A clustered response mechanism to discover the topology of wireless sensor networks with an application to network management at faulty and operational state of nodes

To efficiently manage the sensor networks the topology of the entire network has to be discovered by the monitoring node. In this paper a topology discovery algorithm for sensor networks has been described. The algorithm finds a set of distinguished nodes, using whose neighborhood information the approximate topology of the network is constructed. Only these distinguished nodes reply back to the topology discovery probes. These nodes logically organize the network in the form of clusters comprising nodes in their neighborhood. Topology discovery algorithms form a tree of clusters rooted at the monitoring node, which initiates the topology discovery process. This organization is used for efficient data dissemination and aggregation, duty cycle assignment and fault tolerance of the network system. The unpredictable behaviors of sensor networks have made it a vital point that how the operational nodes will be managed when a node in the network fails. In this paper fault tolerance mechanisms for sensor networks have been described for clustered response approach on considering different scenarios that may come to consideration when a node fails; thus ensuring maximum connectivity among operational nodes after the failure of the node. The mechanism explains how the information packets transmitted to the faulty node can be cached by an operational node. After being repaired the faulty node is reinstalled to operational state and the mechanisms of getting the repaired node connected to the network have been described in this paper. Reverse traverse mechanism has been described in this paper as a part of fault tolerance mechanisms, which ensures that the number of clusters is not increased when a faulty node is repaired and re-connected to the network. The mechanisms described in this paper are distributed and highly scalable.