Adaptive Multicast Routing For Delay Tolerant Networks

Delay tolerant network (DTN) is a network model which always suffers from frequent and long-duration partitions due to the sparse node distribution and the frequent node mobility. Multicast in DTN is a desirable feature for applications where some form of group communication is in demand. For most of the existed DTN routing protocols, intermediate nodes carry packets all along while waiting for available forward links, in which a lot of buffer spaces can be consumed. Besides, some make decision based on the global flooding information and the spread of required information consumes valuable bandwidth.In this paper, we present a multicast routing protocol for DTN: ECAM (Epidemic-based Controlled Flooding and Adaptive Multicast for Delay Tolerant Networks). It requires neither a partial nor a global view of the network, nor does it require maintaining any mesh- or tree-like structure for multicasting, which shows a strong adaptability to DTN. Besides, by means of limiting the time and range of message transmission, the huge consumption of network resources caused by flooding can be saved. Meanwhile, with the adaptive mechanism, ECAM can work well under diverse network conditions with different node densities.By performing simulations under QualNet 4.0 network simulator,we study to what extend can the performance of ECAM be influenced by the protocol parameter values. Besides, we study its performance through comparative simulations with the standard Epidemic multicast routing protocol while changing the simulation scenarios. The simulation results show that ECAM could outperform existing Epidemic approaches. Our routing strategies can achieve higher message delivery ratios and lower control message copies.