What are the key features of a ring topology?

A ring topology consists of a set of stations connected serially by cable. In other words, it�s a circle or ring of computers. There are no terminated ends to the cable; the signal travels around the circle in a clockwise direction.

Note that while this topology functions logically as ring, it is physically wired as a star (see FAQ 9). The central connector is not called a hub but a Multistation Access Unit or MAU. (Don�t confuse a Token Ring MAU with a �Media Adapter Unit� which is actually a transceiver.)

Under the ring concept, a signal is transferred sequentially via a "token" from one station to the next. When a station wants to transmit, it "grabs" the token, attaches data and an address to it, and then sends it around the ring. The token travels along the ring until it reaches the destination address. The receiving computer acknowledges receipt with a return message to the sender. The sender then releases the token for use by another computer.

Each station on the ring has equal access but only one station can talk at a time.

In contrast to the �passive� topology of the bus, the ring employs an �active� topology. Each station repeats or �boosts� the signal before passing it on to the next station.

Rings are normally implemented using twisted pair or fiber-optic cable.