Token Ring
Token Ring is a LAN network technology provided by IBM. It was introduced by IBM in 1984 and standardized as IEEE 802.5 in 1989.
As the name implies, it uses a token-passing methodology for arbitration on a physical ring topology.
Original 1985 Token Ring provided 4 Mbit/s speed, while the later 1988 IEEE standard provided 16 Mbit/s.
Please see The Token Ring page in our wiki for the [limited] information we've gathered so far. Contributions are more than welcome!