IEEE(802.5) TOKEN RING:
Token ring was developed based on the concept of ring topology by IBM. It is also defined as ieee 802.5.In token ring network a simple mechanism empolyed known as token passing. In token ring consist very special bit pattern known as token, in this tokenring it consist of number interconnected in the form of ring stations.
It connected in point-to-point link in this each station acts as a repeater which regenerates the original signal and send it to the next computer.
When a computer or host wants to transmit information it cannot transmit immmediately in which host will wait for the permission in which all other nodes are not tansmit at the same time then the host will transmit the information.
When a host or computer tranmit a frame to destination, which travels across the ring.the frame passes to each host on the ring has to accept it and compares the destination address in the frame, if the destination address is finds makes a copy of it otherwise that frame pass to next host.
Where at the destination node,checks the CRC if any error present in the frame,if no error is in the frame, that frame accept it. And the frame circulates on the ring until it reaches the source, this removes the frame from the ring.
Let’s consider a station A wants to send a frame to station D as shown in figure. The frame has destination address(D) and source address(A) the frame passes through the station B and C which acts as repeater and forward the frame to the next link,they do not copy the frame as the frame is not addresssed to then. Station D finds its address of the frame and copies it address. The frame continues its journey and reaches its station A. the frame does not circulates again around the ring and a station A removes the frame from the ring.
