Analysis of push-type epidemic data dissemination in fully connected networks

Consider a fully connected network of nodes, some of which have a piece of data to be disseminated to the whole network. We analyze the following push-type epidemic algorithm: in each push round, every node that has the data, i.e., every infected node, randomly chooses c other nodes in the network and transmits, i.e., pushes, the data to them. We write this round dynamically as a random walk whose each step corresponds to a random selection of one of the infected nodes, which gives an efficient way of representing the distribution of the result of each round. We use this to compute the expected number of rounds so that a given percentage of the network is infected and continue a numerical comparison of the push algorithm and the pull algorithm (where the susceptible nodes randomly choose peers) initiated in an earlier work. We then derive the fluid and diffusion limits of the random walk as the network size goes to ∞ and derive a number of properties of the push algorithm: 1) the number of newly infected nodes in a push round, and the number of random selections needed so that a given percent of the network is infected, are both asymptotically normal 2) for large networks, starting with a nonzero proportion of infected nodes, a pull round infects slightly more nodes on average 3) the number of rounds until a given proportion λ of the network is infected converges to a constant for almost all λ ∈ (0, 1). Numerical examples for all of the theoretical results are provided.