A computer network consists of two or more nodes (devices such as computers, phones, or servers) connected by links (cables or wireless signals) to share data. Networks are categorized by physical scale, primarily as Local Area Networks (LANs), which connect devices in a single location like a home or office, and Wide Area Networks (WANs), which span large geographical distances.

The Internet is the largest WAN and functions as a network of networks—millions of independent networks interconnected by agreeing to use shared protocols. Protocols provide the agreed-upon rules for formatting and exchanging data, allowing diverse devices across the world to communicate seamlessly.