A2.1 Network fundamentals

Computer networks serve different purposes and vary in scale, from personal area networks (PANs) to wide area networks (WANs), including specialized types like virtual private networks (VPNs). Modern digital infrastructures—such as cloud computing, mobile networks, and edge computing—enable global communication and computing, but also introduce limitations like latency, bandwidth constraints, and security risks. Key network devices like routers, switches, and wireless access points function at specific layers of the TCP/IP model and enable data transmission within and across networks. Protocols such as TCP, UDP, HTTP, and DHCP govern how data is formatted, transmitted, and received, while the TCP/IP model (HL only) organizes these processes into four structured layers to ensure reliable and interoperable communication.