Patent ID: 8156243

Claim:
A 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; determining whether the first DNS server is authoritative to the DNS query; obtaining an alternative resource identifier based on information associated with the client computing device and the content provider if the DNS server is determined not to be authoritative, wherein the alternative resource identifier includes information for causing a DNS query to resolve to a domain corresponding to the content delivery service provider and request routing information not included in the original resource identifier; 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 is based on 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; and selecting a cache component for providing content associated with the original resource request if the second DNS server is authoritative to the second DNS query; and transmitting a network address identifying the selected cache component if the second DNS server is determined to be authoritative.