Scalable facility placement for communication cost reduction in wireless networks

Wireless network nodes, recently powerful enough to assume sophisticated roles, have changed the angle of studying service communication costs in modern, typically large-scale and inherently dynamic, network environments. Communication cost minimization for using a certain service, is one of the challenging issues in these environments. Its ensuing optimization problem is not only difficult (NP-hard and requires global information), but also its centralized solution is non-scalable. The approach followed in this paper is a distributed one based on local information. First, a facility replication method ensuring overall communication cost reduction is proposed and analyzed. No additional overhead is introduced and the cost of hosting a new facility is also taken into account. Second, and aiming at reducing the communication cost for using a service, a policy that employs facility replication in conjunction with facility migration, is introduced. This policy is easy to implement since it relies on information locally available at the facility node, and its efficiency and limitations are also analyzed and discussed here. Simulation results are presented, supporting the analytical findings and demonstrating a significant overall cost reduction when the proposed policy is implemented.