Every email you send is broken into tiny pieces called packets that travel independently across the internet to reach their destination.

The concept of packet switching was independently developed in the early 1960s by Paul Baran at the RAND Corporation and Donald Davies at the National Physical Laboratory in the UK. This technology became the foundation for ARPANET, the precursor to the modern internet, which sent its first message in 1969. Unlike traditional circuit switching used by telephone networks, packet switching does not require a dedicated connection between two points.Each packet consists of a payload—the actual data being transmitted—and a header containing the IP addresses of both sender and receiver. The Transmission Control Protocol (TCP) manages the splitting and reassembling process, while the Internet Protocol (IP) handles the routing decisions. Because each packet is individually addressed, they can take entirely different physical paths across the globe depending on current traffic levels and server availability.If one path becomes blocked or a server fails, packets simply reroute through another node automatically. This decentralized design makes the internet incredibly resilient and fault-tolerant. When packets reach their destination, TCP verifies that all pieces have arrived and requests retransmission of any missing data. This entire process occurs in milliseconds, enabling the seamless communication we experience today through protocols like SMTP for email.