unicast routing protocols-2

unicast routing protocols-2

An effective localized route-repair algorithm for use with unicast routing protocols for mobile ad hoc networks

FREE DOWNLOADN Meghanathan : International Journal of Computer and Network ,2009 : ABSTRACT We propose an efficient and effective Localized Route Repair (LRR) algorithm that would minimize the number of flooding-based route discoveries for on-demand unicast routing protocols in Mobile Ad hoc Networks (MANETs). The principle behind the LRR algorithm A mobile ad hoc network (MANET) is a distributed dynamic system of autonomously moving wireless devices (nodes). The wireless nodes self-organize themselves for a limited period of time depending on the application and the environment. As the nodes are battery-charged and recharging is next to impossible, the transmission range (i.e., the communication range) of the nodes is often limited. As a result, it may not be always possible to have point-topoint direct communication between any two nodes. A wireless link is said to exist between two nodes only if the two nodes are within the transmission range of each other. Communication sessions in MANETs are often multi-hop in nature, involving intermediate peer nodes that cooperatively forward data packets from the source towards the destination. As the topology changes dynamically, routes between the source and destination nodes of a communication session have to be frequently reconfigured in order to continue the session. MANET routing protocols are of two types: Proactive and Reactive. Proactive routing protocols tend to maintain routes between any pair of nodes all the time; while reactive routing protocols discover routes from the source to destination only on-demand (i.e., only when required). In a dynamically changing environment (like that of battlefields), reactive routing has been preferred over proactive routing as the latter involves considerable route maintenance overhead . In this paper, we restrict ourselves to exploring the reactive routing strategy. On-demand route discovery in reactive routing protocols is often accomplished through a global flooding process in which each node will be involved in forwarding (transmitting and receiving) the route discovery message from the source towards the destination. Frequent flooding based route discoveries can quickly exhaust the battery charge at the nodes and also consume the network capacity (bandwidth). Several on-demand routing protocols have been published in the literature [3], each with a particular route selection metric. The most commonly used route selection metric is the hop count. Routes with the minimum hop count are preferred because the data would go through the minimum number of intermediate forwarding nodes, resulting in lower end-to-end delay and reduced energy consumption per data packet transferred. But, it has been identified that minimum hop routes are not very stable (i.e., the routes do not exist for a long time) [4] and routes have to be frequently determined through the flooding-based route discovery procedure. In this paper, we propose a Localized Route-Repair (LRR) algorithm that would minimize the number of floodingbased route discoveries for on-demand MANET routing protocols. With the incorporation of the proposed LRR algorithm in its route management module, a unicast routing protocol would have to opt for a flooding-based route discovery only when the MANET is temporarily disconnected and a new route has to be determined between the source and destination. Otherwise, if the MANET is connected, the proposed LRR algorithm will help to fix a broken route without going through network-wide flooding of the Route Request (RREQ) messages and without requiring the intermediate nodes to determine the route all the way to the destination.


Unicast and Multicast Routing Protocols

from unicast to multicast routing CSE PROJECTS