Other versions v1 to v9 were defined, but only v4 and v6 ever gained widespread use. v1 and v2 were names for TCP protocols in 1974 and 1977, as there was to separate IP specification at the time. v3 was defined in 1978, and v3.1 is the first version where TCP is separated from IP. v6 is a synthesis of several suggested versions, v6 "Simple Internet Protocol", v7 "TP/IX: The Next Internet", v8 "PIP — The P Internet Protocol", and v9 "TUBA — Tcp & Udp with Big Addresses".