Search time in unstructured peer-to-peer networks with clustered demands

Search time as a function of the number of replicas of a queried object provides a key component to understanding system behavior in peer-to-peer networks. The analytical work in this area so far has assumed a uniform distribution of file replicas throughout the network with an implicit or explicit assumption of uniform file popularity distribution whereas, in reality, there is clear evidence of clustering in file popularity patterns. In this paper, we provide mechanisms for modeling clustering in file popularity distributions and the consequent non-uniform distribution of file replicas. We provide results for the search time in such networks for both random walk and flooding search mechanisms.