Identification of Critical Node for the Efficient Performance in Manet

This paper considers a network where nodes are connected randomly and can fail at random times. The critical- node test detects nodes, whose failures are malicious behavior, disconnects or significantly degrades the performance of the network. The critical node is an element, position or control entity whose disruption, is immediately degrades the ability of a force to command, control or effectively conducts combat operations. If a node is critical node, then more attention must be paid to it to avoid its failure or removal of a network. So how to confirm critical nodes in the ad hoc network is the premise to predict the network partition. A critical node is the most important node within the entity of a network. This paper suggests methods that find the critical nodes of a network based on residual battery power, reliability, bandwidth, availability and service traffic type. The metrics for evaluation has been considered as packet delivery ratio, end-to-end delay and throughput. Nodes in Mobile Ad hoc Networks (MANETs) are battery powered and hence have limited lifetime. Due to excessive utilization a node may die which can result in energy depletion problem and thereby affect overall network performance. Local rate of energy consumption based on application can be monitored. Thus early detection and avoidance of energy depletion problem is possible based on monitoring of power and remaining battery lifetime. As and when the rate of consumption based on the application returns to efficient levels, the mobile relay is released so that it can be made available for other critical nodes. This technique can be applied to any protocol used in MANETs such as DSDV, DSR, AODV, TORA etc. In this work, we focus on maximizing avoidance of network partition, rather than after the network partition, then taking some remedial measures. We describe the critical nodes compensation approach to increase the network connectivity and improve packet delivery rate. First, we detect the critical nodes which may lead to the network partitioning. Secondly, propose the compensation algorithm to avoid the network partitioning. This approach described in this paper is built around the notion of a critical node in an ad hoc network. Our definition of a critical node is a node, whose failure or malicious behavior disconnects or significantly degrades the performance of the network. Once identified, a critical node can be monitored in terms of resource. If a node is not considered critical, this metric can be used to decide if the application or the risk environment warrant the expenditure of the additional resources required to monitor, diagnose, and alert other nodes about the problem. Determining the global network topology in a MANET gives the time delays of the diagnostic packets and the mobility of the nodes makes this task futile, but determining an approximation of this topology or subset of this topology, within a certain time frame may be useful. An approximation of the network topology can still provide useful information about network the density, network mobility, critical paths, and critical nodes. Even with the uncertainty associated with correctly reconstructing the network topology for a given time period, this additional information can help to reduce the resources consumed to monitor all nodes in the absence of this information.