Using the ALTO Service, networking applications can request through the ALTO protocol information about the underlying network topology from the ISP or Content Provider. The ALTO Service provides information such as preferences of network resources with the goal of modifying network resource consumption patterns while maintaining or improving application performance. This document describes, in one example, an ALTO server that intersects network and cost maps for a first network with network and cost maps for a second network to generate a master cost map that includes one or more master cost entries that each represent a cost to traverse a network from an endpoint in the first network to an endpoint in the second network. Using the master cost map, a redirector may select a preferred node in the first network with which to service a content request received from a host in the second network.