Abstract In this paper we present Captain Cook, a service that

continuously monitors resources in the Internet, and allows clients to locate resources using this information. Captain Cook maintains a tree-based representation of all the collected resource information. The leaves in the tree contain directly measured resource information, while internal nodes are generated using condensation functions that aggregate information in child nodes. We present examples of how such information may be used for cluster management, application-level routing and placement of servers, and pervasive computing. The nodes are automatically replicated, updates being propagated using a novel hierarchical gossip protocol. We analyze how well this protocol behaves, and conclude that updates propagate quickly in spite of scale, failed nodes, and message loss. We describe how Captain Cook can be made secure using Public Key Certificates without compromising its scalability