Reliability and achieving robustness is a great challenge in wireless Mobile Ad-hoc NETworks (MANETs). Implementation of multicast routing in MANETs poses several setbacks in achieving high degree of throughput. This paper proposes a Reliable Channel Aware RDMP for mobile ad hoc networks by which reliability and robustness is achieved. Due to increasing group size and limited bandwidth constraint in MANETs, Multicast routing is prone to link failure that results in a loss in packet transmission and subsequently greater impact on throughput. In this paper, multicast group is formed with respect to Virtual Reference Point (VRP) and optimum contention window is created using truncated exponential back off slot time based on counting number of collisions.