Patent ID: 8676918

Claim:
A computer-implemented method for request routing comprising: obtaining a DNS query from a client computing device at a first DNS server, wherein the DNS query corresponds to a requested resource associated with an original resource identifier provided by a content provider and wherein the first DNS server corresponds to a content delivery network service provider that is different from the content provider; selecting a second DNS server from one or more alternative DNS servers based at least in part on at least a calculated distance associated with each of the one or more alternative DNS servers and performance measurement information associated with each of the one or more alternative DNS servers; obtaining an alternative resource identifier corresponding to the selected second DNS server, wherein the alternative resource identifier includes information for causing a DNS query to resolve to a domain corresponding to the content delivery service provider; transmitting the alternative resource identifier to the client computing device; obtaining a subsequent DNS query from the client computing device at a second DNS server, wherein the subsequent DNS query corresponds to the alternative resource identifier provided by the content delivery network service provider and wherein the second DNS server corresponds to the content delivery network service provider that is different from the content provider; determining whether the second DNS server is authoritative to the subsequent DNS query; selecting a cache component for providing content associated with the original resource request if the second DNS server is authoritative to the subsequent DNS query; and transmitting information identifying the selected cache component if the second DNS server is determined to be authoritative.