In wireless and distributed nature of Ad hoc networks, security has become a more sophisticated problem than security in other networks, due to open nature and lack of infrastructure of such networks. This book is based on Black Hole attack. This attack node first invades into the multicast forwarding group. It then absorbs all the data packets in the network and drops fully or partially in such a way that the destination node does not get the data packets fully. This will affect the packet delivery ratio (PDR). Our aim is to draw the graph based on the black hole attack position in the network. With respect to the attack positions, black hole node at near receiver area is the least harmful attack. The PDR resulting from this position is always higher than the other two areas. Black hole node at near sender area is the most damaging attack position and incurs the lowest PDR. Finally, the anywhere area offers higher PDR than the near sender but lower than the near receiver.