Patent attributes
Techniques for dynamic content delivery network (CDN) selection using the domain name service (DNS) protocol are described. A DNS resolver utilizes a network identifier provided within a DNS query seeking to resolve a domain to select between different CDNs. The selection can be based on an analysis of network metric summary data corresponding to the CDNs from the perspective of an approximate location of the requesting client, as determined via the network identifier as a proxy. The selection process and involved network metric types can be configured by the user associated with the domain via a selection policy. Network metrics can be provided by the user or collected based on reported data generated by remote clients through provided metric-generating code, and thereafter transformed into network metric summary data that is used for resolution.