Method and apparatus for content synchronization

• US 8,756,342 B1
• Filed: 06/08/2000
• Issued: 06/17/2014
• Est. Priority Date: 02/07/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Corporation
• Original Assignee: Parallel Networks, LLC (epicRealm Licensing LP)
• Inventors: Lowery, Keith A., Davidson, David K., Saxena, Avinash C.
• Primary Examiner(s): SHINGLES, KRISTIE D
• Application Number:
  US09/590,760
• Time in Patent Office: 5,122 Days
• Field of Search: 709/217, 709/203, 709/219, 709/248, 709/206, 709/207, 709/226, 709/223, 709/246, 707/10
• US Class Current: 709/246
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: G06F 16/958 Organisation or management of web site content, e.g. publishing, maintaining pages or automatic linking
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A data center (14) receives a request (22) for content from a browser (12) on a client (11). The data center determines whether the requested content is available at the data center. The content is available when the content is both present at the data center and current. The content may be expired and marked as non-available in response to an expiration command (24). When the requested content is available at the data center, the data center returns the requested content to the data center. When the requested content is locally unavailable at the data center, the requested content is retrieved from an origin server (18). The retrieval of the content from the origin server may be delayed based on the processing load at the origin server. When retrieval of the content is delayed, the request is prioritized and placed in a queue for handling by the origin server based on the priority of the request. Also, when retrieval of the content is delayed, a status page may be communicated to the browser to inform a user of the delay and provide alternate content (139) and status information related to the request determined as a function of the request or the current state of the origin server.

Claims

1. A method for processing data comprising:

storing a data item at a cache server, the data item being accessed by a data request from a remote computer, the data item stored at the cache server being based on underlying content maintained at a data source, the data request including a uniform resource locator associated with the data item;

receiving at a data center manager a data change message from a trigger associated with the data source, the data change message generated in response to a change in the underlying content at the data source for the data item;

generating an expiration command at the data center manager in response to the data change message;

receiving the expiration command at the cache server from the data center manager; and

marking the data item at the cache server as expired according to the expiration command;

controlling, by a flow control server, retrieval by the cache server of the data item from an origin server, wherein controlling retrieval comprises;

determining at the flow control server a current load associated with the origin server;

prioritizing at the flow control server the data item; and

determining when the cache server retrieves the data item based on the current load of the origin server and the priority of the data item.

2. The method for processing data according to claim 1 further comprising:

receiving a data request at the cache server from remote computer, the data request requesting the data item from the cache server;

determining whether the data item is available at the cache server;

retrieving the data item from the origin server when the data item is unavailable at the cache server, the origin server retrieving the underlying content from the data source to produce the data item; and

communicating the data item from the cache server to the remote computer.

3. The method for processing data according to claim 2 wherein the data item comprises a web page and further comprising generating the web page at the origin server.

4. The method for processing data according to claim 3, wherein generating the web page comprises generating the web page based on the data request.

5. The method for processing data according to claim 2, wherein determining whether the data item is available comprises:

determining whether the data item is present at the cache server; and

determining whether the data item is current when the data item is present at the cache server.

6. The method for processing data according to claim 1, wherein determining when the cache server retrieves the data item comprises:

granting permission to the cache server when the current load of the origin server is below a predetermined threshold; and

denying permission to the cache server when the current load of the origin server exceeds the predetermined threshold.

7. The method for processing data according to claim 1 further comprising generating the expiration command at the data center manager in response to the elapsing of a predetermined period of time.

8. The method for processing data according to claim 1, wherein generating the expiration command comprises:

detecting a change in the underlying content at the data source by a trigger associated with the underlying content;

generating the data change message indicating at least one change in the underlying content; and

communicating the data change message to the data center manager.

9. The method for processing data according to claim 1, wherein marking the data as expired comprises receiving the expiration command from the data center manager and determining the data item to expire as a function of the expiration command.

10. The method for processing data according to claim 9, wherein the expiration command expires a single web page.

11. The method for processing data according to claim 9, wherein the expiration command expires a plurality of web pages.

12. The method for processing data according to claim 9, wherein the expiration command expires a plurality of web pages at a plurality of web sites.

13. The method for processing data according to claim 9, wherein the expiration command expires a plurality of web pages at a plurality of domains.

14. The method for processing data according to claim 1, wherein the data item comprises a web page using the hypertext markup language.

15. The method for processing data according to claim 1, wherein the expiration command comprises an Internet Cache Synchronization Protocol command.

16. The method for processing data according to claim 15, wherein the expiration command comprises an Internet Cache Synchronization Protocol terse command and further including generating the expiration command at the data center manager in response to an Internet Cache Synchronization Protocol verbose command.

17. The method for processing data according to claim 1, wherein the data item has an associated request element identifying the data item, the request element having a first portion and a second portion distinct from the first portion and wherein the data item is accessed at the cache server by:

filtering the first portion of the request element based on predetermined criteria associated with an origin server associated with the data item; and

identifying the data item based on the second portion of the request element.

18. The method for processing data according to claim 17 further comprising:

receiving a data request at the cache server, a first portion of the data request being distinct from the first portion of the request element and a second portion of the data request being substantially similar to the second portion of the request element; and

retrieving the data item as a function of the second portion of the data request and the second portion of the request element.

19. The method for processing data according to claim 18, wherein the request element comprises a uniform resource locator and the data request comprises a uniform resource locator.

20. A method for providing efficient data access service comprising:

subscribing an origin server to a data center;

routing a data request from a browser to the data center, the data request requesting a dynamic content item and having an associated address indicating the origin server, the data request including a uniform resource locator associated with the dynamic content item;

receiving at a data center manager, before expiration of the dynamic content item, a data change message from a trigger at a data source associated with the dynamic content item, the data change message generated in response to a change in the underlying content for the dynamic content item maintained at the data source;

generating an expiration command at the data center manager in response to the data change message;

receiving the expiration command from the data center manager;

updating an expiration time of the dynamic content item in accordance with the expiration command;

determining whether the dynamic content item is available at the data center according to the expiration time of the dynamic content item;

generating the dynamic content item at the origin server from the underlying content at the data source when the dynamic content item is unavailable at the data center;

retrieving the dynamic content item from the origin server when the dynamic content item is unavailable at the data center; and

communicating the dynamic content item to the browser;

controlling, by a flow control server, retrieval of the data item from the origin server, wherein controlling retrieval comprises;

determining at the flow control server a current load associated with the origin server;

prioritizing at the flow control server the data item; and

determining when the data item is retrieved based on the current load of the origin server and the priority of the data item.

21. The method for providing efficient data access service according to claim 20, wherein subscribing the origin server comprises transferring domain name resolution service to the data center and wherein routing the data request comprises resolving the address associated with the origin server.

22. The method for providing efficient data access service according to claim 20, wherein determining whether the dynamic content item is available comprises:

determining whether the dynamic content item is present at the data center; and

determining whether the dynamic content item is current when the dynamic content item is present at the data center.

23. A system for processing data comprising:

a data center operable to receive a request from a client;

a data source operable to maintain underlying content for data items cached at the data center; and

a data center manager coupled to the data source and the data center, the data source operable to generate a data change message in response to a change in the underlying content maintained at the data source for a particular data item cached at the data center, the particular data item being accessed by a data request from a remote computer, the data request including a uniform resource locator associated with the particular data item, and the data center manager operable to receive the data change message and generate an expiration message in response to the data change message indicating an expiration of the particular data item, the data center manager operable to send the expiration message to the data center;

wherein the data center is operable to control retrieval of the particular data item by;

determining a current load associated with an origin server;

prioritizing the particular data item; and

determining when the particular data item is retrieved based on the current load of the origin server and the priority of the data item.

24. The system for processing data according to claim 23, wherein the data center comprises a web server, a cache server and a flow control server, the flow control server operable to control retrieval of the particular data item.

25. The system for processing data according to claim 24, wherein the web server is operable to receive the request from the client, wherein the cache server is operable to cache data items, and wherein the flow control server is operable to prioritize the request and control access to an to the origin server and the data source for the cache server for retrieval of data items not cached at the cache server.