Cache validation using rejuvenation in a data network

• US 20030188106A1
• Filed: 04/12/2002
• Published: 10/02/2003
• Est. Priority Date: 03/26/2002
• Status: Abandoned Application

• Current Assignee: AT&T Properties, LLC (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Cohen, Edith
• Application Number:
  US10/063,343
• Publication Number:
  US 20030188106A1
• Time in Patent Office: Days
• US Class Current: 711/133
• 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 at a non-authoritative source serving at least one client cache, the method comprising:

(a) determining whether the content has a freshness metric below a threshold value; and

(b) sending a validation request to an authoritative server to refresh the content when the content has a freshness metric below the threshold value.

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

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

3. The method of claim 1 wherein the freshness metric for the content is a time-to-live value.

4. The method of claim 3 wherein the threshold value is a fraction υ

of an original time-to-live value, where υ

<

1.

5. The method of claim 4 wherein υ

is chosen such that 1/υ

is an integer value.

6. The method of claim 1 wherein the validation request is sent in synchronization with requests directed to the non-authoritative source.

7. The method of claim 1 wherein the non-authoritative source is a high-level cache in a caching hierarchy.

8. The method of claim 1 wherein the non-authoritative source is a reverse proxy server.

9. The method of claim 1 wherein the content is validated using the Hyper Text Transfer Protocol (HTTP).

10. A method of validating content at a non-authoritative source serving at least one client-cache, the method comprising:

(a) receiving a request for content from the client-cache;

(b) determining whether a copy of the content stored at the non-authoritative source has a freshness metric below a threshold value; and

(c) when the content has a freshness metric below the threshold value, sending a validation request to an authoritative server to refresh the content while responding to the request for content with the copy of the content stored at the non-authoritative source.

11. The method of claim 10 further comprising the step of:

(d) updating the freshness metric for the content based on a response from the authoritative server where the copy of the content at the authoritative server has not been modified.

12. The method of claim 10 wherein the freshness metric for the content is a time-to-live value.

13. The method of claim 12 wherein the threshold value is a fraction υ

of an original time-to-live value, where υ

<

1.

14. The method of claim 13 wherein υ

is chosen such that 1/υ

is an integer value.

15. The method of claim 10 wherein the validation request is sent in synchronization with requests directed to the non-authoritative source.

16. The method of claim 10 wherein the non-authoritative source is a high-level cache and the client-cache is a low-level cache in a caching hierarchy.

17. The method of claim 10 wherein the non-authoritative source is a reverse proxy server.

18. The method of claim 10 wherein the content is validated using the Hyper Text Transfer Protocol (HTTP).

19. A device-readable medium storing program instructions for performing a method of validating content at a non-authoritative source serving at least one client cache, the method comprising the steps of:

(a) determining whether the content has a freshness metric below a threshold value; and

(b) sending a validation request to an authoritative server to refresh the content when the content has a freshness metric below the threshold value.

20. The device-readable medium of claim 19 further comprising the step of:

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

21. The device-readable medium of claim 19 wherein the freshness metric for the content is a time-to-live value.

22. The device-readable medium of claim 21 wherein the threshold value is a fraction υ

of an original time-to-live value, where υ

<

1.

23. The device-readable medium of claim 22 wherein υ

is chosen such that 1/υ

is an integer value.

24. The device-readable medium of claim 19 wherein the validation request is sent in synchronization with requests directed to the non-authoritative source.

25. The device-readable medium of claim 19 wherein the non-authoritative source is a high-level cache in a caching hierarchy.

26. The device-readable medium of claim 19 wherein the non-authoritative source is a reverse proxy server.

27. The device-readable medium of claim 19 wherein the content is validated using the Hyper Text Transfer Protocol (HTTP).

28. A device-readable medium storing program instructions for performing a method of validating content at a non-authoritative source serving at least one client cache, the method comprising the steps of:

(a) receiving a request for content from the client-cache;

(b) determining whether a copy of the content stored at the non-authoritative source has a freshness metric below a threshold value; and

(c) when the content has a freshness metric below the threshold value, sending a validation request to an authoritative server to refresh the content while responding to the request for content with the copy of the content stored at the non-authoritative source.

29. The device-readable medium of claim 28 further comprising the step of:

(d) updating the freshness metric for the content based on a response from the authoritative server where the copy of the content at the authoritative server has not been modified.

30. The device-readable medium of claim 28 wherein the freshness metric for the content is a time-to-live value.

31. The device-readable medium of claim 30 wherein the threshold value is a fraction υ

of an original time-to-live value, where υ

<

1.

32. The device-readable medium of claim 31 wherein υ

is chosen such that 1/υ

is an integer value.

33. The device-readable medium of claim 28 wherein the validation request is sent in synchronization with requests directed to the non-authoritative source.

34. The device-readable medium of claim 28 wherein the non-authoritative source is a high-level cache and the client-cache is a low-level cache in a caching hierarchy.

35. The device-readable medium of claim 28 wherein the non-authoritative source is a reverse proxy server.

36. The device-readable medium of claim 28 wherein the content is validated using the Hyper Text Transfer Protocol (HTTP).