TCP Connections and Reliable Byte Streams in Computer Networking
TCP turns the network's unreliable packets into an ordered, reliable byte stream between two endpoints, opened by a handshake, held open for the exchange, and closed when either side is done. After learning this a student can say what a connection is, why bytes arrive in order and without gaps, and what it costs to open one. They can then read an application protocol as text carried over that stream rather than as magic that reaches the server on its own.
TCP Reliability, Flow Control, and Connection Management
Video tutorial: TCP Reliability, Flow Control, and Connection Management