METHOD AND APPARATUS FOR ACCELERATION BY PREFETCHING ASSOCIATED OBJECTS

• US 20080222244A1
• Filed: 03/07/2008
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Riverbed Technology, LLC (Riverbed Technology Incorporated)
• Original Assignee: Riverbed Technology Incorporated
• Inventors: Gupta, Nitin, Keswani, Vivasvat, Huang, Charles, Robinson, Bart
• Granted Patent: US 8,533,310 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54

Abstract

Association information is used to build association trees to associate base pages and embedded objects at a proxy. An association tree has a root node containing a URL for a base page, and zero or more leaf nodes each containing a URL for an embedded object. In most cases, an association tree will maintain the invariant that all leaves contain distinct URLs. However, it is also possible to have an association tree in which the same URL appears in multiple nodes. An association tree may optionally contain one or more internal nodes, each of which contains a URL that is an embedded object for some other base page, but which may also be fetched as a base page itself. Given a number of association trees and a base-page URL, a prefetch system finds the root or interior node corresponding to that URL (if any) and traverses the tree from that node, prefetching URLs until the URL of the last leaf node is prefetched. The prefetching starts the process of bringing over the various embedded objects before the user or program would ordinarily fetch them.

Claims

1. A method of accelerating client-server transactions at a proxy, the method comprising:

intercepting an initial request from a client;

forwarding the initial request to an origin server;

receiving a response from the origin server;

recording the initial request as a root node;

outputting the response to the client;

intercepting subsequent requests from the client;

identifying a first subsequent client'"'"'s request associated with the initial request;

constructing an associate tree having the root node and at least one leaf node which is coupled to that root node; and

prefetching the at least one leaf node.

2. The method of claim 1, wherein recording the initial request comprises successfully receiving a response from the origin server;

3. The method of claim 1, wherein outputting the response comprises inserting a tag in the response.

4. The method of claim 3, wherein the tag comprises a string of N characters, with N being an integer value including zero.

5. The method of claim 1, wherein identifying a first subsequent client'"'"'s request further comprises:

parsing (examining) an attribute embedded in a HTTP header;

comparing the attribute with a portion of the recorded initial request; and

obtaining a match.

6. The method of claim 1, wherein the at least one leaf node is the identified first subsequent client'"'"'s request.

7. A method of associating embedded objects with base pages at a proxy, the method comprising:

classifying a request as base page or as an embedded object;

detecting a containment attribute on a request for an embedded object;

extracting a base page identification from the containment attribute;

grouping the embedded object with the base page identified in the extracting step; and

marking a response with zero or more distinctive tags representing a grouping from the grouping step.

8. The method of claim 7, wherein classifying a request comprises distinguishing a request by the structure or content of the request, such as by suffix, prefix, or contained substring.

9. The method of claim 7, wherein detecting a containment attribute comprises finding an HTTP Referrer header.

10. The method of claim 7, wherein detecting a containment attribute comprises finding an HTTP Cookie field with a value generated by the proxy.

11. The method of claim 7, wherein extracting the base page identification comprises reading a URL or other identifier from a particular header of the request.

12. The method of claim 7, wherein extracting the base page identification comprises reading a key from a particular header of the request and finding an associated URL value from a key-value data structure.

13. The method of claim 7, wherein grouping the embedded object comprises building a tree data structure where the base page is at the root node and the embedded object is at least one leaf node.

14. The method of claim 7, wherein marking a response comprises setting an HTTP cookie with a distinct value that is recognizable in subsequent interactions.

15. A proxy interposed between at least one client and at least one server for accelerating client-server transactions, the proxy comprising:

a processor including memory modules and mass storage units;

program instructions for intercepting requests issued from a client, classifying the requests, recording a base page (base URL), constructing an associate tree having one or more root nodes; and

program instructions for prefetching objects based on the constructed associate tree.

16. The proxy of claim 15, wherein the classifying the requests comprises distinguishing the requests based on the structure of their prefixes, suffixes, or contained substrings.

17. The proxy of claim 15, wherein recording the base page further comprises:

receiving a successful response from an origin server, wherein the successful response corresponds to an initial request;

adding a tag to the successfully received response; and

outputting the response with the added tag to the client.

18. The proxy of claim 17, wherein the initial request is a root node of the associate tree.

19. The proxy of claim 18, wherein the root node comprises at least one leaf node.

20. The proxy of claim 19, wherein the at least one leaf node is a subsequent request associated with the initial request.

21. The proxy of claim 17, wherein the tag comprises a string of N characters.

22. The proxy of claim 21, wherein N is an integer value including zero.

23. The proxy of claim 15, wherein the prefetched objects are stored in the memory units or mass storage units.