Overview of the Internet

This chapter explains the basic functioning of the Internet. Examples of the boid simulation are used to discover what happens when messages are sent between two hosts. The chapter introduces the layers of the Internet in turn, from application level down to link and physical layers. Two cross-cutting issues that are particularly relevant to networked virtual environments and NGs (network games)—multicast and quality of service (QoS)—are also discussed. The term Internet was derived from the process of internetworking of networks, where each network was a local island of connectivity, a LAN, that uses a specific networking technology. There are many networks, and many Internets, but the Internet is the world-wide public network. A network, and thus the Internet, connects host computers or just hosts. Each network connects hosts together using some form of communication technology. A communication technology comprises a specific physical technology (wires, electromagnetic radiation, etc.) and protocols for using that technology (Ethernet, 802.11 WiFi, etc.). While small networks might use a single communication technology, for larger networks routers and switches connect different networks together. Some terms that are often used are clients, servers, and peers. These refer to application processes running on hosts. This chapter also introduces a small suite of tools, which can help explore how the network works.