, the request identifying an 7 electronic document composed of a plurality of objects, and 8 (ii) chronologically synchronizing transmission of at least 9 one of the electronic document objects to the first node, using a second communications path between the second node 11 and a third node of the computer system, wherein the third 12 node stores at least one other of the electronic document 13 objects. 1 18. The computer program product of Claim 17 wherein 2 the second communications path has a transmission speed 3 which is faster than a transmission speed of the first communications path. 1 19. The computer program product of Claim 17 wherein S2 said program instructions are further for transmitting the 3 at least one electronic document object to the first node 4 based on said synchronizing of the at least one electronic •5 document object. 1 20. The computer program product of Claim 17 wherein .ooo.. 2 said program instructions synchronize the transmission of 3 the at least one electronic document object by S4 chronologically ordering two or more of the electronic document objects. 22 1 21. The computer program product of Claim 17 wherein said program 2 instructions synchronize transmission of the at least one 3 electronic document object using synchronization information 4 embedded within a primary file associated with the electronic document. 1

22. The computer program product of Claim 17 wherein 2 said program instructions synchronize transmission of the at 3 least one electronic document object by transmitting from 4 the second node a message to the third node identifying the first node as a recipient of one or more of the electronic 6 document objects. 1

23. The computer program product of Claim 22 wherein 2 said program instructions synchronize transmission of the at 3 least one electronic document object by having the third node inform the second node of transmission of the one or more electronic document objects. *6 o6 6b** i 624. The computer program product of Claim 17 wherein 2 said program instructions synchronize transmission of the at least one electronic document based on at least one device characteristic of the first node. ee e ee0.. S. -23- A method of delivering data across a computer network, said method being substantially as described herein with reference to Figs. 3 to

26. A networked computer system substantially as described herein with reference to Figs. 3 to

27. A computer program product substantially as described herein with reference to Figs. 3 to DATED this Fifth Day of November, 2001 International Business Machines Corporation Patent Attorneys for the Applicant SPRUSON FERGUSON 9 6 .99 o S *o l ft* [R:\LIBCC]281 .doc:caa