# Moving Ad Hoc Networks--A Comparative Study
## 8 Simulation Tools for Ad Hoc Network  
An ad hoc network is a multi-hop temporary non-central network composed of a group of mobile nodes with wireless communication transceivers. It can quickly build a mobile communication network at any time and any place and does not require an existing information base with the support of network facilities; each terminal in the network can move freely with equal status. As one of the core technologies of the next-generation network, the ad hoc network is widely used in military applications, civil search and rescue, industrial surveillance, mobile commerce, and other fields. Because of its special characteristics, it has become a hot issue in the fields of computers and communication. However, Table 11 shows the simulation tools for varied ad hoc networks. Network simulation technology is a necessary and effective tool for researchers in network planning and design. Network Simulation is the use of computer technology to construct the network topology and implement network protocols to simulate network behavior. It is a technique between experiment and calculation. It establishes a mathematical model of the actual system and simulates the dynamic behavior of the physical system according to the same operating mechanism. It can obtain specific network characteristic parameters and can then study and analyze the network performance to achieve the purpose of improving the network operation status. NS is an open-source discrete event-driven network simulator. NS-2 is an object-oriented, discrete event-driven network environment simulator, which is mainly used to solve network research problems. NS-2 provides a simulation of multiple protocols such as TCP, routing, and multicast on wireless or wired networks. NS-2 is implemented by two programming languages: OTCL (a TCL scripting programming language with object-oriented features) and C++. NS-3 is a discrete-event network simulator for Internet systems, targeted primarily for research and educational use. ns-3 is free software, licensed under the GNU GPLv2 license, and is publicly available for research and development use. The optimized Network Engineering Tool (OPNET) is the product of the American MIL3 company. OPNET uses a discrete event-driven simulation mechanism, where \"event\" refers to the change of the network state, and the simulator can only work when the network state changes. Objective Modular Network Testbed in C++ (OMNET++) is a software intended to build a wireless ad hoc network simulation platform. Through the study of the operating mechanism of OMNET++ simulation software, a mobile framework was installed based on the simulation platform to build a wireless ad hoc network simulation platform. SUMO \"Simulation of Urban Mobility\" is an open-source, microscopic, multi-modal traffic simulation. It allows us to simulate the way in which a given traffic demand composed of a single-vehicle/UAV moves in a given road network. GloMoSim (Global Mobile Information System) simulation software was developed by the Computer Department of UCLA University in the United States. The design of the parallel simulation language Parsec, based on the C language, can realize the parallel discrete-time drive simulation with scalability and programmability. This supports pure wireless network protocols, and the result data can be expressed in text or graphics. Using a layered approach, standard APIs are used to communicate between different layers, which implements the basic protocol stack level required by the network. QualNet is a high-performance network simulation system that can predict the performance of wireless networks, wired networks, and hybrid networks and equipment. QualNet can simulate a real wireless network in a \"software virtual network\" at a real-time speed. QualNet has multi-threaded processing capabilities, supports multi-core 64-bit processors, and can simulate a network of thousands of nodes.