Middleware solutions aim at facilitating the design of distributed systems by providing high-level mechanisms for the management of coordination and communication among application components, as well as the discovery of devices and data on behalf of users and applications. We consider two core services in the context of middleware for mobile ad-hoc networks. The .rst service provides support for logical mobility: by dynamically changing application topology the middleware can improve communication efficiency of applications in terms of bandwidth occupation and communication latency. The second service addresses the problem of finding the node that stores a particular data item by including information about the physical position of nodes in the design of the lookup protocol. Both services are based on the consideration that communication costs mainly depend on nodes? physical position, and that dynamical adaptation of communication schemes to network topology can provide benefits in terms of network efficiency.