Some of the recent applications using wireless communications (wildlife monitoring, inter-vehicles communication, battlefield communication,...) are characterized by challenging network scenarios. Most of the time there is not a complete path from a source to a destination (because the network is sparse), or such a path is highly unstable and may change or break while being discovered (because of nodes mobility and time-variations of the wireless channel). Networks under these conditions are usually referred to as Intermittently Connected Networks (ICNs) or Delay Tolerant Networks (DTNs). In such scenarios information delivery is then based on the store-carry-forward paradigm: a mobile node first stores the routing message from the source, carries it from a physical location to another and then forwards it to an intermediate node or to the destination.