Accessing remote data is a challenging task in mobile ad hoc networks (MANETs). A common technique used to improve the performance of data access is replication, which improves the performance of data access in distributed systems at the cost of increased storage space and communication overhead. Due to strict resource constraint, node mobility and impairments of wireless transmission, applying replication schemes developed for distributed systems to MANETs directly leads to poor performance. In this paper, we develop a zone-based replication scheme for MANETs. In this scheme, every node proactively maintains replica distributing information within its replicating zone, which leads to the access from requesting node to the requested data item (including its replicas) distributed in its replicating zone can be satisfied directly. If requested data item is outside the replicating zone, reactive lookup process is invoked to find the node hosting the requested data item and the route to this node at the same time. Opportunistic data replicating is performed spontaneously with data transferring, and corresponding replica is allocated to nodes located in the replicating zone of the requesting node. Using cross-layer design, we illustrate how the hybrid adaptive routing technique, zone routing protocol, assists data lookup and replication to achieve high performance of data access. Simulation results have shown that our design is successful in a dynamic MANET.
