## 4 Results: State-of-the-Art Approaches
### Simulation of Cybersecurity and Interoperability in IoUT
Aqua-Sim ([[https://github.com/rmartin5/aqua-sim-ng](https://github.com/rmartin5/aqua-sim-ng)]([https://github.com/rmartin5/aqua-sim-ng](https://github.com/rmartin5/aqua-sim-ng)), accessed on 20 November 2022), an open-source underwater simulator which supports a vast number of protocols and features, provides simulation of acoustic signals and packet collisions in UWSNs, as well as a three-dimensional deployment. This simulation tool is the most widely utilized by researchers and it is based on the famous NS-2 (Network Simulator) tool, which is written also in C++ and is highly suitable for UWSNs. Its association with a visual tool, and support of monitoring node placement, movement, and packet flow, allow users even more complex experimentation [96]. Another well-known simulation tool is SUNRISE (Sensing, Monitoring and Actuating) [97]; it is an environment-based testbed for UWSN, designed by La Sapienza University. It supports scalability and heterogeneity across various domains and real-time environments. Its main advantage over the rest of the tools is its ability to span different types of underwater environments in various locations. In addition, the SUNRISE2 SUNSET plug-in [97] allows users to simulate, emulate and test novel underwater systems (at-sea). Additionally, OMNeT++ is a very simple but effective, extensive, modular simulation library and framework for building network simulators. It provides an excellent programming guide and has a library of simulation classes [98]. Numerous and various protocols are supported and provide a GUI (graphical user interface) for execution. The UDMSim simulation platform was developed to support a data mulling-oriented solution. This tool merges the AUV Motion and Localization (AML) simulator and NS-3 [99] and is capable of reproducing realistic scenarios with localization errors and providing evaluation of underwater communications, by simulating the signal and connection losses during an operation. GloMoSim (global mobile information system simulator) is another simulation tool which provides scalability to networks with a vast number of heterogeneous devices. It supports a vast number of networking protocols, both for wired and wireless networks. The main disadvantages of this tool are the poor documentation, and its rare updates. Lightweight simulation and detailed visualization are two main advantages of TOSSIM ([[https://networksimulationtools.com/tossim-in-wsn/](https://networksimulationtools.com/tossim-in-wsn/)]([https://networksimulationtools.com/tossim-in-wsn/](https://networksimulationtools.com/tossim-in-wsn/)), accessed on 20 November 2022), a discrete event simulator. It provides a powerful GUI and supports a wide range of network interactions. Furthermore, it provides a simple yet mighty emulator for WSNs (wireless sensor networks). While TOSSIM can be utilized for fast and representative results, its lack of accuracy in real-world results and several self-made assumptions of this tool, can be important deterrents for its selection. Routing schemes in communication can be very complex. Finally, a network emulation software which provides huge capabilities and realistic environment to network and security professionals is EVE-NG (emulated virtual environment next generation, [[https://www.eve-ng.net/](https://www.eve-ng.net/)]([https://www.eve-ng.net/](https://www.eve-ng.net/)), accessed on 20 November 2022). It supports cloud networking and over 1000 nodes per simulation. In addition, it allows users to extract information about the quality bandwidth, delay, jitter, and loss characteristics of communications. Table 3 presents general information of the experimented simulation tools and Table 4 provides their comparison based on specific features. As presented in this review, security is linked to interoperability, and therefore we should be able to simulate both types of issues in an underwater network.