Bandwidth- and Latency-Aware Peer-to-Peer Instant Friendcast for Online Social Networks

Online Social Networks (OSNs) are more and more popular recently, people may through them interact with each other for the purpose of social intercourse. The client/server OSN architecture brings about the bottleneck of bandwidth and computation. It leads to the scalability problem and the communication latency increases as users grows. This paper proposes a bandwidth- and latency-aware peer-to-peer (P2P) instant friend cast scheme for every user (or peer) in OSNs to construct a friend cast tree (FCT) to send instant messages to all of its friends. A lightweight server is responsible for only easy tasks, such as logining and maintaining peer information, to facilitate the tree construction. A peer logins to the server to obtain the list of friends and their Vivaldi coordinates, which are computed by every peer in a distributed way to estimate the latency between peers. The proposed scheme also uses Available Out-Degree Estimation (AODE) to evaluate the proper out-degree of a peer, and then uses Degree-Adapted Greedy Tree Algorithm (DATGA) to construct FCT. The scheme is simulated and compared with other relevant ones to show its advantages.