A content delivery system comprising: a plurality of points of presence, POPs, each POP comprising one or more computing devices configured to retrieve and transmit content, and each POP including at least two communication links via which the computing devices communicate with the POP; a domain name system, DNS, server configured to receive, from a DNS resolver, requests to resolve a hostname of the content delivery system into a network address of a POP of the plurality of POPs; and one or more processors implementing a demand analysis service, the one or more processors configured with specific computer-executable instructions to: determine an association between the DNS resolver and a subnetwork comprising one or more client computing devices, the association indicating that a client computing device within the subnetwork is expected to communicate with the DNS resolver in order to resolve the hostname of the content delivery system; select a first POP, from the plurality of POPs, for potential assignment to the DNS resolver based at least partly on a latency of communications between the subnetwork and the first POP; identify, based at least in part on routing information available at the first POP, a first communication link of the at least two communication links between the first POP and the subnetwork over which communications are routed; determine that a volume of communications between the subnetwork associated with the DNS resolver and the selected first POP does not exceed a network capacity of the first communication link; and transmit to the DNS server an indication that the first POP has been assigned to the DNS resolver, wherein assignment of the first POP to the DNS resolver causes the DNS server to respond to resolution requests from the DNS resolver with a network address of the first POP. a plurality of points of presence, POPs, each POP comprising one or more computing devices configured to retrieve and transmit content, and each POP including at least two communication links via which the computing devices communicate with the POP; a domain name system, DNS, server configured to receive, from a DNS resolver, requests to resolve a hostname of the content delivery system into a network address of a POP of the plurality of POPs; and one or more processors implementing a demand analysis service, the one or more processors configured with specific computer-executable instructions to: determine an association between the DNS resolver and a subnetwork comprising one or more client computing devices, the association indicating that a client computing device within the subnetwork is expected to communicate with the DNS resolver in order to resolve the hostname of the content delivery system; select a first POP, from the plurality of POPs, for potential assignment to the DNS resolver based at least partly on a latency of communications between the subnetwork and the first POP; identify, based at least in part on routing information available at the first POP, a first communication link of the at least two communication links between the first POP and the subnetwork over which communications are routed; determine that a volume of communications between the subnetwork associated with the DNS resolver and the selected first POP does not exceed a network capacity of the first communication link; and transmit to the DNS server an indication that the first POP has been assigned to the DNS resolver, wherein assignment of the first POP to the DNS resolver causes the DNS server to respond to resolution requests from the DNS resolver with a network address of the first POP. determine an association between the DNS resolver and a subnetwork comprising one or more client computing devices, the association indicating that a client computing device within the subnetwork is expected to communicate with the DNS resolver in order to resolve the hostname of the content delivery system; select a first POP, from the plurality of POPs, for potential assignment to the DNS resolver based at least partly on a latency of communications between the subnetwork and the first POP; identify, based at least in part on routing information available at the first POP, a first communication link of the at least two communication links between the first POP and the subnetwork over which communications are routed; determine that a volume of communications between the subnetwork associated with the DNS resolver and the selected first POP does not exceed a network capacity of the first communication link; and transmit to the DNS server an indication that the first POP has been assigned to the DNS resolver, wherein assignment of the first POP to the DNS resolver causes the DNS server to respond to resolution requests from the DNS resolver with a network address of the first POP.