Application clarifying basics of operations of communication protocols

The diploma thesis aimed at the study of the topic of communication protocols and several transmission modes, as well as ARQ (Automatic Repeat Request) mechanisms. Subsequently, the task was to design and describe individual scenarios for their simulation. As a part of solving the mentioned task, it was necessary to create an application that allows the emulation of the behaviour of communication protocols without the need for a transmission in the real network a nd the requirements for the edition of the source code. The application was created in the Microsoft Visual Studio 2017 development environment using the C# programming language and .NET framework and it consists of a library and a graphical interface. The output of the solution is the application of a mode simulator of the data transmission in the network with two scenarios with the prepared input situations in the frame of graphical environment together with instructions, additional tasks and sample solutions. The program allows the simulation of the behaviour of communication protocols between the client and the server without the need for a transmission in a real network. In conclusion, the simulator of data transfer was created in the form of the desktop application which contains two scenarios. The first scenario is used to simulate ARQ mechanisms and the second one is active in the simulation of commutation of messages, circuits, packets or cells