What is "token ring"

n. (context computing English) A network standard invented by IBM and later defined by the 802.5 subcommittee of the IEEE which provides for a network with a star ring topology, and which operates by passing a token frame around the logical ring.

thumb|Two examples of token ring networks: a) Using a single MAU b) Using several MAUs connected to each other thumb|Token ring network thumb|IBM hermaphroditic connector with locking clip

Token ring local area network (LAN) technology is a communications protocol for local area networks. It uses a special three-byte frame called a "token" that travels around a logical "ring" of workstations or servers. This token passing is a channel access method providing fair access for all stations, and eliminating the collisions of contention-based access methods.

Introduced by IBM in 1984, it was then standardized with protocol IEEE 802.5 and was fairly successful, particularly in corporate environments, but gradually eclipsed by the later versions of Ethernet.

(The main focus of this article is the IBM/IEEE 802.5 version, but there were several other earlier implementations of token rings).