International Journal of Computer Applications (0975 – 8887) Volume 166 – No.12, May 2017 24 Performance Investigation of Single Path and Multi Path Routing Protocols in High Mobility MANETs Suveg Moudgil PhD Research Scholar, CSE Dept. MMEC, M.M. University, Mullana Sanjeev Rana, PhD Professor, CSE Dept. M.M. University, Mullana ABSTRACT Mobile ad hoc networks are the collection of wireless nodes which communicate with each other without the support of centralized infrastructure. Due to frequent node mobility in high mobility MANETs, the network topology changes dynamically. Each node in MANET acts as host and router. A routing protocol is used to discover route between nodes. Robust routing protocol is needed to allow the nodes to communicate in high mobility MANETs. This paper investigates the performance of single path routing protocol AODV and multipath routing protocol AOMDV under different mobility conditions. Performance evaluation of these protocols showed that AOMDV protocol is more robust than AODV protocol due to its capability of finding and using alternate routes in case of a route failure in high mobility MANETs. Keywords AODV, AOMDV, Multipath Routing, Robust Routing. 1. INTRODUCTION Mobile ad hoc networks are the networks which consist of mobile nodes that can communicate with each other without any fixed or predetermined infrastructure [1]. MANETs have the unique characteristics which include dynamic topology, bandwidth constrained links and limited energy of nodes [2]. Ad hoc networks can be applied anywhere at any time without infrastructure. Example applications o ad hoc networks includes military battlefield, emergency search and rescue operations, meeting and conventions in which a person want to make a quick connection for information sharing. Routing protocols have a significant role in enabling communication in wireless ad hoc networks. Routing protocols can be classified as proactive, reactive and hybrid protocols [3]. Proactive or Table driven routing protocols keep up-to-date routing information in a routing table which is exchanged periodically or when network topology changes. Optimized link state routing (OLSR) [4] and destination sequenced distance vector (DSDV) [5] are well known proactive routing protocols. Reactive or on demand routing protocols creates route to the destination only when required. Examples of on demand routing protocols includes AODV [6], DSR [7] and TORA [8]. Hybrid routing protocols provides the benefits of proactive and reactive routing protocols. Zone routing protocol (ZRP) [9], Zone based hierarchical link state (ZHLS) [10] and Core extraction distributed ad hoc routing (CEDAR) [11] are examples of hybrid routing protocols. A robust routing protocol is required to provide reliability and energy efficiency with low control overhead. The wireless medium dynamic nature, fast and unpredictable topological changes, limited battery power and mobility of nodes puts challenges in designing of the robust routing protocols. The routing protocols are classified in to two categories based on the no. of paths used between any source-destination pair. These are single path or uni-path routing protocol and multipath routing protocols. Multipath routing protocols finds multiple paths between any source-destination pair. This paper investigates the performance of single path routing protocol AODV and multipath routing protocol AOMDV under different mobility conditions. We have evaluated the Performance of these protocols on the basis of different parameters which includes packet delivery ratio, average end to end delay and normalized routing overhead. Rest of the paper is organized as follows. Section II gives brief background of single path and multipath routing protocols. Section III describes the simulation model and parameters. In Section IV, results are compared and analyzed. Section V presents the conclusion of the paper. 2.1 LITERATURE REVIEW 2.1.1. Single Path Routing Protocols The single path routing protocols finds only a single path route between a source-destination pair [13]. A new route discovery is required in case of every route break. Single path routing protocols have route discovery and route maintenance phase. In route discovery phase a route is find out between any source-destination pair. Route maintenance phase consist of repairing a broken route or finding a new route in the presence of a route failure. The most common single path routing protocols are AODV [5], DSR [6] and DSDV [4] etc. 2.1.2 AODV The Ad hoc On-Demand Distance Vector Routing (AODV) protocol is a reactive unicast routing protocol for MANETs. [6] [12] AODV maintains the routing information of active paths in routing tables at nodes. Each mobile node maintains a next hop routing table, which contains the destinations to which it currently has a route. AODV uses destination sequence number technique for ensuring loop freedom. In AODV, when a source node wants to send packets to the destination it checks its routing table for active routes to the destination. If no route is available, the source node initiates a route discovery procedure. In route discovery procedure, the source node broadcasts route request (RREQ) packets. The RREQ packet consist of source address, destination address, broadcast id, last seen sequence number of the destination and source node sequence number. Sequence numbers are essential to assure loop free and up-to-date routes. A route can be established when the RREQ reaches either the destination itself or an intermediate node with a fresh enough route to the destination. The intermediate nodes discards RREQs that it has seen before to reduce the flooding overhead. A route is selected with the highest destination sequence number in case of choice between multiple routes to the destination. The route is made available by unicasting the Route Reply RREP packet