Samiti Gupta et al, International Journal of Computer Science and Mobile Computing, Vol.3 Issue.4, April- 2014, pg. 771-779 © 2014, IJCSMC All Rights Reserved 771 Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology ISSN 2320–088X IJCSMC, Vol. 3, Issue. 4, April 2014, pg.771 – 779 RESEARCH ARTICLE A Comparative Analysis of OLSR, DSR and ZRP Routing Protocols in MANETs 1 Er. Samiti Gupta, 2 Er. Naveen Bilandi 1 Research Scholar, Computer Science & Engineering, DAV University, Jalandhar, Punjab (INDIA) samitigupta@gmail.com 2 Assistant Professor, Computer Science & Engineering, DAV University, Jalandhar, Punjab (INDIA) naveenbilandi77@gmail.com Abstract — A Mobile Ad-Hoc networks (MANETs) is collection of autonomous wireless nodes that are arbitrarily located which move dynamically by changing its network connectivity without the use of any pre-existent infrastructure. The behavior of ad-hoc network is characterized as non-deterministic (interference, multipath, hidden and exposed node problem make wireless channel very difficult to predict). Its routing protocol should not only capable of finding the optimized routes between the source and destination, but should also be adaptive in terms of changing load conditions of the network, changing state of the nodes and changing state of the environment. This paper aims to compare performance of Dynamic Source Routing (DSR), Optimized Link State Routing Protocol (OLSR) and Zone Routing Protocol (ZRP). The performance analysis is based on different network metrics in heterogeneous environment such as Throughput (bits/sec), Delay (sec) and Retransmission attempts (packets) using well known network simulator OPNET 14.5. Keywords – MANET, ZRP, OLSR, DSR I. INTRODUCTION A MANET is a multi hop ad-hoc wireless network and self configuring network of mobile routers connected by wireless links (sometimes called a Mobile Mesh Network) the union of which forms an arbitrary topology. Interest in MANETs is due to the promise of ubiquitous connectivity beyond that currently being provided by the Internet. Firstly, MANETs are easily deployed allowing a plug-and-communicate method of networking. Secondly, MANETs do not need central management so used in military operations where units are moving around the battle field and a central field cannot be used for synchronization [1]. Thirdly, MANETs need no infrastructure, thus reducing the cost of establishing the network so useful in disaster recovery where there is not enough time or resources to install and configure an infrastructure. The growth of technology and the increase in wi-fi capable laptops, mobile phones, MP3 players and other small portable devices has created a genuine reason for the population of MANET [2]. Nodes in MANET are free to travel, and the connection between two nodes is broken when one of them travels out of the transmission range of the other node [3]. In ad-hoc networks, nodes do not start out familiar with the topology of their networks; instead they have to discover it. The basic idea is that each node learns about nodes nearby and static ad- hoc network the positions of a node may not change once it has become a part of the network. E.g.: Rooftop networks. Highly mobile nodes are characterized by limited memory, bandwidth and power and also causing a high rate of change of connectivity within the network. The primary challenge in building a MANET is equipping each device to