Reliable cross-layer multicast with local backtracking for improving transmission control protocol performance in ad hoc networks

The conventional layered protocols in ad hoc networks tend to suffer from the inability to distinguish between losses due to route failures and congestion because of the inflexible structure. Recently, in efforts to overcome the challenges of dynamic environment, there have been increased interests in protocols that rely on interactions between different layers. The authors propose a cross-layer multicasting scheme based on the concept of local backtracking groups and adequate buffer equipped within nodes to avoid undesired retransmission from the source and further to improve the efficiency of source-to-receivers delivery with the aid of buffer. While encountering route failure, a node can quickly restore its routing paths to multicast subscribers by exploiting the precise notification from the MAC layer and the parent group then opportunely provides it with an unacknowledged packets conserved in the buffer. It is obviously benefic that retransmission packets are issued from the parent group rather than from the source. The authors present both analytic models and simulation results that substantiate the efficiency and robust of our approach based on realistic mobility scenarios.