Mobile Adhoc Network (MANET) is vulnerable to many security issues and network attacks. We presented the comparison of three different routing protocols (AODV, DSR and DSDV) on the basis of different parameters. In this paper, black hole attack is implemented on AODV protocol which reduce the performance parameters of network by exploiting the packet sequence number included in any packet header. The proposed mechanism of Intrusion Detection System (IDS) is also implemented to enhance the network performance. Simulation results using Network Simulator 2(NS2) shows that, in a high mobility environment, malicious node could be detected and the packet delivery ratio has been improved.