Patent ID: 8856281

Claim:
A content delivery system comprising: a first cache server location including a first redirector and a first set of cache servers; a second cache server location including a second redirector and a second set of cache servers; and a domain name server that performs operations comprising: receiving a request for a cache server address; and providing an internet protocol version 6 anycast address; and wherein the first redirector performs operations comprising: receiving a content request from a client system, the content request addressed to the internet protocol version 6 anycast address; receiving load information from the first set of cache servers, wherein the load information comprises central processing unit information, memory utilization, a number of concurrent requests being served, and an amount of available bandwidth; receiving load information for the second cache server location from the second redirector; determining when a first cache server of the first set of cache servers is available, wherein the first cache server is available for only local requests when the first cache server has a load that is below an upper threshold for the first cache server and above a lower threshold for the first cache server, wherein the first cache server is available for both the local requests and transferred requests when the load is below the lower threshold, wherein the first cache server is unavailable when the load exceeds the upper threshold for the first cache server; forwarding the request to the first cache server when the first cache server is available; and forwarding the request to the second redirector when the first set of cache servers are unavailable; wherein the second redirector performs operations comprising: receiving load information from the second set of cache servers; receiving a content request forwarded from the first redirector; selecting a second cache server of the second set of cache servers based on the load information received from the second set of cache servers; and forwarding the request to the second cache server, wherein the second redirector utilizes a ranked list of alternate cache server locations and redirects the content request to the second cache server when the second cache server is a highest ranked alternate cache server location currently available; wherein each cache server of the first and second sets of cache servers performs operations comprising: receiving the content request forwarded from the first or second redirector; sending a response to the content request to the client system, the response including an internet protocol version 6 unicast address of the cache server as a source address, an internet protocol version 6 unicast address of the client system as a destination address, and the internet protocol version 6 anycast address as a home address; and providing the content to a requestor.