ISSN: 2277–3061 (online) International Journal of Computers & Technology Volume 2 No. 3, June, 2012 92 | Page www.inctonline.com SR-AODV: A Stable Route-AODV Protocol for Mobile Ad hoc Network Pratima Gupta Madan Mohan Malviya Engineering College, Gorakhpur Dr. Rakesh Kumar Madan Mohan Malviya Engineering College, Gorakhpur ABSTRACT Mobile ad-hoc network is the collection of node which dynamically forms a temporary network without the use of any existing network infrastructure or centralized administration. When the mobility in the network is high and the topology changes frequently the route maintenance overhead in AODV increases. Because nodes can move link breakages can occurs. Long path is more vulnerable to link breakages and requires high control overhead for its maintenance. In this paper we introduce a new modified AODV protocol. This new protocol uses stability factor of intermediate nodes to find the most sable neighbors and therefore most stable path. This new proposed protocol is SR- AODV (Stable Route AODV) protocol. We simulate both AODV and SR-AODV with ns-2 in similar scenario. We find that SR-AODV will show better performance than AODV. Keywords AODV, Stable Route AODV, Stability Factor, Link Breakage 1. INTRODUCTION The movement of the nodes affects the interconnected path of the mobile Ad-Hoc network, which in turns affect the performance of the networks. We have studied the impact of the node density of the SR-AODV & AODV. The number of the possible connection between any two nodes is very less in sparsely populated network. So, the performance of the overall network is being poor. It is expected in the SR-AODV, when node density is increased the throughput of the network is also being increased. But after the certain level if density of the node is increased, the performance of the network decreases in some protocol. For the reliable path, selection of optimal path is one strategy through which data packets can be transmitted. There are many paths which are based on shortest path, stable path and signal quality based routes. The main challenge of these MANETs routing protocol is to provide a stable and reliable communication platform against the face of widely changing and highly mobile network. During the past time, researcher have given number of protocols AODV, DSR, DSDV, TORA are emerging routing protocols of IETF MANETs working group [1] [2] [3]. In performance comparison between conventional AODV and modified AODV protocol, modified AODV shows good performance in case of packet delivery fraction and average end to end delay, which are the most important metrics. In this paper, we have modify the conventional AODV and proposed SR-AODV (Stable Route-AODV) protocol which is based on the concept of “path stability”. In this work, our main goal is to modify the conventional AODV protocol so that selection of routing path would be stable. Selection of more stable path, minimize the number of link/path breakages and SR-AODV performers better in highly mobile network. 2. RELATED WORK Many researchers have given significant contribution to the modification of AODV protocol in Ad hoc wireless communication. They have modified conventional AODV routing protocol to increase the performance of Ad hoc networks. AODV has been extensively investigated and a number of optimizations / modifications have been suggested: Modified/Optimized AODV Protocols IAODV EAODV OAODV AOMDV LS- AOMDV Fig.2.1: Modifications/Optimizations to AODV Protocols AODV protocol can be implemented and evaluated for different mobility models like Random Waypoint (RWP), Reference Point Group mobility (RPGM) and Gauss Markov models (GMM) [4] and it can be shown that AODV protocol with RPGM model has optimized results for varying network load and speed. In AODV, each node has certain lifetime. If it expires, rebroadcasting of RREQ is done. In [5], Z. Jianwu et al. proposed improved AODV routing protocol (IAODV) which controls the rebroadcasting of RREQ by measuring node lifetime when sending RREQ information. Thus IAODV controlled the sending of packet more efficiently which results in better packet delivery ratio and routing load parameter. In [6], authors have proposed an enhanced AODV protocol (EAODV). In this scheme, mobile nodes are made more aware of the local connectivity to their neighbors. This is done by extending the original HELLO message in AODV but with lower overhead. Moreover, it can prevent the potential unidirectional links in the network which caused unnecessary loss of data packets. Due to node’s mobility and limited transmission range, the routes created by original AODV become invalid frequently which results in large control overhead. Hence, in [7] authors have suggested optimized AODV (OAODV) based on the concept of reliable distance. This reliable distance (r) which is always less than transmission range (R) depends on node’s velocity and direction which are obtained from GPS. r decides whether the node can receive RREQ from its neighbor. Thus region of flooding RREQ is restricted. By using this scheme the routes are made more reliable. A multi-path, loop free extension to AODV has been proposed in [8], which is called ad-hoc on demand multi-path distance vector routing (AOMDV). It ensures that alternate paths at every node are disjoint. Based on AOMDV, a multi-path routing protocol for real-time video transport which is called link stability-aware AOMDV (LS- AOMDV) has been proposed in [9]. 3. AODV PROTOCOL Ad-hoc On-Demand Distance Vector Routing Protocol (AODV) that uses a demand-driven route establishment procedure. The Ad-hoc On-Demand Distance Vector outing Protocol (AODV) [3], is one of more common routing protocol in ad hoc networks and is based on the principle of discover routes as needed. AODV is a reactive protocol that has some capabilities such as; low processing, memory overhead, low network utilization. AODV routing algorithm