The most popular example of the round robin protocol is the token-passing protocol. Before a workstation can transmit, it must possess the token. Once the transmission is complete, the workstation releases the token to the next workstation, in round robin order. Eventually, the token is passed around to all workstations and returns to the first workstation, to begin another cycle. Two types of token-passing protocols exist: token ring and token bus. While they both use a token-passing algorithm, they have different underlying topologies. Let’s introduce the more popular of the two algorithms—token ring. Since the token bus has essentially passed into nonexistence and is similar to the token ring, we will not discuss it further.