Mobile ad hoc networks as an infrastructure free, and constrained resource environment network. The network aim is to establish internet connectivity everywhere regardless of location. The applications of network are healthcare,
disaster relief and military, where reliable communication is major concern. Communication in the network is initiated by establishing the communication route between source and destination and sending the information through it. One of the characteristics of MANETs is a peer-to-peer network, where intermediate nodes have to cooperate for reliable communication by acting as routers. In literature number of routing protocols have been designed based on the MANET’s peer to peer characteristic. However, it may not be every time true that the intermediate nodes act as faithful routers, and they may untrustworthy either due to malicious behavior or bottleneck. Number of secure protocols have been designed to mitigate malicious behavior by neglecting the bottleneck. The paper aims to define the bottleneck, and its importance in communication. Finally, how bottleneck influence on the MANETs performance during malicious nodes mitigation