Multi-Autonomous System Anycast Content Delivery Network

• US 20110153941A1
• Filed: 12/22/2009
• Published: 06/23/2011
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Spatscheck, Oliver, Van der Merwe, Jacobus, Al-Qudah, Zakaria, Lee, Seungjoon, Rabinovich, Michael
• Granted Patent: US 8,607,014 B2
• Time in Patent Office: Days
• US Class Current: 711/119
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system
• CPC Class Codes: H04L 67/1004 Server selection for load balancing
• 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 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests

Abstract

A content delivery network includes first and second sets of cache servers, a domain name server, and an anycast island controller. The first set of cache servers is hosted by a first autonomous system and the second set of cache servers is hosted by a second autonomous system. The cache servers are configured to respond to an anycast address for the content delivery network, to receive a request for content from a client system, and provide the content to the client system. The first and second autonomous systems are configured to balance the load across the first and second sets of cache servers, respectively. The domain name server is configured to receive a request from a requestor for a cache server address, and provide the anycast address to the requestor in response to the request. The anycast island controller is configured to receive load information from each of the cache servers, determine an amount of requests to transfer from the first autonomous system to the second autonomous system; send an instruction to the first autonomous system to transfer the amount of requests to the second autonomous system.

Claims

1. A content delivery network comprising:

a first set of cache servers hosted by a first autonomous system and a second set of cache servers hosted by a second autonomous system, the first autonomous system configured to balance a first load among the first set of cache servers and the second autonomous system configured to balance a second load among the second set of cache servers, each of the cache servers configured to;

respond to an anycast address for the content delivery network; and

receive a request for content from a client system and provide the content to the client system;

a domain name server, the domain name server configured to;

receive a request for a cache server address; and

provide the anycast address in response to the request for the cache server address; and

an anycast island controller configured to;

receive load information from each of the cache servers;

determine an amount of requests for content to transfer from the first autonomous system to the second autonomous system; and

send an instruction to the first autonomous system to transfer the amount of requests for content to the second autonomous system.

2. The content delivery network of claim 1 further comprising a third set of cache servers hosted by a third autonomous system, the third autonomous system configured to balance a third load among the third set of cache servers, wherein the anycast island controlled is further configured to determine a second amount of requests for content to transfer from the first autonomous system to the third autonomous system;

and send an instruction to the first autonomous system to transfer the second amount of requests for content to the third autonomous system.

3. The content delivery network of claim 1 wherein the domain name server is further configured to:

receive a second request for a cache server address; and

provide a unicast address in response to a second request for a cache server address, the unicast address corresponding to an available cache server.

4. The content delivery network of claim 1 wherein the anycast island controller is further configured to determine if a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

5. The content delivery network of claim 4 wherein the anycast island controller is further configured to notify the first autonomous system when a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

6. The content delivery network of claim 1 wherein the anycast island controller is further configured to verify the amount of requests shifted from the first autonomous system to the second autonomous system.

7. The content delivery network of claim 6 wherein the anycast island controller is further configured to notify the first autonomous system of a failure to shift the amount of requests to the second autonomous system.

8. The content delivery network of claim 1 wherein the load information includes network bandwidth, CPU utilization, memory utilization, number of requests being served, or any combination thereof.

9. The content delivery network of claim 1 wherein the first autonomous system is configured to balance the load across the first set of cache servers by controlling the routing of the anycast address within the first autonomous system.

10. An anycast island controller comprising:

a processor configured to;

receive load information from a first set of cache servers hosted by a first autonomous system and a second set of cache servers hosted by a second autonomous system, the first autonomous system configured to balance a first load among the first set of cache servers and the second autonomous systems configured to balance a second load among the second set of cache servers;

determine an amount of requests to transfer from the first autonomous system to the second autonomous system; and

send an instruction to the first autonomous system to transfer the amount of requests to the second autonomous system.

11. The anycast island controller of claim 10 wherein the processor is further configured to determine if a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

12. The anycast island controller of claim 11 wherein the processor is further configured to notify the first autonomous system when a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

13. The anycast island controller of claim 10 wherein the processor is further configured to verify the amount of requests shifted from the first autonomous system to the second autonomous system.

14. The anycast island controller of claim 13 wherein the processor is further configured to notify the first autonomous system of a failure to shift the amount of requests to the second autonomous system.

15. The anycast island controller of claim 10 wherein the load information includes network bandwidth, CPU utilization, memory utilization, number of requests being served, or any combination thereof.

20. The computer readable medium of claim 15 wherein the computer readable medium further comprises instructions to notify the first autonomous system of a failure to shift the amount of requests to the second autonomous system.

16. A computer readable medium comprising a plurality of instructions to manipulate a processor, the plurality of instructions comprising:

instructions to receive load information from a first set of cache servers hosted by a first autonomous system and a second set of cache servers hosted by a second autonomous system, the first autonomous system configured to balance a first load among the first set of cache servers and the second autonomous systems configured to balance a second load among the second set of cache servers;

instructions to determine an amount of requests to transfer from the first autonomous system to the second autonomous system; and

instructions to send an instruction to the first autonomous system to transfer the amount of requests to the second autonomous system.

17. The computer readable medium of claim 16 wherein the computer readable medium further comprises instructions to determine if a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

18. The computer readable medium of claim 17 wherein the computer readable medium further comprises instructions to notify the first autonomous system when a critically overloaded cache server and a cache server with a significant excess capacity are within the first autonomous system.

19. The computer readable medium of claim 16 wherein the computer readable medium further comprises instructions to verify the amount of requests shifted from the first autonomous system to the second autonomous system.