Patent ID: 8195837

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 DNS server is configured to receive a second domain resolution request and produces a second DNS solution, the DNS server is configured to receive a third domain resolution request and produces a third DNS solution, and the first second and third domain resolution requests correspond to a same domain; 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 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, the second DNS solution is provided at a second time, the third DNS solution comprises a third plurality of addresses corresponding to at least a third subset of the plurality of caching servers, the third DNS solution is provided at a third time, 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, the first caching server is no longer allocated for DNS solutions corresponding to the domain after the first time and before the third time, the first caching server is no longer allocated for DNS solutions corresponding to the domain based, at least in part, on activity associated with the domain relative to a first threshold, the third DNS solution is different from the second DNS solution in that the third subset includes the first address for the first caching server, the first caching server is allocated for DNS solutions corresponding to the domain at the third time, and the first caching server is allocated for DNS solutions corresponding to the domain based, at least in part, on activity associated with the domain relative to a second threshold.