A scalable mobility-based replica allocation scheme in a mobile ad-hoc network.

Various issues on network routing in a mobile ad-hoc network (MANET) have been studied with outstanding results. However, there is still room for improvement with regard to data accessibility, especially when the number of nodes increases in the network. To enhance the data accessibility in a MANET, a few replica allocation schemes have been proposed. In these schemes, the nodes are partitioned into groups so that each group has as many different data items as possible. However, grouping in a MANET requires an enormous amount of communication cost, since the network topology is changed dynamically. In this paper, we propose a scalable replica allocation scheme in which the nodes are grouped based on the mobility of the nodes. Grouping in the proposed scheme is done with one-hop communications in a fully distributed manner. Within each group, replicas are allocated to the group nodes based on the estimated data access frequencies that are computed periodically by the allocator of the group. It turns out that grouping with mobility and utilizing the estimated access frequency information enhances the stability of the topology of each group as well as the data accessibility. We evaluate the proposed scheme by simulations with the Network Simulator NS-3 along with the analytical evaluations. The results of simulations and analytical evaluations demonstrate the effectiveness of the proposed scheme in terms of communication cost. The proposed scheme reduces the communication cost by 347.1 % on average over the existing replica allocation scheme, while achieving comparable data accessibility. [ABSTRACT FROM AUTHOR]