Cache validation using smart source selection in a data network

• US 20030187917A1
• Filed: 04/12/2002
• Published: 10/02/2003
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property II LP (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Cohen, Edith
• Granted Patent: US 8,650,266 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• 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 67/5682 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

In accordance with aspects of the invention, “low-level” caches can utilize source selection while non-authoritative sources can take advantage of rejuvenation to alleviate what the inventor refers to as “age penalty” and thereby reduce validation traffic.

Claims

1. A method of validating content in a cache comprising:

(a) selecting a source server based at least in part on expected remaining freshness of a copy of the content retrieved from the source server; and

(b) sending a validation request to the selected source server.

2. The method of claim 1 further comprising the step of:

(c) updating freshness of the content based on a response from the selected source server where the copy of the content at the selected source server has not been modified.

3. The method of claim 1 wherein the source server is selected from a group consisting of authoritative servers and replicated content servers.

4. The method of claim 3 wherein the replicated content servers are high-level cache servers.

5. The method of claim 3 wherein the replicated content servers are reverse proxy servers.

6. The method of claim 1 wherein the source server is selected based at least in part on an estimate of fetching time to the source server and on likelihood of a cache miss at the source server.

7. The method of claim 1 wherein freshness of the content is measured by a time-to-live value.

8. The method of claim 7 wherein content is validated using the Hyper Text Transfer Protocol (HTTP).

9. A device-readable medium storing program instructions for performing a method of validating content in a cache, the method comprising the steps of:

(a) selecting a source server based at least in part on expected remaining freshness of a copy of the content retrieved from the source server; and

(b) sending a validation request to the selected source server.

10. The device-readable medium of claim 9 further comprising the step of:

(c) updating freshness of the content based on a response from the selected source server where the copy of the content at the selected source server has not been modified.

11. The device-readable medium of claim 9 wherein the source server is selected from a group consisting of authoritative servers and replicated content servers.

12. The device-readable medium of claim 11 wherein the replicated content servers are high-level cache servers.

13. The device-readable medium of claim 11 wherein the replicated content servers are reverse proxy servers.

14. The device-readable medium of claim 9 wherein the source server is selected based at least in part on an estimate of fetching time to the source server and on likelihood of a cache miss at the source server.

15. The device-readable medium of claim 9 wherein freshness of the content is measured by a time-to-live value.

16. The device-readable medium of claim 15 wherein content is validated using the Hyper Text Transfer Protocol (HTTP).