Peer server handoff in content delivery network

• US 20080065724A1
• Filed: 10/30/2007
• Published: 03/13/2008
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Digital Impact Incorporated (Liberty Latin America Ltd.), Level 3 Communications LLC (Lumen Technologies, Inc.)
• Original Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Inventors: HOBBS, Kevin, FORAKER, Isaac, GLYNN, Shane, JONES, Peter, CHEN, Homer, SEED, Steven
• Granted Patent: US 8,924,466 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/2885 Hierarchically arranged intermediate devices, e.g. for hierarchical caching
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• 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

Abstract

A content delivery method directs a request by a client for an object to a first server in a content delivery network (CDN), regardless of whether the first server has the requested object. If the first server has the requested object, then it is served to the client from the first server; otherwise, the first server redirects the client request to a second server in the CDN to handle the request. The second server may be a peer server of the first server. The first and second servers may be edge servers in the CDN.

Claims

1. A content delivery method comprising:

directing a request by a client for an object to a first server in a content delivery network (CDN), regardless of whether the first server has the requested object;

if the first server has the requested object, serving the requested object to the client from the first server;

otherwise, redirecting the client to a second server in the CDN to handle the request.

2. A method as recited in claim 1, wherein the first server in the CDN is an edge server.

3. A method as recited in claim 2, further comprising:

receiving, at the second server, a second request for the object from the client; and

responsive to said second request, serving the requested object to the client from the second server.

4. A method as recited in claim 1, wherein the second server in the CDN is a parent server.

5. A method as recited in claim 1, wherein the second server is a peer of the first server.

6. A method as recited in claim 1, wherein the first server in the CDN is an edge server and the second server is an edge server on which a copy of the requested object is stored.

7. A method as recited in claim 5, further comprising:

receiving, at the second server, a second request for the object from the client; and

serving the requested object to the client from the second server.

8. A method as recited in claim 1, wherein the object is a streaming object.

9. A method as recited in claim 1, wherein said first server was selected based at least in part on network traffic conditions and server load.

10. A method as recited in claim 1, further comprising:

attempting to serve the requested object to the client from the second server in the CDN.

11. A method as recited in claim 1, wherein if a copy of the requested object is not stored on the second server, directing the client to another server in the CDN.

12. A method as recited in claim 11, wherein the step of directing is repeated for a plurality of other servers in the CDN.

13. A method, in a framework in which resources of content providers are delivered to end user clients via a shared content delivery network (CDN) formed of a plurality of CDN server sites, each server site comprising one or more servers, the method comprising:

causing a client request for a resource to be directed to a first server site in said CDN, without consideration as to whether the first server site has a copy of the requested resource;

if the first server site has a copy of the requested resource, then serving the requested resource to the client from the first server site;

otherwise,

if the first server site does not have a copy of the requested resource, causing the client to be directed to a second server site in the CDN.

14. A method as recited in claim 13, further comprising:

attempting to serve the requested resource to the client from the second server site in the CDN.

15. A method as recited in claim 13, wherein the CDN sites comprise one or more edge server sites, each edge server site comprising one or more edge servers, and wherein the first server site is an edge server site.

16. A method as recited in claim 15, wherein the second server site is another edge server site.

17. A method as recited in claim 13, wherein the second server site is a peer of the first server site.

18. A method as recited in claim 15, wherein the CDN sites further comprise one or more parent server sites, each parent server site comprising one or more parent servers, and wherein the second server site is a parent server site or an edge server site.

19. A method as recited in claim 13, wherein a copy of the requested resource is stored at the second server site prior to the issuance of the resource request by the client.

20. A method, in a framework in which resources of at least one content provider are delivered to end user clients via a content delivery network (CDN) formed of a plurality of CDN server sites, each server site comprising one or more servers, the method comprising:

receiving a client request for a resource at a first server site in said CDN;

if the first server site has a copy of the requested resource, then serving the requested resource to the client from the first server site;

otherwise,

if the first server site does not have a copy of the requested resource, then causing the client to retrieve the requested resource from a second server site in the CDN.

21. A method as recited in claim 20, wherein the CDN server sites comprise a plurality of edge server sites, each edge server site comprising at least one edge server, and wherein the first server site is a edge server site.

22. A method as recited in claim 20, wherein the second server site is another edge server site.

23. A method as recited in claim 20, wherein the second server site is a peer of the first server site.

24. A method as recited in claim 22, wherein the CDN server sites further comprise a plurality of parent server sites, each parent server site comprising at least one parent server, and wherein the second server site is a parent server site in the CDN.

25. A method as recited in claim 21, a copy of the requested resource is stored at the second server site prior to receipt of the client request by the first server site.