A system and method for management and processing of resource requests is provided. A content delivery network service provider receives a DNS query from a client computing device. The DNS query corresponds to a requested resource from the client computing device. The content delivery network service provider associates the client computing device with a cluster of other client computing devices. Based on routing information for the cluster, the content delivery network service provider routes the DNS query. The process can further include monitoring performance data associated with the delivery of the requested resource and updating the routing information for the cluster based on the performance data for use in processing subsequent requests from client computing devices in the cluster.