International Journal of Computer Applications (0975 – 8887) Volume 112 – No. 2, February 2015 1 Performance Comparision of AODV and DSR Routing Protocols using Real Time Test-Bed Dependra Dhakal, Kiran Gautam, Bishal Pradhan, Ashis Pradhan CSE Department, Sikkim Manipal Institute of Technology, East-Sikkim, India ABSTRACT A mobile ad-hoc Network is a collection of autonomous wireless nodes without any infrastructure and centralized administration. The main motivation of this work is to analyze AODV and DSR routing protocols based on different performance metrics in a real world environment. This test- bed allows for direct comparisons between ad-hoc routing protocols Though ad hoc network routing protocols, such as DSR and AODV have been extensively studied through simulations, fewer test-bed implementation has been carried out. It is essential in order to understand relative merits or limitations under different network conditions. The test-bed closes the gap between the simulation & real life implementation and allows performance comparison of different ad-hoc routing protocols on a common platform. The goal of this work has been to develop a test-bed such that real world tests of many nodes can be conducted for AODV and DSR protocol and analyze the performance of this protocol with various performance metrics. Keywords AODV, DSR, MANET, PDR, ad-hoc. 1. INTRODUCTION Ad-hoc Networks are wireless multi-hop packet networks without any fixed infrastructure. The main motive of wireless network is to maintain node connectivity in a mobile environment. Most research in the ad-hoc network wireless network has been conducted using simulation software and test bed environment. Each node in a wireless ad-hoc network functions as both as host and a router, and the control of the network are distributed among the nodes without any centralized control. The topology is in general dynamic due to mobility of nodes. Additionally, wireless mobile networks have high error rate, power restrictions and bandwidth limitation [1]. Mobile ad hoc network routing protocols can be divided into proactive, reactive and hybrid routing [17] [19] [25]. A proactive routing protocol is also called "table driven" routing protocol. Using a proactive routing protocol, nodes in a mobile ad hoc network continuously evaluate routes to all reachable nodes and attempt to maintain consistent, up-to-date routing information. The Dynamic Source Routing (DSR) and Ad hoc on-demand Distance Vector routing (AODV) are examples for reactive routing protocols for mobile ad hoc networks. AODV uses the concept of route discovery and route maintenance of DSR and the concept of sequence numbers and sending of periodic beacons from DSDV [3]. AODV uses three types of control messages. They are Route Request (RREQ), Route Reply (RREP) and Route Error (RERR) messages [5]. When a route does not exist between two nodes i.e., when a route to new destination is required it initiatesthe route discovery process. Route discovery involves flooding of RREQ messages to its neighbor to find the destination node. Route discovery process can also be initiated if the link has expired or broken. An intermediate nodereceiving theRREQ, is required to first setup a reverse path to the source node. It uses sequence number and broadcast ID for loop free routing. When the destination receives a route RREQ, It responds with a RREP message containing the number of hops and latest destination sequence number. RREP is routed back to the source node using the reverse path and forward path to the destination is established. A time to live is associated with each reverse route entry. If no packets are sent over this route within the lifetime it will be removed [19] [17] [18]. In route maintenance phase each node use hello packets to check for the link. When a link failure is detected by a node it sends a route error (RRER) messages to its upstream neighbor on the current route. These error messages propagate to the source node. Intermediate nodes receiving a RERR update their routing table. The source node after receiving RERR starts the route discovery process again [19] [17] [18]. The key feature of DSR is source routing [2] [18] [16]. The source or the sender knows the complete hop-by-hop route to the destination. These routes are stored in route cache. It uses a route discovery process to dynamically determine the unknown route. It does not use periodic hello message unlike AODV. RREQ and RRER message is used to discover the route similar to AODV. Source node broadcast the RREQ message and the receiving neighbor node adds its address to source address and rebroadcast the RREQ message if it does not have the information for destination node. If route to the destination node is known they send a route reply packet to the source node. Every node also maintains a cache to that stores the route information [16]. The advantage of DSR is that it can store multiple routes in their route cache [20]. If any link on a source route is broken, a node that identifies the break sends a route error (RERR) packet to the source node. On receiving the RERR packet source node updates its route information by removing the link from its cache. A new discovery process will be started to find the viable route [5]. The testing of ad-hoc networking protocols using test-bed allows researchers the opportunity to check the behavior of protocol in real world environment [5]. In the modern world mobility has become increasingly important and ad-hoc network routing protocols is distinguished based on how routing information is acquired and maintained by mobile nodes [3]. 2. LITERATURE REVIEW Several projects capture the performance of different ad-hoc routing algorithms [1] [4] [5] [6]. They all found that each routing algorithm can outperform the others in certain conditions, depending on the workload, network