Token Ring is standardized in IEEE 802.5 that was published in 1985. The protocol deals with the problem of collision, which is defined as a state were two stations transmit at the same time. In order to avoid the situation of collision there was a need to control the access to the network. The token is passed from one station to another according to a set of rules. The ring consists of ring stations and transmission medium.
Data travels sequentially from station to station.
Only the station in possession of the token is allowed to transmit data. Each station repeats the data, checks for errors, and copies the data if appropriate. The token Ring protocol supports priorities in transmission. It is implemented setting the priority bits in the Token Ring Frame. The First release of Token Ring version was capable of 4Mbs data transmission rate, the transmission rate was improved later to 16Mbs.