TCP/IP

TCP/IP is a suite of network protocols that enables communication between computers over networks. It is organized in layers (such as link, internet, transport, and application), each responsible for specific functions like addressing, routing, and reliable delivery. TCP (Transmission Control Protocol) provides connection-oriented, reliable data transfer using mechanisms such as the three-way handshake, segmentation, error checking, and flow/congestion control, while IP (Internet Protocol) handles addressing and routing of packets across networks.

Imagine opening a web page: first a DNS query is often performed (application layer) to find the server's address. Your device then initiates a TCP connection to the web server using the three-way handshake; web requests and responses are split into TCP segments and carried as IP packets across multiple routers to the destination. If packets are lost, TCP detects this and requests retransmission; finally the segments are reassembled so the browser can render the full page.