Internet Protocol/Definition

Highly resilient protocol for messages sent across the internet, first by being broken into smaller packets (each with the endpoint address attached), then moving among many mid-points by unpredictable routes, and finally being reassembled into the original message at the endpoint. IP version 4 (IPv4) is from 1980 but lacked enough addresses for the entire world and was superseded by IP version 6 (IPv6) in 1998.