Routing Protocols in Delay Tolerant Networks : A Comparative Survey

† The corresponding author. Abstract: Delay Tolerant Networks (DTNs) are a class of emerging networks that experience frequent and longduration partitions. Compared with the conventional networks, the distinguished feature is that there is no endto-end connectivity between source and destination. The network topology may change dynamically and randomly, and the non-existence of an end-to-end path poses a number of challenges in routing in DTNs. In this paper, we survey the state-of-the-art routing protocols and give a comparison of them with respect to the important challenging issues in DTNs. The routing protocols are classified into two categories based on which property is used to find the destination: flooding families and forwarding families. The pros and cons as well as performance are disccused and compared for the routing protocols.