With Token Passing, a small message, called a token, constantly circulates around the ring. If the token is marked as free, the host that receives the ”free” token can transmit its data and mark the token as busy. All the hosts along the ring receive the data and the busy token, until the host that sent the original message sets the token free again.
Right now the token is with host B, and it is marked free. Let’s say that host B wants to send data to host D. B sets the token to busy and adds its data. The host C has now received the token and the data, but since C is not the receiver it just passes on the token and the data into the ring.
The host D receives the data and sets the token to copied. The token and the data are then
passed on into the ring.
The host A just passes on the token and the data. The host B sees that the data has been received in a proper way by D. B therefore deletes the data and sets the token …