Optimal Forwarding in Multi-source Multicast over Mobile Ad Hoc Networks

Packet forwarding in a multicast routing protocol for mobile ad hoc networks is a significantly important issue since inefficient and superfluous forwarding results in considerable bandwidth waste. Moreover, it will bring in unnecessary transmission interference leading to frequent traffic congestion, large end-to-end delay and considerable packet delivery ratio degradation, and so forth. In this paper, we investigate the feasibility of improving the forwarding efficiency by making use of network coding in a multi-source multicast routing application over ad hoc networks. We present how and when packet forwarding can take advantage of network coding and how practical it is. We model such forwarding decision problem with a classical max-flow model and a distributed solution to such modeled problem is also illustrated. Eventually, an implementation is depicted based upon a well known multicast routing protocol without incurring and additional forwarding delay. Simulation results suggest that the proposed approach performs well especially when traffic flows at higher rate are injected.