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-Mobile ad hoc network (MANET) is now days become very famous due to their fixed infrastructure-less quality and dynamic nature. They contain a large number of nodes which are connected and communicated to each other in wireless nature. Mobile ad hoc network is a wireless technology that contains high mobility of nodes and does not depend on the background administrator for central authority, because they do not contain any infrastructure. Nodes of the MANET use radio wave for communication and having limited resources and limited computational power. The Topology of this network is changing very frequently because they are distributed in nature and selfconfigurable. Due to its wireless nature and lack of any central authority in the background, Mobile ad hoc networks are always vulnerable to some security issues and performance issues. The security imposes a huge impact on the performance of any network. Some of the security issues are black hole attack, flooding, wormhole attack etc. In this paper, we will discuss issues regarding low performance of Watchdog protocol used in the MANET and proposed an improved Watchdog mechanism, which is called by I-Watchdog protocol that overcomes the limitations of Watchdog protocol and gives high performance in terms of throughput, delay.Keywords -MANET; Watchdog; AODV; Black hole; RREP; RREQ; RRER; Malicious node; PDR; I-Watchdog; Sequence number; I. INTRODUCTION N the mid of 1990's, Mobile ad hoc network became very famous topic in the research area of networking. Mobile ad hoc network is a wireless technology and it does not hold any infrastructure; nodes in the MANET environment are dynamic in character and do not relay on any topology. They are scattered in nature and do not rely on any central authority. In a MANET, [11] each node can take responsibility of a router as well as take a role as a host. The nodes in the mobile ad hoc network are linking and Communicate with each other all the way through the usage of radio waves.[1]MANET supports fast establishing of networks so they encompass very high degree of flexibility, the only necessity is to provide a new set of nodes with some degree of wireless communication range. [17]If the nodes are within the same radio waves wireless communication rang than they can communicate directly otherwise they can communicate with their respective destination node with the help of intermediate nodes. In the above figure, many numbers of nodes are in the network, in which, one is acting as a sender node and another one is the receiving node. Sender wishes to propel data packet to his subsequent receiving node. For initiating this communication, the sender can send these data packets via the help of intermediate nodes, which are within the communication range of the sender node. By following this strategy, the sender node sends all data packets to the respective receiver node. [2]There are various types of the mobile ad hoc networks, such like, vehicular ad hoc network (VANET) [12] that is used for making the communication b...

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