Method and apparatus to retrieve information in a network
Contents
1. B1 3 2004 Hendren III 711 138 6 792 461 B1 9 2004 Hericourt 709 225 6 792 463 B1 9 2004 Lamberton et al 709 227 6 839 881 B2 1 2005 Myers etal 715 513 6 871 236 B2 3 2005 Fishman etal 709 246 2001 0056476 Al 12 2001 Benayoun etal 709 218 2003 0043844 Al 3 2003 Heller oo 370 466 FOREIGN PATENT DOCUMENTS CN 1294712 A 5 2001 WO 98 43177 Al 10 1998 OTHER PUBLICATIONS Netscape Communications Corporation Netscape Proxy Server Administrator s Guide Version 3 5 for Unix Mar 1998 from http developer netscape com docs manuals proxy html Introduction Table of Contents Chapters 5 and 9 pp 1 52 as printed Angel Lesson 129 Proxy Servers Apr 1999 Network Magazine vol 14 Iss 4 pp 27ff WinRoute Pro 3 0 User s Manual Tiny Software Inc 1999 Rubas WinProxy 1 4 User s Manual 1997 C2NET Software Inc Stronghold Web Server 2 4 1 Adminstration Guide Online Sep 1998 XP0022 147 14 37 pages Intel Corp Persistence Mechanisms Enabling today s dynamic e Business transactions White paper Online 2000 XP0022 14713 8 pages Alteon Websystems Virtual Matrix Architecture Scaling Web Ser vices for Performance and Capacity White paper Online Apr 2000 XP002191242 13 pages cited by examiner Primary Examiner Aaron Strange 74 Attorney Agent or Firm Kacvinsky Daisak PLLC 57 ABSTRACT An improved method a2. a first request for information is received over a first connection at block 302 The first request for information may be for example a request for a web page using an HTTP Get command in accordance with the HTTP Specification The first connection may be for example a connection between a client computer and an access device such as access device 106 The information may be retrieved over a second connection at block 304 The second connection may be for example a connection between an access device and a US 7 899 911 B2 5 server containing the requested information such as server 108 The access device may detect that the first connection has been terminated at block 306 The first connection may be terminated for various reasons such as intentionally by the user via a cancellation or refresh request sent from a browser at the client computer a break in the physical or logical connection between the client computer and access device and so forth The access device may receive a second request for the information over a third connection at block 308 The third connection may comprise for example a new connec tion between the client computer and the access device to replace the terminated first connection The access device may determine whether the second request matches the first request at block 310 The access device may send the infor mation over the third connection at block 312 in accordance with the determination
3. said second source address matches said first source address and determining whether said first information address matches said second information address 4 The method of claim 3 wherein said source addresses comprise Internet addresses and said information addresses comprise uniform resource locators 5 The method of claim 1 wherein said information com prises a hypertext markup language HTML file 6 The method of claim 1 wherein said information com prises an extensible markup language XML file 7 The method of claim 1 further comprising receiving a request to terminate said third connection and terminating said second and third connections 8 A method to retrieve information in a network compris ing receiving a first request for information from a first net work node at a second network node over a first connec tion sending said first request over a second connection to a third network node receiving a notice that said first connection is terminated prior to retrieval of said information over said second connection receiving said information over said second connection at said second network node receiving a second request for said information over a third connection at said second network node determining whether said second request matches said first request including whether said second request is from said first network node sending said information over said third connection to sa
4. the TCP connection toward the server open to receive the requested information In segment 4 a new TCP session is set up between the client computer and the web switch The client computer sends a request fora URL Since the TCP connection between the web switch and the server remains open a new TCP connection between the web switch and the server is not opened In segment 5 the web switch checks its information table to determine whether there is an outstanding URL request toward the server for the source IP address already If so the previous URL request is spliced with the new URL request As a result the web switch may avoid selecting a server opening a new connection and sending the new URL request to the selected server In segment 6 the web switch may receive the web page associated with the previous URL request The web switch may perform a validation process to ensure that the received web page is the same as the one requested in the new URL request the web page is timely and so forth Ifthe web page is valid the web switch may send the web page to the client computer If the web page is not valid a new server may be selected a connection opened with the server anda new URL request sent to the selected server In segment 7 the web switch may receive a request to terminate the connection between the client computer and the web switch Once it receives this request the web switch may terminate the open connection between
5. with one embodiment of the invention FIG 4 illustrates a message flow in accordance with one embodiment of the invention DETAILED DESCRIPTION In the following detailed description numerous specific details are set forth in order to provide a thorough understand ing ofthe embodiments ofthe invention It will be understood by those skilled in the art however that the embodiments of the invention may be practiced without these specific details Inother instances well known methods procedures compo nents and circuits have not been described in detail so as not to obscure the embodiments of the invention One embodiment of the invention may increase the speed by which information may be retrieved from a server The 20 25 30 35 40 45 50 55 60 65 2 server may be connected to an access device such as a load balancer web switch virtual private network gateway and so forth The access device may manage how information is stored and retrieved from the server For example a load balancer may operate to make multiple servers appear like a single high powered network resource to those accessing the array of servers It does this by selectively forwarding con nections to the many servers arrayed behind it in an equitable manner according to such factors as the server s operational health nature of the query and so forth The load balancer may check the operational health of a server by testing the server
6. US007899911B2 az United States Patent Jensen et al US 7 899 911 B2 Mar 1 2011 10 Patent No 45 Date of Patent 54 METHOD AND APPARATUS TO RETRIEVE INFORMATION IN A NETWORK 75 Inventors Kell Michael Jensen Gentofte DK Alex Agerholm Glostrup DK 73 Assignee Intel Corporation Santa Clara CA US Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 U S C 154 b by 1929 days 21 Appl No 09 877 928 22 Filed Jun 7 2001 65 Prior Publication Data US 2002 0188698 A1 Dec 12 2002 51 Int CI G06F 15 16 2006 01 52 US CL i2 rnenereermerenes 709 227 709 219 58 Field of Classification Search 709 202 709 226 219 227 228 203 See application file for complete search history 56 References Cited U S PATENT DOCUMENTS 5 802 292 A 9 1998 Mogul 709 203 5 852 717 A 12 1998 Bhide etal 709 203 5 991 306 A 11 1999 Burns etal 370 429 6 003 082 A 12 1999 Gampperetal 709 225 6 085 193 A 7 2000 Malkin et al 707 10 6 167 438 A 12 2000 Yates et al 709 216 6 185 625 B1 2 2001 Tsoetal 709 247 6 247 050 B1 6 2001 Tsoetal we 709 224 6 421 733 B1 7 2002 Tsoetal 709 246 6 438 652 B1 8 2002 Jordan etal 711 120 6 553 420 B1 4 2003 Kargeretal 709 226 6 701 415
7. a tions and changes as fall within the true spirit of the embodi ments of the invention The invention claimed is 1 A method to retrieve information comprising receiving a first request for information from a client at a network node over a first connection establishing a second connection to retrieve said informa tion detecting that said first connection is terminated prior to retrieval of said information over said second connec tion retrieving said information over said second connection US 7 899 911 B2 7 receiving a second request at the network node for said information over a third connection determining whether said second request matches said first request including whether said second request is from said client sending said information over said third connection in accordance with said determination and deleting said information at the network node upon deliv ery of said information to said client 2 The method of claim 1 wherein said first request com prises a first source address and a first information address further comprising storing said information with said first source address and said first information address in an infor mation table prior to receiving said second request 3 The method of claim 2 wherein said second request comprises a second source address and a second information address and said determining comprises searching said information table to determine whether
8. at block 310 After retrieving the information at block 304 the access device may store the information in memory such as memory 210 or disk storage 218 In one embodiment of the invention the first request may comprise a first source address and a first information address The access device may store the first source address the first information address and the informa tion in an information table The access device may receive a second request at block 308 The second request may com prise a second source address and a second information address The access device may search the information table to determine whether the second source address matches the first source address and the first information address matches the second information address If both match the access device may retrieve the information corresponding to the first source address and first information address and send the information to the client computer over the third connection In one embodiment of the invention the source address may comprise an IP address the information address may comprise a URL and the information may comprise a web page such as an HTML or XML file It can be appreciated however that the source address information address and information may be in other formats in accordance with a desired set of protocols and still fall within the scope of the invention Once the client computer receives the requested informa tion the client com
9. communications protocols services and operating proce dures for example In one embodiment of the invention I O adapter 204 may operate for example in accordance with the Transmission Control Protocol TCP as defined by the IETF standard 7 RFC 793 adopted in September 1981 and the Internet Protocol IP as defined by the IETF standard 5 RFC 791 adopted in September 1981 both available from www ietf org although the embodiments of the invention are not limited to this context I O adapter 204 also includes appropriate connectors for connecting I O adapter 204 with a suitable communications medium I O adapter 204 may receive communication signals over any suitable medium such as copper leads twisted pair wire co axial cable fiber optics radio frequencies and so forth The operations of systems 100 and 200 may be further described with reference to FIG 3 and its accompanying examples Although FIG 3 as presented herein may include a particular processing logic it can be appreciated that the processing logic merely provides an example of how the general functionality described herein can be implemented Further each operation within a given processing logic does not necessarily have to be executed in the order presented unless otherwise indicated FIG 3 is a block flow diagram of the programming logic performed by an information management component in accordance with one embodiment of the invention As shown in FIG 3
10. he same file may be stored on a number of different servers Whenever a user sends a request to access a file stored on a server the request may be intercepted by a network access device such as a load balancer or web switch The net work access device may operate to coordinate and control how information is stored and accessed in order to optimize overall network performance Optimized performance might be realized for example in lower access times for informa tion stored on the servers Due to the increasing demands for lower access times it can be appreciated that there is a sub stantial need for technologies that may retrieve information faster from a server over a network BRIEF DESCRIPTION OF THE DRAWINGS The subject matter regarded as embodiments of the inven tion is particularly pointed out and distinctly claimed in the concluding portion of the specification Embodiments of the invention however both as to organization and method of operation together with objects features and advantages thereof may best be understood by reference to the following detailed description when read with the accompanying draw ings in which FIG 1 is a system suitable for practicing one embodiment of the invention FIG 2 is a block diagram ofan access device in accordance with one embodiment of the invention FIG 3 is a block flow diagram of the programming logic performed by an information management component in accordance
11. id first network node and deleting said information at the second network node upon delivery of said information to said first network node 9 The method of claim 8 wherein said first request com prises a first source address and a first information address further comprising storing said information with said first source address and said first information address in an infor mation table at said second network node prior to receiving said second request 20 25 30 35 40 45 50 55 8 10 The method of claim 9 wherein said second request comprises a second source address and a second information address and said sending comprises searching said information table to determine whether said second source address matches said first source address determining whether said first information address matches said second information address and sending said information in accordance with said determi nation 11 The method of claim 9 wherein said source addresses comprise Internet addresses and said information addresses comprise uniform resource locators 12 The method of claim 8 wherein said information com prises a hypertext markup language HTML file 13 The method of claim 8 wherein said information com prises an extensible markup language XML file 14 The method of claim 8 further comprising receiving a request to terminate said third connection and terminating said second and third co
12. machine readable storage devices through various I O controllers which are accessible by pro cessor 202 and which are capable of storing a combination of computer program instructions and data Memory 210 is accessible by processor 202 over bus 208 and includes an operating system 216 a program partition 212 and a data partition 214 In one embodiment of the invention operating system 216 may comprise an operating system sold by Microsoft Corporation such as Microsoft Windows 95 98 2000 and NT for example Program par tition 212 stores and allows execution by processor 202 of program instructions that implement the functions of each respective system described herein Data partition 214 is accessible by processor 202 and stores data used during the execution of program instructions Inone embodiment ofthe invention program partition 212 contains program instructions that may be collectively referred to herein as an information management component Although this embodiment of the invention uses one compo nent it can be appreciated that the functionality performed by this component may be combined with other components or separated into additional components and still fall within the scope of the invention I O adapter 204 may comprise a network adapter or net work interface card NIC configured to operate with any suitable technique for controlling communication signals between computer or network devices using a desired set of
13. n determining whether said second request matches said first request by searching said informa tion table to determine whether said second source address matches said first source address and determining whether said first information address matches said second informa tion address 18 The article of claim 15 wherein the stored instructions when executed by a processor further result receiving a request to terminate said third connection and terminating said second and third connections
14. nd apparatus to retrieve information over a network is described 18 Claims 4 Drawing Sheets receive a first request for information 302 over a first connectron I retrieve the information over a second connection LA detect that tha first connection is terminated receive a second request for the information over a third connection i determine whether the second request matches the first request connection in accordance with the sending the information over the third 312 determination US Patent Mar 1 2011 Sheet 1 of 4 US 7 899 911 B2 o 2 gt CD e o Wu D 2 e t FIG 1 US Patent Mar 1 2011 Sheet 2 of 4 US 7 899 911 B2 202 204 206 iO Operator 212 iti 214 Data Paritions FIG US Patent Mar 1 2011 Sheet 3 of 4 Start receive a first request for information over a first connection retrieve the information over a second connection detect that the first connection is terminated receive a second request for the information over a third connection determine whether the second request matches tne first request sending the information over the third connection in accordance with the determination End US 7 899 911 B2 300 304 306 308 310 312 FIG 3 US Patent Client Mar 1 2011 Sheet 4 of 4 WaoSwich Servar SYN 7 SYN ACK ACK D REQ1 hesdec z M ACK REQ8 header body b R QS vod
15. nnections 15 An article comprising a storage medium said storage medium including stored instructions that when executed by a processor result in receiving a first request for information from a client at a network node over a first connection establishing a second connection to retrieve said information detecting that said first con nection is terminated prior to retrieval of said informa tion over said second connection retrieving said infor mation over said second connection receiving a second request for said information at the network node over a third connection determining whether said second request matches said first request including whether said second request is from said client sending said informa tion over said third connection in accordance with said determination and deleting said information at the net work node upon delivery of said information to said client 16 The article of claim 15 wherein said first request com prises a first source address and a first information address and the stored instructions when executed by a processor further result in storing said information with said first source address and said first information address in an information table prior to receiving said second request 17 The article of claim 16 wherein said second request comprises a second source address and a second information address and the stored instructions when executed by a processor further result i
16. o the client computer without having to open a new connection to the server This embodiment of the invention provides several advan tages For example this embodiment of the invention avoids the latency associated with re establishing a connection US 7 899 911 B2 3 between the load balancer and the server The load balancer may also avoid having to go through the selection process to select a particular server from the group or cluster of servers In addition the server would not have to retrieve the infor mation twice thereby releasing resources for other uses Itis worthy to note that any reference in the specification to one embodiment or an embodiment means that a particu lar feature structure or characteristic described in connec tion with the embodiment is included in at least one embodi ment of the invention The appearances of the phrase in one embodiment in various places in the specification are not necessarily all referring to the same embodiment Referring now in detail to the drawings wherein like parts are designated by like reference numerals throughout there is illustrated in FIG 1 a system suitable for practicing one embodiment of the invention FIG 1 is a block diagram of a network 100 Network 100 may comprise a client computer 102 a network 104 an access device 106 and a server 108 In one embodiment of the invention server 108 may be part of an array of servers connected together by a network fo
17. puter may send a request to terminate the third connection between the client computer and the access device The access device may then terminate the second connection between the access device and the server and the third connection in accordance with the particular protocol used FIG 4 illustrates a message flow in accordance with one embodiment of the invention As shown in FIG 4 a TCP session is set up between a client computer and an access device and the access device and a server The access device may be for example a web switch A web switch may operate similar to a load balancer In segment 1 a TCP session may be set up between the client computer and the web switch In this example of a message flow there is no TCP connection set up between the web switch and the server yet During segment 1 the client computer may send the URL for the desired web page Once the access device has received and stored the requested URL the web switch may enter segment 2 Seg ment 2 may include for example selecting a server having the requested web page The web switch may set up a TCP connection toward the selected server and passes the URL request to the server over the opened connection In segment 3 the TCP connection from the client computer to the web switch is terminated prior to receiving the requested information from the server The web switch how 20 25 30 35 40 45 50 55 60 65 6 ever keeps
18. r example FIG 2 is a block diagram of a system in accordance with one embodiment of the invention FIG 2 illustrates a system 200 that may be representative of an access device such as access device 106 As shown in FIG 2 system 200 may comprise a processor 202 an input output I O adapter 204 an operator interface 206 a memory 210 and a disk storage 218 Memory 210 may store computer program instructions and data The term program instructions may include com puter code segments comprising words values and symbols from a predefined computer language that when placed in combination according to a predefined manner or syntax cause a processor to perform a certain function Examples of a computer language may include C C and assembly Processor 202 executes the program instructions and pro cesses the data stored in memory 210 Disk storage 218 stores data to be transferred to and from memory 210 I O adapter 204 communicates with other devices and transfers data in and out of the computer system over connection 224 Examples of other devices may include a microphone and display such as microphone 106 and display 102 respec tively Operator interface 206 may interface with a system operator by accepting commands and providing status infor mation All these elements are interconnected by bus 208 which allows data to be intercommunicated between the ele ments Processor 202 can be any type of processor capable of providing
19. the appropriate server the server may send the requested web page to the load balancer The load bal ancer may then send the web page to the client computer where the browser may display the web page for the user A problem may occur if there is an unreasonable delay in accessing the web page The user may get impatient and cancel the request only to submit another request for the same web page immediately thereafter The cancellation may result in the termination of the connection between the client computer and the load balancer and also the connection between the load balancer and the server Once the user sub mits the other request both connections will have to be re established prior to retrieving the requested information This may lead to the inefficient use of network resources To avoid this and other potential problems one embodi ment of the user maintains the connection between the load balancer and the server despite the cancellation of the con nection between the client computer and the load balancer Once the load balancer receives the requested information the load balancer may store the requested information with the source address of the client computer and the information address of the information e g the URL in an information table If the client computer attempts to establish a new con nection requesting the same information the load balancer may retrieve the information from the information table and send it t
20. the speed and functionality required by the embodiments of the invention For example processor 202 could be a processor from family of processors made by Intel Corporation Motorola Incorporated Sun Microsystems Incorporated Compaq Computer Corporation and others Processor 202 may also comprise a digital signal processor DSP and accompanying architecture such as a DSP from Texas Instruments Incorporated In one embodiment ofthe invention memory 210 and disk storage 218 may comprise a machine readable medium and may include any medium capable of storing instructions adapted to be executed by a processor Some examples of such media include but are not limited to read only memory ROM random access memory RAM programmable ROM erasable programmable ROM electronically erasable programmable ROM dynamic RAM magnetic disk eg floppy disk and hard drive optical disk e g CD ROM and any other media that may store digital information In one embodiment of the invention the instructions are stored on the medium in a compressed and or encrypted format As ja 5 20 25 35 40 45 55 65 4 used herein the phrase adapted to be executed by a proces sor is meant to encompass instructions stored in a com pressed and or encrypted format as well as instructions that have to be compiled or installed by an installer before being executed by the processor Further client 200 may contain various combinations of
21. the web switch and the server Once the web switch has sent the web page to the client computer the web page may delete the web page and corre sponding entries from its information table Alternatively the web switch may maintain the information similar to a caching appliance and delete it after a certain time has passed for example In this example the web switch may associate an aging timer with the source address URL and information and may delete certain entries at periodic or predetermined intervals This may be implemented to avoid exceeding memory thresholds or keeping invalid information In one embodiment of the invention the web switch may use a first in first out FIFO concept where the oldest stored information may be deleted if maximum memory usage is reached In one embodiment of the invention the servers may not use the source IP address to send the requested information This may occur for example in a network using network address translation NAT technology In this embodiment of the invention it may not be necessary for the web switch to store the source IP address together with the URL in its information table While certain features of the embodiments of the invention have been illustrated as described herein many modifica tions substitutions changes and equivalents will now occur to those skilled in the art It is therefore to be understood that the appended claims are intended to cover all such modific
22. with an artificial client or by sending it a series of scripts that can try out critical pages and look at the responses for example A user may typically attempt to access information on a server using a browser located on a client computer such as a personal computer PC The information may comprise for example a web page The user may initiate the action by typing in an information identifier for the web page An example of an information identifier may be a uniform resource locator URL The browser may then use the URL to attempt to establish a connection between the client com puter and the server where the web page is stored using a conventional network protocol An example of such a proto col may include the Hypertext Transfer Protocol HTTP Version 1 1 as defined by the Internet Engineering Task Force IETF Draft Standard Request For Comment RFC 2616 June 1999 and available from www ietf org HTTP Specification although the embodiments of the invention are not limited in this context The network access device such as a load balancer may intercept and process the connection request on behalf ofthe server If the requested web page resides on more than one server in the network the load balancer may select a particu lar server based on various parameters such as those dis cussed above The load balancer may then attempt to establish a connection with the selected server Once a connection is established with
23. y b ACK ER SYN q SYN ACK ACK REO header ACK REQ2 h adetebody Fl p ACK EI 3 R amp Q3 body d ACK lt RESP heads ACK SYN SYN ACK ACK REGQ1 header o ACK REQ2 headerebody b CS q RESP2 headsrebod ACK ACK o RESP header ACK t RESP2 headerebod RESP3Ibody ACK d RESP4 body RESPA body ACK ACK Fi D o fi e ACK FI ACN EI tima ume US 7 899 911 B2 US 7 899 911 B2 1 METHOD AND APPARATUS TO RETRIEVE INFORMATION IN A NETWORK BACKGROUND A network typically comprises a plurality of network nodes connected together by a communications medium A network node may comprise for example a switch router personal computer server network appliance or any other network device A network node such as a server may store information in the form of files created in accordance with various formats such as a hypertext markup language HTML file extensible markup language XML file and so forth A file may also be referred to as a page or web page Whenever a user may desire a particular file the user may request access to the file using a number of network protocols A protocol may be a predetermined process by which infor mation is exchanged between network nodes Due to the high performance demands of certain applica tions it may become necessary to implement technology to ensure that a user may access a desired file with a high level of confidence and reduced latency To accomplish this t
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