Greedy heuristic for replica server placement in Cloud based Content Delivery Networks

Recently, Cloud based Content Delivery Network (CCDN) has emerged as efficient content delivery architecture to provide content delivery services with improved Quality of Service (QoS), scalability and resource efficiency. Replica server placement is a key design issue in CCDNs and involves deciding the placement of replica servers on geographically dispersed cloud sites that minimizes the operational cost and satisfies QoS of the end-users. Since replica server placement problem is NP-hard, it is necessary to design an efficient heuristic for CCDNs. In this paper, we propose an efficient greedy heuristic for the replica server placement problem. The heuristic consists of two main procedures: placement and refinement. The placement procedure obtains an initial placement of replica servers on cloud sites with low operational cost. The refinement procedure removes the redundant cloud sites to reduce the operational cost further. The simulation results demonstrate that the proposed greedy heuristic outperforms the existing greedy heuristics in terms of computation time and the operational cost.