Patent ID: 8645539

Claim:
A content delivery network (CDN) for delivering content over the Internet using a plurality of points of presence (PoPs), wherein the CDN is configured to deliver content for others, the CDN comprising: a domain resolution service (DNS) server, wherein: each of the plurality of PoPs includes a plurality of content servers; the DNS server is located in one of the PoPs; the DNS server generates a list of ones of the content servers that are considered available in the one of the PoPs; the DNS server is configured to receive a first domain resolution request at a first point in time, and produces a first DNS solution in response thereto, the first DNS solution including a first plurality of IP addresses of content servers that are considered available at the first point in time; the DNS server is configured to receive a second domain resolution request at a second point in time, and produces a second DNS solution in response thereto, the second DNS solution including a second plurality of content server IP addresses of content servers that are considered available at the second point in time; and the DNS server is configured to: receive one or more utilization measurements to assess an operating status of each of the content servers in the one of the PoPs, determine that a given one of the content servers should be removed from the list of servers considered available when its utilization measurement exceeds a first threshold, and determine that the given one of the content servers should be restored to the list of servers considered available when its utilization measurement is lower than a second threshold, the second threshold being lower than the first threshold.