In a Token Ring network, a Multistation Access Unit (MSAU) is used in place of the hub that is used on an Ethernet network. The MSAU performs the token circulation inside the device, giving the network a physical star appearance. Each MSAU has a Ring In (RI) port on the device, which is connected to the Ring Out (RO) port on another MSAU. The last MSAU in the ring is then connected to the first, to complete the ring. Because Token Ring networks are few and far between nowadays, it is far more likely that you will find yourself working with Ethernet hubs and switches.
Even though MSAU and Token Ring networks are not common, you can expect a few questions on them on the exam.