The most widely used MAC approach for a ring topology is token ring, defined in
ID: 3622000 • Letter: T
Question
The most widely used MAC approach for a ring topology is token ring, defined in IEEE 802.5. The token ring technique is based on the use of a small frame, called a token, that circulates when all stations are idle. A station wishing to transmit must wait until it detects a token passing by. It then seizes the token by changing one bit in the token, which transforms it from a token to a start-of-frame sequence for a data frame. The station then appends and transmits the remainder of the fields needed to construct a data frame. When a station seizes a token and begins to transmit a data frame, there is ano token on the ring, so other stations wishing to transmit must wait. The frame on the ring will make a round trip and be absorbed by the transmitting station. The transmitting station will insert a new token on the ring when both of the following conditions have been met: (1) The station has completed transmission of its frame. (2) The leading edge of the transmitted frame has returned (after a complete circulation of the ring) to the station.
Explanation / Answer
Dear, a) Under better efficiency when the ring is longer than the frame in terms of time early token result in improved utilization b)Multiple tokens can complicate access control. Hope this will help you