Point of presence management in request routing

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;
• obtaining an alternative resource identifier based at least in part on at least a calculated distance associated with each of one or more alternative network components and performance measurement information associated with each of the one or more alternative network components;
• determining whether the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier;
• selecting a cache component for providing content associated with the original resource request if the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier;
• and
• transmitting information identifying the selected cache component if the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier.

A system for request routing comprising:

• a first network point of presence associated with a content delivery network service provider, wherein the first network point of presence includes a DNS server that is operative to:
• obtain a DNS query from a client computing device, wherein the DNS query corresponds to a requested resource associated with an original resource identifier provided by a content provider and wherein the content delivery network service provider is different from the content provider;
• select 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;
• obtain 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;
• and
• transmit the alternative resource identifier to the client computing device;
• a second network point of presence associated with the content delivery network service provider, wherein the second network point of presence includes the second DNS server and wherein the second DNS server is operative to:
• obtain a subsequent DNS query from the client computing device, wherein the subsequent DNS query corresponds to the alternative resource identifier provided by the content delivery network service provider;
• determine whether the second DNS server is authoritative to the subsequent DNS query;
• select 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
• transmit information identifying the selected cache component if the second DNS server is determined to be authoritative.

A system for request routing comprising:

• a first network point of presence associated with a content delivery network service provider, wherein the first network point of presence includes a first DNS server that is operative to:
• obtain a DNS query from a client computing device, wherein the DNS query corresponds to a requested resource associated with an original resource identifier provided by a content provider and wherein the content delivery network service provider is different from the content provider;
• obtain an alternative resource identifier based at least in part on at least a calculated distance associated with each of one or more alternative network components and performance measurement information associated with each of the one or more alternative network components;
• determine whether the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier;
• select a cache component for providing content associated with the original resource request if the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier;
• and
• transmit information identifying the selected cache component if the first DNS server would be authoritative for a DNS query corresponding to the alternative resource identifier.