TOPOSIM: WIRELESS AD HOC NETWORK TOPOLOGY SIMULATOR Trajanov Dimitar 1 , Mickova Borkica 2 , Filiposka Sonja 1 , Aksenti Grnarov 1 1 e-Technology Center, Faculty of Electrical Engineering, Ss. Cyril and Methodius University, Karpos 2 bb., PO Box 574, 1000 Skopje, R. Macedonia {mite, filipos, grnarov} @etf.ukim.edu.mk 2 MTnet, Orce Nikolov b.b., 1000 Skopje, R. Macedonia borkica.mickova@mt.net.mk Keywords: ad hoc networks, topology characteristics, simulation, simulator Abstract: An important task of an ad hoc network consisting of geographically dispersed nodes is to determine the characteristics of the topology which include connectivity, energy-effectiveness, throughput, and robustness to mobility. However, the widely used network simulators don’t support topology simulations that result in an evaluation of the quality of the network topology. Thus, in this paper, we introduce a newly developed wireless ad hoc network topology simulator – TopoSim, that can be used for the purposes of simulating a topology of an ad hoc network, including its dynamical changes caused by the node’s mobility, for the purposes of determining the main topology characteristics of the simulated network. 1 Introduction Although one of the original motivations for ad hoc networks found in military applications still dominate the research needs in ad hoc networking, the recent rapid advent of mobile telephony and plethora of personal digital assistants has brought to the fore a number of potential commercial applications of ad hoc networks. An ad hoc network is a collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration [2]. The mobile nodes in the network dynamically establish routing among themselves to form their own network “on the fly”. Due to the limited transmission range of wireless network interfaces, multiple network "hops" may be needed for one node to exchange data with another across the network, while each mobile node operates not only as a host but also as a router, forwarding packets for other mobile nodes in the network. An important task of an ad hoc network consisting of geographically dispersed nodes is to determine the characteristics of the topology. The quality of the topology can be evaluated according to several criteria including connectivity, energy-efficiency, throughput and robustness to mobility [4]. Since the topology characteristics are one of the most important factors affecting the network efficiency, it’s important to supply