AN APU BASED UPDATION SCHEME WITH ADDED SECURITY MEASURES

Routing with the use of location information has become one of the most suitable routing strategies in wireless mobile ad hoc network mainly due to its scalability.  Position information of the nodes is primary requirement in geographic routing.  Nodes for forwarding are selected among neighbors based on their location. Each node in the network should be aware of its neighbor’s location in order to maintain the accuracy of local topology. Hence updation of location information through beacon is necessary. Existing mechanisms invokes periodic beacon update scheme which in turn consumes the network resources specifically when the network traffic is high it leads to packet loss and at times causes retransmission of data packet  .In this work, adaptive position update is proposed which dynamically adjusts the beacon updation frequency according to the varying network conditions. APU is based on two simple principles nodes which moves with greater speed and nodes closer to forwarding paths update their positions more frequently (and vice versa)

GSAR: Greedy Stand-Alone Position-Based Routing protocol to avoid hole problem occurance in Mobile Ad Hoc Networks

The routing process in a Mobile Ad Hoc Network (MANET) poses critical challenges because of its features such as frequent topology changes and resource limitations. Hence, designing a reliable and dynamic routing protocol that satisfies MANET requirements is highly demanded. The Greedy Forwarding Strategy (GFS) has been the most used strategy in position-based routing protocols. The GFS algorithm was designed as a high-performance protocol that adopts hop count in soliciting shortest path. However, the GFS does not consider MANET needs and is therefore insufficient in computing reliable routes. Hence, this study aims to improve the existing GFS by transforming it into a dynamic stand-alone routing protocol that responds swiftly to MANET needs, and provides reliable routes among the communicating nodes. To achieve the aim, two mechanisms were proposed as extensions to the current GFS, namely the Dynamic Beaconing Updates Mechanism (DBUM) and the Dynamic and Reactive Reliability Estimation with Selective Metrics Mechanism (DRESM). The DBUM algorithm is mainly responsible for providing a node with up-to-date status information about its neighbours. The DRESM algorithm is responsible for making forwarding decisions based on multiple routing metrics. Both mechanisms were integrated into the conventional GFS to form Greedy Stand-Alone Routing (GSAR) protocol. Evaluations of GSAR were performed using network simulator Ns2 based upon a defined set of performance metrics, scenarios and topologies. The results demonstrate that GSAR eliminates recovery mode mechanism in GFS and consequently improve overall network performance. Under various mobility conditions, GSAR avoids hole problem by about 87% and 79% over Greedy Perimeter Stateless Routing and Position-based Opportunistic Routing Protocol respectively. Therefore, the GSAR protocol is a reasonable alternative to position-based unicast routing protocol in MANET