This document explains communication in computer science, focusing on networks (LAN, WAN), client-server and peer-to-peer models, and network topologies. It covers wired and wireless transmission methods, Ethernet, bit streaming, and cloud computing. It also introduces internet infrastructure, IP addressing (IPv4 vs. IPv6), subnetting, public vs. private IPs, DNS, and the role of network devices like routers, switches, and modems.