Multicast in Delay Tolerant Networks Using Probabilities and Mobility Information
José Santiago, Augusto Casaca and Paulo Rogério Pereira
Networks with frequent and long duration partitions prevent common Internet protocols from working successfully. For protocols to work properly in these Delay/Disruption Tolerant Networks (DTNs), a new protocol layer was proposed that acts on top of the transport layer for the end-to-end exchange of messages (called bundles) taking advantage of scheduled, predicted, opportunistic or permanent connectivity. In this paper, we propose and evaluate a multicast extension to the DTN’s unicast PROPHET protocol. A multicast protocol is useful to reduce the number of copies of packets when they are sent to multiple destinations. PROPHET routes packets based on estimates of the probability of nodes meeting. We show by simulation that by using just one byte for transferring mobility information between nodes, a good clue is given about the region where mobile nodes are, which can be used by the multicast protocol to decide where to forward messages. Additionally, we show that if the number of contacts between nodes is above a minimum threshold, a pseudo multicast tree will exist, multicast works efficiently and message replications are minimized.
Keywords: Delay/disruption tolerant networks, connection disruption, multicast.