Hybrid CDN-P2P architecture: Replica content Placement Algorithms

Hybrid CDN-P2P architecture is a combination of pure Content Distribution Networks (CDNs) and Peer-to-Peer (P2P) networks. This architecture relies on CDN and P2P complementary advantages. This paper discusses Replica Placement Algorithms (RPAs) in hybrid CDN-P2P architecture. There are two constraints in the used model; one is the server storage capacity constraint and another is an upper bound for the number of replicas for each content. RPA has been considered as a constraint p-median problem. Constraint p-median problem belongs to the NP-hard problems. Therefore, some kinds of heuristic algorithms are used to solve this problem. Heuristic algorithms´ results are compared with Constraint P-Median (CPM) problem that presented by Sun. The formulations take into account both the transmitting and storage costs. The simulation results show that in hybrid CDN-P2P architecture, the greedy algorithm has the lowest cost among heuristic. It is showed that replication cost of hybrid CDN-P2P networks is lower than CDNs.