16.1 Network Infrastructure Concepts
16.1.6 Token ring and FDDI
Token Ring
Token ring was originally developed by IBM and then became IEEE standard 802.5. The Token Ring network architecture uses the ring topology and a token to provide access for workstations. The token passes around the ring and when a workstation has the token, it can place data on the ring. Token ring is commonly implemented as a star with a central concentration device known as a multi-station access unit or MAU and is technically a star ring. Token ring speeds are either 4 or 16Mbps.

Fiber Distributed Data Interface (FDDI)
Pronounced "fiddi", FDDI is an ANSI standard and was developed primarily as a backbone technology to interconnect LANs in a campus environment. It runs over fiber optic cable and can span many miles. FDDI uses two rings, one primary and one for backup. It transmits data at 100Mbps using the token passing access method.