An efficient replica placement heuristic for community WMNs

Recently, Wireless Mesh Networks (WMNs) have attracted much of interest from both academia and industry, due to their potential to provide an alternative broadband wireless Internet connectivity. However, due to different reasons such as multi-hop forwarding and the dynamic wireless link characteristics, the performance of current WMNs is rather low when clients are soliciting Web contents. Due to the evolution of advanced mobile computing devices; it is anticipated that the demand for bandwidth-onerous popular content (especially multimedia content) in WMNs will dramatically increase in the coming future. Content replication is a popular approach for outsourcing content on behalf of the origin content provider. This area has been well explored in the context of the wired Internet, but has received comparatively less attention from the research community when it comes to WMNs. There are a number of replica placement algorithms that are specifically designed for the Internet. But they do not consider the special features of wireless networks such as insufficient bandwidth, low server capacity, contention to access the wireless medium, etc. In this paper, we propose a distributed heuristic solution for the replica placement problem in WMNs. This problem is known to be NP-complete. Our heuristic considers the local popularity of an object replica. The local popularity can be defined as the relative demand for an object within a partition of the network compared to the whole network. The heuristic collects popularity information periodically to compute the number of replicas for future period requests. Using extensive simulation tests, we demonstrate the performance gain of our heuristic compared to other relevant ones.