The aim of the course is to acquaint students with the operating principles of various currently used and forward-looking wired access technologies, focusing mainly on the data link layer. On the other hand, the aim is to present the principles of network layer communication, covering both wired and wireless networks, with special emphasis on routing algorithms in fixed and ad hoc environments, multicast, and mobility over IP networks. The topic then introduces the different architectures of network applications, client-server and peer-to-peer communication models, and the principles of cloud-based communication. Finally, it covers some specific applications and then briefly touches on the issue of the Internet of the Future and the Internet of Things.