Delivering resources to clients in a distributed computing environment with rendezvous based on load balancing and network conditions

• US 20080215755A1
• Filed: 10/31/2007
• Published: 09/04/2008
• Est. Priority Date: 02/10/1998
• Status: Active Grant

• Current Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Original Assignee: Level 3 Communications LLC (Lumen Technologies, Inc.)
• Inventors: Greer, Richard E., Farber, David A., Swart, Andrew D., Balter, James A.
• Granted Patent: US 8,296,396 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: G06F 16/957 Browsing optimisation, e.g. caching or content distillation
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1006 with static server selection, e.g. the same server being selected for a specific client
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1019 Random or heuristic server selection
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1025 Dynamic adaptation of the criteria on which the server selection is based
• 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 67/2895 Intermediate processing functionally located close to the data provider application, e.g. reverse proxies
• CPC Class Codes: H04L 67/561 Adding application-functional data or data for application control, e.g. adding metadata
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A plurality of repeater servers form a shared content delivery network (CDN) to serve resources to clients on behalf of a plurality of content providers. First and second resources are associated with a first content provider, the first resource referencing the second resource. The second resource is associated with a domain of the shared CDN. Responsive to a request that causes the first resource to be served to a client from a server in a domain associated with the first content provider, a CDN server is identified in the domain associated with the shared CDN to serve the second resource to the client. The CDN server is selected based, at least in part, on load conditions on at least some of the CDN servers, and on the client'"'"'s location. Responsive to the CDN server being requested to serve the second resource: if a copy of the second resource is available on the CDN server, the copy is served to the client from the CDN server; otherwise, the second resource is replicated on the CDN server and then served to the client from the CDN server.

Claims

1. A method for delivering resources to clients in a framework in which a plurality of repeater servers form a shared content delivery network (CDN) operable to serve resources to clients on behalf of a plurality of content providers, wherein a first resource is associated with a first content provider, and wherein said first resource references a second resource, the method comprising:

(A) associating the second resource with a domain of said shared CDN; and

(B) responsive to a request that causes the first resource to be served to a client from content source distinct from said plurality of repeater servers, identifying a repeater server in the domain of said shared CDN to serve the second resource to the client, said repeater server having been selected based, at least in part, on a relative location corresponding to said client and at least some of the plurality of repeater servers; and

(C) responsive to the identified repeater server being requested to serve the second resource;

(c1) if a copy of the second resource is available on the identified repeater server, serving the copy of the second resource to the client from the identified repeater server;

otherwise,

(c2) if a copy of the second resource is not available on the identified repeater server,

(c21) replicating the second resource on the identified repeater server, and

(c22) serving the replicated second resource to the client from the identified repeater server.

2. A method as recited in claim 1, wherein the first resource references the second resource via a uniform resource locator (URL) having a name associated with said first content provider, and wherein the associating step (A) comprises:

modifying the URL to include data identifying the domain of said shared CDN.

3. A method as recited in claim 2, wherein the modifying step comprises:

prepending the data to at least the name associated with the first content provider.

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

further responsive to the request that causes the first resource to be served to the client, transmitting an HTTP REDIRECT command comprising the modified first URL to the client.

5. A method as recited in claim 2, wherein the URL is a textual reference embedded in the first resource.

6. A method as recited in claim 1, wherein the identified repeater server is selected, at least in part, by a software component co-located with a server in a domain associated with said first content provider, said domain associated with said first content provider being at least partially distinct from the domain of the shared CDN.

7. A method as recited in claim 1, wherein, further responsive to the request that causes the first resource to be served to the client, the client is provided an address corresponding to the identified repeater server.

8. A method as in claim 1, wherein the first resource references the second resource using a uniform resource locator (URL) that comprises a hostname, and wherein said step (A) comprises:

causing said hostname to resolve to at least one server in said shared content delivery network.

9. A method as in claim 1, wherein the identifying step comprises:

determining the relative location of the client based at least in part on data corresponding to a cost of transmission between at least some of the repeater servers and the client.

10. A method as in claim 9, wherein the identifying step further comprises:

using load measurements to select the identified repeater server from the repeater servers considered in the determining step.

11. A method as recited in claim 1, wherein the content source comprises an origin server of the first content provider.

12. A method for delivering resources to clients from a shared network of servers on behalf of a plurality of resource providers, wherein at least a first resource maintained on a content source associated with one of said plurality of resource providers references a second resource, the method comprising:

responsive to a request to serve the first resource to a client from the content source, attempting to serve the second resource to the client from a particular resource server in said shared network of resource servers by;

(a1) if a copy of the second resource is available on the particular resource server, serving the copy of the second resource to the client from the particular resource server;

otherwise,

(a2) replicating the second resource on the particular resource server and then serving the replicated second resource to the client from the particular resource server,

said particular resource server having been selected based, at least in part, on a relative location corresponding to said client and at least some of the resource servers.

13. A method as recited in claim 12, further comprising:

determining the relative location of the client based at least in part on data corresponding to a cost of transmission between at least some of the repeater servers and the client.

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

using load measurements to select the particular resource server from the resource servers considered in the determining step.

15. A method as recited in claim 12, wherein the replicating step (a2) comprises:

said particular resource server attempting to obtain a copy of the second resource from the content source.

16. A method as recited in claim 12, wherein the replicating step (a2) comprises:

said particular resource server attempting to obtain a copy of the second resource from another resource server

17. A method as recited in claim 12, wherein the second resource is originally associated, via a first uniform resource locator (URL), with the content source, said first URL including a first domain name that is resolvable to said content source, and wherein the method further comprises:

causing the second resource to be associated with at least some of the plurality of resource servers via a second URL, wherein said second URL includes a second domain name at least partially distinct from the first domain name, said second domain name being resolvable to at least some of the resource servers in said shared network of resource servers.

18. A method as recited in claim 17, wherein the second URL is formed by prepending data to the first domain name in the first URL.

19. A method as in claim 12, wherein the first resource references the second resource with a uniform resource locator (URL) that includes a hostname, and wherein the method further comprises:

causing said hostname in said URL to resolve to at least some of said resource servers in said shared network of resource servers.

20. A method as recited in claim 12, wherein the second resource comprises video content.

21. A method for delivering resources to clients in a distributed computing framework, said framework including a shared network formed by a plurality of repeater servers operable to serve resources to clients on behalf of the plurality of content providers, wherein at least a first resource associated with a first content provider of said plurality of content providers references a second resource, the method comprising:

(A) responsive to a request that causes the first resource to be served to a client from a content source distinct from said plurality of repeater servers, selecting a repeater server in the network from which to serve the second resource to the client, said selecting being based at least in part on a location corresponding to said client; and

(B) responsive to the selected repeater server being requested to serve the second resource;

(b1) if a copy of the second resource is available on the selected repeater server, serving the copy of the second resource to the client from the selected repeater server;

otherwise,

(c2) replicating the second resource on the selected repeater server and then serving the replicated second resource to the client from the selected repeater server.

22. A method as defined in claim 21, wherein the selecting step (A) is performed at least in part by a software component co-located with the content source.

23. A method as in claim 21, wherein the selecting step (A) is performed after the request that caused the first resource to be served to the client from the content source.

24. A method as recited in claim 21, wherein the selecting step (A) comprises:

selecting the repeater server based at least in part on load conditions on at least some of the plurality of repeater servers.

25. A method as in claim 21, wherein the first resource references the second resource using a textual reference that comprises a hostname, the method further comprising:

causing said hostname to resolve to said shared network.