Distributed Coverage of Ego Networks in F2F Online Social Networks

Although most online social networks rely on a centralized infrastructure, several proposals of Distributed Online Social Networks (DOSNs) have been recently presented. Since in DOSNs user profiles are stored on the peers of the users belonging to the network, one of the main challenges comes from guaranteeing the profile availability when the owner of the data is not online. In this paper, we propose a DOSN based on a friend-to-friend P2P overlay where the user's data is stored only on friend peers. Our approach is based on the ego-network concept, which models the social network from the local point of view of a single user. We propose a distributed algorithm which is based on the notion of coverage of the ego-network and assures that users store their data only on the peers of their friends, and that each online user can retrieve the private data of its offline friends through a common online friend. We formalize this as a Neighbour Dominating Set problem. A set of experimental results conducted on real Facebook dataset show the effectiveness of our approach.