Dynamicity of participants: Some P2P systems, such as [10], assume a fixed set of nodes in the system. However, one of the greatest potential strengths of P2P systems is when they eschew reliance on dedicated infrastructure and allow peers to leave the system at will. Even under these conditions, participants typically have broadly varying availability characteristics. Some peers are akin to servers: their membership in the system stays largely static. Others have much more dynamic membership, joining and leaving the system at will. In a configuration where original data is distributed uniformly across the network, including on nodes that frequently disappear, it may become impossible to.