Integrated Adaptive Anycast for Content Distribution

• US 20110153719A1
• 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: Santoro, Mario, Brotman, Herani, Miros, James, Spatscheck, Oliver, Van der Merwe, Jacobus, Glasser, Alan L.
• Granted Patent: US 8,560,598 B2
• Time in Patent Office: Days
• US Class Current: 709/203
• CPC Class Codes: H04L 43/08 Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
• CPC Class Codes: H04L 45/126 minimising geographical or physical path length
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/1021 based on client or server locations

Abstract

A system includes first and second cache servers a domain name server, and a route controller. The cache servers are each configured to respond to an anycast address. Additionally, the first cache server is configured to respond to a first unicast address, and the second cache server is configured to respond to a second unicast address. The router controller configured to determine wither the status of the first cache server is non-overloaded, overloaded, or offline. The route controller is further configured to instruct the domain name server to provide the second unicast address when the status is overloaded or offline, and modify routing of the anycast address to direct a content request sent to the anycast address to the second cache server when the status is offline. The domain name server is configured to receive a request from a requestor for a cache server address. Additionally, the domain name server is configured to provide an anycast address to the requestor when the status of the first cache server is non-overloaded, and provide the second unicast address to the requestor when the status of the first cache server is offline or overloaded.

Claims

1. A system comprising:

first and second cache servers, the cache servers each configured to respond to an anycast address, the first cache server configured to respond to a first unicast address, and the second cache server configured to respond to a second unicast address;

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

receive a request from a requestor for a cache server address;

provide an anycast address to the requestor when a status of the first cache server is non-overloaded; and

provide the second unicast address to the requestor when the status of the first cache server is offline or overloaded; and

a route controller, the router controller configured to;

determine the status of the first cache server, the status being non-overloaded, overloaded, or offline;

instruct the domain name server to provide the second unicast address when the status is overloaded or offline; and

modify routing of the anycast address to direct a content request sent to the anycast address to the second cache server when the status is offline.

2. The system of claim 1 wherein the domain name server is further configured to provide the first anycast address to the requestor when the status of the first cache server is non-overloaded and the requestor is associated with an unstable network.

3. The system of claim 1 wherein the routing of the anycast addresses directs the content request sent to the anycast address to the first cache server when the status is non-overloaded or overloaded.

4. The system of claim 1 wherein the route controlled is further configured to receive a notification from the first cache server.

5. The system of claim 4 wherein the status of the first cache server is offline when a notification from the first cache server is not received.

6. The system of claim 4 wherein the status of the first cache server is overloaded when the notification from the first cache server is received and the load exceeds a threshold.

7. The system of claim 4 wherein the status of the first cache server is non-overloaded when the notification from the first cache server is received and the load does not exceed a threshold.

8. The system of claim 6 wherein the load of the first cache server is based on network bandwidth, CPU utilization, memory utilization, number of requests being served, or any combination thereof for the respective cache server.

9. A domain name server comprising:

a processor configured to;

receive a plurality of address requests from one or more requestors for a cache address, the requestor being part of a serving region;

identify a first cache server serving content requests sent to an anycast address from the serving region;

determine a load of the first cache server;

provide a unicast address of an alternate cache server in response to the address requests when the load exceeds an overloaded threshold;

provide the anycast address in response to the address requests when the load is at or below a pre-overloaded threshold; and

provide the anycast address in response to a first portion of the address requests and provide the unicast address in response to a second portion of the address requests when the load exceeds the pre-overloaded threshold and is at or below the overloaded threshold.

10. The domain name server of claim 9 wherein the alternate cache servers is selected from a list of cache servers.

11. The domain name server of claim 9 wherein the alternate cache server is based on a load of each of the cache servers.

12. The domain name server of claim 9 wherein the overloaded threshold is at least about 80% of the capacity of the first cache server.

13. The domain name server of claim 9 wherein the pre-overloaded threshold is at least about 60% of the capacity of the first cache server.

14. The domain name server of claim 9 wherein the load of the first cache server is based on network bandwidth, CPU utilization, memory utilization, number of requests being served, or any combination thereof.

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

instructions to determine the status of a serving region cache server, the status being one of non-overloaded, overloaded, or offline;

instructions to instruct a domain name server to provide a unicast address for an alternate cache server when the status is overloaded or offline; and

instructions to modify routing of an anycast address to direct a content request sent to the anycast address to the alternate cache server when the status of the serving region cache server is offline.

16. The computer readable medium of claim 15 wherein the serving region includes a plurality of client systems sharing a common ingress point.

17. The computer readable medium of claim 15 further comprising instructions to obtain load information from the serving region cache server.

18. The computer readable medium of claim 17 wherein the load information includes network bandwidth, CPU utilization, memory utilization, number of requests being served, or any combination thereof.

19. The computer readable medium of claim 15 further comprising instructions to identify the alternate cache server.

20. The computer readable medium of claim 19 wherein the instructions to identify the alternate cache server include determining load information for each of the plurality of cache servers.