2nd National Conference on Information and Communication Technology (NCICT) 2011 Proceedings published in International Journal of Computer Applications® (IJCA) 1 Performance Evaluation of AODV protocol in MANET using NS2 Simulator Nisarg Gandhewar MTech II Year Deptt of CSE RCERT Chandrapur Rahila Patel Assistant Professor Deptt of CSE RCERT Chandrapur ABSTRACT The widespread use of mobile and handheld devices is likely to popularize ad hoc networks, which do not re-quire any wired infrastructure for intercommunication, in which each node can move in any direction & acts as a router. To assist communication in such network, a routing protocol is vital whose primary aspiration is to set up proficient route among pair of nodes, due to this lot of reactive, proactive & hybrid routing protocols have been proposed, Out of which one of most popular one is Adhoc on-demand distance vector routing (AODV) due to its high performance gain compared to other protocols in MANET, therefore its performance needs to be evaluated by making use of various metrics such as end to end delay, packet delivery ratio (PDR) & Packet loss. So this paper presents simulation result obtained in the form of variations in the values of end to end delay, packet delivery ratio(PDR) & Packet loss for AODV when we vary number of nodes in network, simulation is carried out using widely use simulator NS2, also this paper provides overview of working, features & benefits of AODV compared to others protocols. Keywords MANET, AODV, Proactive, Reactive, PDR, NS2. 1. INTRODUCTION MANET is one of self configuring fastest emerging, due to commencement of economical, small & more powerful wireless devices. It is being used in most of applications, ranging from military to civilian, where each node acts as router. To facilitate communication in adhoc network, a routing protocol is vital whose primary goal is to establish accurate & efficient route between pair of nodes, due to this lot of routing protocols have been proposed for MANET & its success depends on people’s confidence in its security. The routing protocols mainly classified into three major categories proactive, reactive & hybrid. Proactive protocols continuously learns topology of the network by exchanging topological information among network nodes, where each node builds its own routing table which it can be use to find path to destination. If the network topology changes too frequently, the cost of maintaining network might be very high. DSDV, OLSR, CGSR belongs to this category. In reactive routing nodes do not exchange any routing information. A source node obtains path to specific destination only when it needs to send some data to it. AODV, DSR CBRP are some example of this category. Hybrid routing protocols is a combination of both reactive & proactive routing protocols. ADV, ZRP will represent this category [3]. Out of this AODV is a very simple, efficient, and effective routing protocol which is use mostly. This algorithm was motivated by the limited bandwidth that is available in the media that are used for wireless communications. Obtaining the routes purely on-demand makes AODV a very useful and desired algorithm for MANETs. The routing protocols for ad hoc wireless network should be capable to handle a very large number of hosts with limited resources, such as bandwidth and energy. The main challenge for the routing protocols is that they must also deal with host mobility, meaning that hosts can appear and disappear in various locations. Thus, all hosts of the ad hoc network act as routers and must participate in the route discovery and maintenance of the routes to the other hosts. For ad hoc routing protocols it is essential to reduce routing messages overhead despite the increasing number of hosts and their mobility. Keeping the routing table small is another important issue, because the increase of the routing table will affect the control packets sent in the network and this in turn will affect large link overheads. The performance of any routing protocol can be realized quantitatively by means of various performance metrics such as PDR packet delivery ratio, end to end delay & packet loss. Simulation result can be obtained by varying number of nodes in the network by using simulator NS2 [1]. The rest of the paper is organized as follows: Section 2 presents overview of AODV protocol describing its working, while section 3 describe evaluation criteria to be consider to evaluate performance of AODV, Where as section 4 depicts simulation model use, while section 5 describes results & its analysis where as section 6 concludes this paper & finally section 7 presents our future work. 2. OVERVIEW OF AODV AODV is motivated by limited bandwidth that is available in the media that are used for wireless communications is essentially a combination of both DSR and DSDV. It borrows the basic on-demand mechanism of route discovery and route maintenance from DSR, plus the use of hop-by-hop routing, sequence numbers, and periodic update packets from DSDV. The main benefit of AODV over DSR is the source route does not need to be included with each packet. This results in a reduction of routing protocol overhead. Unfortunately, AODV requires periodic updates which consume more bandwidth than is saved from not including source route information in the packets. AODV discovers a route through network wide broadcasting. The source host starts a route discovery by broadcasting a route request to its neighbors [5]. When a node wants to send a packet to some destination node and does not have a valid route in its routing table for that destination, it initiates a route discovery process. It is describe in detail as follow [2]. 2.1 Control Messages in AODV There are four control messages are used by AODV described as below