Method and apparatus for improving end to end performance of a data network

• US 20040254921A1
• Filed: 04/13/2004
• Published: 12/16/2004
• Est. Priority Date: 06/26/1998
• Status: Active Grant

• Current Assignee: Balachander Krishnamurthy, Edith Cohen, Jennifer Lynn Rexford
• Original Assignee: Balachander Krishnamurthy, Edith Cohen, Jennifer Lynn Rexford
• Inventors: Krishnamurthy, Balachander, Rexford, Jennifer Lynn, Cohen, Edith
• Granted Patent: US 7,657,553 B2
• Time in Patent Office: Days
• US Class Current: 707/3
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A method and apparatus provide improved cache coherency and more effective caching operations without placing an undue burden on network links. A proxy receives a request for a resource and then, depending on information in the proxy cache, generates a resource request for transmission to a resource server. The proxy appends a proxy filter to the request. The resource server maintains one or more volumes of resources based on some predetermined criterion that can be either static or dynamic in nature. Upon receipt of the request and the proxy filter the resource server generates a request response and a piggybacked list of additional resources selected from the volume with which the requested resource is associated.

Claims

1-13. -13. (Cancel)

14. A method for effecting a transfer of information to a proxy server, said proxy server having a cache storing a plurality of resources, the method performed at a resource server, the method comprising the steps of:

receiving a request from a proxy server, wherein the request seeks information about a particular resource;

retrieving information regarding said particular resource in response to said request;

examining a volume of resource information with which said particular resource is associated, said volume also including information relating to resources other than said particular resource;

compiling information from a subset of said volume of resource information; and

generating a response to the received request using the retrieved information and the compiled information.

15. The method of claim 14 comprising the further step of,

receive a proxy filter with said request from said proxy server, and

wherein said step of compiling information comprises compiling information based, at least in part, on said proxy filter.

16. The method of claim 14 wherein the retrieved information includes a copy of the particular resource.

17. The method of claim 14 wherein the retrieved information includes an indication of when the requested particular resource was last modified.

18. The method of claim 14 wherein the compiled information includes an identifier for said at least one further resource.

19. The method of claim 18 wherein said compiled information includes attribute information regarding said at least one further resource.

20. A method for facilitating proxy server cache updates, the method performed at a resource server, the method comprising the steps of

receiving a request for information regarding a first resource;

receiving a proxy filter associated with a proxy server associated with the received request;

retrieving information responsive to said request;

analyzing a volume of resources related to said first resource using said received proxy filter so as to identify at least a second resource of potential interest to said proxy server;

identifying attribute information regarding said at least a second resource;

generating a response to said request based on the retrieved information and the identified attribute information; and

transmitting the response to the proxy server associated with the received request.

21. The method of claim 20 wherein said proxy filter includes a selection parameter for choosing one or more resources from a volume of resources related to said first resource.

22. The method of claim 21 wherein said selection parameter is selected from a group of resource attributes that includes, resource size, resource content type, a resource change rate and a resource request frequency.

23. The method of claim 20 wherein said request for information includes an identifier for said first resource and information available at said proxy server regarding a last modification time of said first resource.

24. The method of claim 23 wherein said step of retrieving information includes retrieving a last modification time for said first resource.

25. The method of claim 24 wherein said step of retrieving information includes the further substeps of:

comparing the retrieved last modification time and said information regarding a last modification time included in said request; and

retrieving another copy of said first resource when said step of comparing indicates that said modification time for said first resource at said resource server differs from said last modification time for said first resource included in said request.

26. The method of claim 25 wherein said step of generating a response includes the step of combining said another copy of said first resource with the identified attribute information.

27. The method of claim 26 wherein said proxy filter includes a selection parameter for choosing one or more resources from a volume of resources related to said first resource.

28. The method of claim 27 wherein said selection parameter is selected from a group of resources attributes that includes, resource size, resource content type, a resource change rate and a resource request frequency.

30. The method of claim 28 wherein the volume includes information regarding associated resources.

31. The method of claim 30 wherein said information includes an identifier for each resource.

32. The method of claim 31 wherein said information includes a size of each resource.

33. The method of claim 30 wherein said information includes an identifier for each resource and information about when each resource was last modified.

29. A method for creating a volume of resources from a plurality of resources available to a resource server, the method performed at said resource server, the method comprising the steps of:

detecting when a first resource is requested of the resource server;

identifying a second resource that is requested from said resource server within a time period following the request for the first resource;

determining a probability that said resource will also be requested if said first resource is requested; and

if said probability satisfies a minimum threshold then associating said first resource and said second resource in a volume.

47. The method of claim 29, wherein the probability is determined only if the first resource and the second resource each have a same directory prefix.

34. A method for creating a volume of resources from a plurality of resources available to a server, each of said plurality of resources having an associated directory prefix, the method performed at said server, the method comprising the steps of:

analyzing the directory prefix of each of a said plurality of resources;

dividing the resources into a plurality of subsets based on matching directory prefixes of the resources to a predetermined prefix level;

associating resources in at least one of said plurality of subsets in a respective volume, wherein each said volume includes an identifier for each resource associated with the respective volume.

35. The method of claim 34 wherein each said volume further includes information

about the size of each resource included therein.

36. The method of claim 34 wherein each said volume further includes information about when each resource included therein was last modified.

37. A method for providing a proxy server with supplemental information in response to a request related to a resource available to a server, the method performed at said server the method comprising the steps of

creating a volume center, wherein a plurality of volumes are stored, each volume including information about related resources;

receiving a request from said proxy server referring to one of the volumes at said volume center; and

sending volume information related to said request to the requesting proxy server.

38. The method of claim 37 wherein said volume information includes identifiers for a plurality of related resources and information regarding when each said related resource was last modified.

39. The method of claim 38 comprising the further steps of:

receiving a request to send the resource to the requesting server if the information in the volume information about when the requested resource was last modified does not satisfy a predetermined criterion;

piggybacking the volume information to a resource returned in response to the request to send the resource; and

forwarding the resource and piggybacked volume information to the proxy server that issued the request related to the resource.

40. The method of claim 37 comprising the further steps of,

receiving a proxy filter sent by the proxy server along with the resource request;

and

selecting a subset of information from a volume related to the resource associated with the resource request, wherein said step of forwarding forwards the selected subset.

41-42. -42. (cancel)

43. A method for improving cache operations of a proxy server, the method performed at said proxy server, the method comprising the steps of:

receiving a response to a request related to a resource, wherein said response includes information about resources related to the resource associated with the request;

analyzing said information to determine if said information indicates that any resources stored in said cache have been modified; and

if said step of analyzing indicates that at least one resource has been modified, updating at least one of said modified resources.

44. The method of claim 43 wherein said step of updating includes requesting the modified version of at least one of said modified resources.

45. The method of claim 43 wherein said step of updating includes initiating a request for differences between the version of the resource stored in the cache and the modified version of the resource.

46. A method for improving cache operations of a proxy server, the method performed at a proxy server having a cache, the method comprising the steps of:

receiving a response to a request related to a resource, wherein said response includes information about resources related to the resource associated with the request;

analyzing said information to determine if said information indicates that any resource referred to in said information is not stored at said cache; and

in response to the step of analyzing, fetching a resource not stored in said cache.