Token Ring

The main (but still rare) alternative to Ethernet.

Developed by IBM, Token Ring avoids Ethernet's problems of message collisions by using a different strategy.

In some tribal meetings, arguments are prevented by having a "speaking stick" - only the person who is holding the stick is allowed to speak. When finished, the speaker hands the stick to someone else so they are allowed to talk.

Token Ring works the same way: all computers and devices on the network must hold their tongues until a special network message called the Token is in their possession.

1. The ring initializes by creating a token, which is a special type of frame that gives a station permission to transmit.
2. The token circles the ring like any frame until it encounters a station that wishes to transmit data.
3. This station (whom I like to refer to as "The Lord of the Ring") then "captures" the token by replacing the token frame with a data-carrying frame, which passes around the network and the message is grabbed by the station it was addressed to.
4. Once that data frame returns to the transmitting station, that station removes the data frame, creates a new token and forwards that token on to the next node in the ring. So, every node is guaranteed to eventually gets a chance to speak regardless of how busy the network is.