A mobile ad hoc network (MANET) is a network that allows mobile servers and clients to communicate in the absence of a fixed infrastructure. MANET is a fast growing area of research as it finds use in a variety of applications. In order to facilitate efficient data access and update, databases are deployed on MANETs. These databases that operate on MANETs are referred to as MANET databases. Since data availability in MANETs is affected by the mobility and power constraints of the servers and clients, data in MANETs are replicated. A number of data replication techniques have been proposed for MANET databases. This paper identifies issues involved in MANET data replication and attempts to classify existing MANET data replication techniques based on the issues they address. The attributes of the replication techniques are also tabulated to facilitate a feature comparison of the existing MANET data replication works. Parameters and performance metrics are also presented to measure the performance of MANET replication techniques. In addition, this paper also proposes criteria for selecting appropriate data replication techniques for various application requirements. Finally, the paper concludes with a discussion on future research directions.

Abstract. Mobile Ad-Hoc Networks, or MANETs, provide communication between free-roaming mobile hosts without a fixed infrastructure. These MANETs operate under conditions of limited battery power and may also experience frequent network partitioning. This paper introduces a data replication technique called REALM (REplication of data for A Logical group based MANET database). REALM takes advantage of application semantics when determining where to place replicas of data items. It also tries to predict network partitioning and disconnection ahead of time and creates copies of data items accordingly. Experiments show that REALM increases the percentage of successful transactions with or without the presence of network disconnection and partitioning.