ISSN (Print): 2319 - 2526, Volume-2, Issue - 6, 2013 36 PERFORMANCE EVALUATION OF AODV AND AOMDV ROUTING PROTOCOLS IN WIRELESS MESH NETWORK Rajesh SL, Somashekar C Desai & Ramakrishna KT Computer Science and Engineering Department JJT University, Rajasthan, India Computer Science and Engineering Department, SKSEM, Bangalore, India E-mail : samsirajesh@gmail.com, desaisc07@gmail.com, ramkrishna.appu@gmail.com Abstract - Wireless Mesh Networks (WMNs) are a radio- based network technology that has gained considerable importance in network research community. It is a multi- hop wireless access network where nodes can act both as a host as well as a router. One of the factors that influence the performance of WMNs is the underlying routing protocol used. Thus, numbers of different routing protocols are proposed in recent years. There is a need to understand the versatile behavioral aspects of these routing protocols in a wireless mesh network with varying traffic loads, the number of sources and speed. In this paper, we compare and evaluate the performance of Ad-hoc On demand Distance Vector (AODV) protocol which is unicast protocol with Ad-hoc On-demand Multipath Distance Vector (AOMDV) protocol, which is multipath routing protocol. The performance differentials are analyzed using metrics such as end to end delay, packet delivery ratio and normalized routing overhead. Index Terms— WMN, AODV, AOMDV, Routing Protocol, NS2. I. INTRODUCTION Wireless Mesh Networks (WMNs) [1] are an emerging technology and are making significant progress in the field of wireless networks in recent years. Mesh networks are capable of rapid deployment and reconfiguration and this gives advantages like low up- front cost, simplicity of setting up a network, easy network maintenance, broadband capability and reliable service coverage. Typically WMNs consist of mesh routers and mesh clients where each node can operate both as host and router. Mesh routers generally have minimal mobility in a mesh network and form the backbone of WMNs. The clients could be either stationary or mobile and can form self organized ad hoc networks which can access services by relaying requests to wireless backbone network. Routing in mesh networks is challenging, since the radio environment is hostile and unstable, and limited by interference, with new performance issues. So, many routing protocols have been proposed in literature by considering the characteristics of WMN. The main body of routing protocol proposals regards single path routing, i.e., for each source-destination pair a single (shortest) path is discovered and used for data transmission [2]. An alternative is multi-path routing ([3, 4, 5]) in which multiple paths are used, thereby offering more opportunities for regulating the traffic over the network. Multi-path routing enhances single-path routing mainly in two directions: (i) to have backup paths available in case of path failures and (ii) to spread traffic to increase the effective bandwidth so that packet delivery ratio is good. However, there are also a number of drawbacks to employing multiple paths. In single-path routing the shortest path is normally selected; hence, any additional path will typically be longer. This may not matter when considering capacity questions, but it definitely does when considering the transfer time of a packet. Another drawback, which occurs typically in wireless environments, is that nodes situated on nearby paths may interfere. Therefore, the actual performance gain (in terms of bandwidth) of using multiple paths over using a single path is uncertain. In this paper, we have carried out extensive simulation study of these two types of routing protocols by varying number of nodes, traffic flows and speed. The rest of the paper is organized in the following way. Section 2 gives the overview of wireless mesh networks architecture. Section 3 describes the simulated protocols namely AODV and AOMDV. Section 4 describes the simulation tool and performance metrics used. Section 5 presents the results and discussions of study. Section 6 presents the conclusions and future works. II. OVERVIEW OF WMN ARCHITECTURE WMNs can be divided into three main types: Infrastructure, Client, and Hybrid [1]. In an Infrastructure WMN, Mesh Clients gain access to each other or to the backhaul network through Mesh Routers and are not actively involved in routing and forwarding