Patent ID: 8380851

Claim:
A content delivery network (CDN) for delivering content over the Internet using a plurality of points of presence (PoPs) that are geographically distributed, wherein the CDN is configured to deliver content for others, the CDN comprising: a domain resolution service (DNS) server, wherein: the plurality of PoPs include a first PoP, a second PoP and a third PoP; the DNS server is located in the first PoP; the DNS server is configured to receive a first domain resolution request and produces a first DNS solution, the first domain resolution request corresponding to a first domain, the DNS server is configured to receive a second domain resolution request and produces a second DNS solution, the second domain resolution request corresponding to a second domain, the first and second domains being the same, and the DNS server is configured to receive a third domain resolution request and produces a third DNS solution, the third domain resolution request corresponding to a third domain, the first and third domains being different; a plurality of caching servers located within the plurality of PoPs, wherein the plurality of caching servers correspond to a plurality of addresses; and an interface with the Internet for the first PoP, wherein: the interface is configured to: receive a plurality of domain resolution requests, and transmit a plurality of DNS solutions, the plurality of DNS solutions comprise the first, second and third DNS solutions, the plurality of domain resolution requests comprise the first, second and third domain resolution requests, the first DNS solution comprises a first plurality of addresses corresponding to at least a first subset of the plurality of caching servers, wherein a first number characterizes how many caching servers are in the first subset, and wherein the first plurality of addresses includes a first address, the first DNS solution is provided at a first time, the second DNS solution comprises a second plurality of addresses corresponding to at least a second subset of the plurality of caching servers, wherein a second number characterizes how many caching servers are in the second subset, the second number being the same as the first number, the second DNS solution is provided at a second time, the second time being different than the first time, the third DNS solution comprises a third plurality of addresses corresponding to at least a third subset of the plurality of caching servers, wherein a third number characterizes how many caching servers are in the third subset, the third number being different than the first number, the first DNS solution is different from the second DNS solution in that the first subset includes the first address for a first caching server, wherein the first address is not in the second subset.