DPCP: A protocol for optimal pull coordination in decentralized social networks

Social Networking Service has become an essential part of our life today. However, many privacy concerns have recently been raised due to the centralized nature of such services. Decentralized Social Network (DSN) is believed to be a viable solution for these problems. In this paper, we design a protocol to coordinate the pulling operation of DSN nodes. The protocol is the result of forward engineering via utility maximization that takes communication layer congestion level as well as social network layer centrality into consideration. We solve the pulling rate control problem using the primal-dual approach and prove that the protocol can converge quickly when executed in a decentralized manner. Furthermore, we develop a novel “drumbeats” algorithm to estimate node centrality purely based on passively-observed information. Simulation results show that our protocol reduces the average message propagation delay by 15% when comparing to the baselined Fixed Equal Gap Pull protocol. In addition, the estimated node centrality matches well with the ground-truth derived from the actual topology of the social network.