In an FDDI LAN, the nodes that can be the source or destination of data frames are called stations. A station has a MAC layer, one or more MAC addresses, and one or more FDDI ports. The stations share the bandwidth provided by the ring.
As was the case for Token Ring, cabling management often is simplified by connecting stations to a concentrator (hub) unit. A concentrator can play its role invisibly. However, it will need a MAC layer and a MAC address if it is going to be configured or supervised via network management messages. In this case, it will have the status of a station, too.
Normally, most stations are connected to concentrators that are attached to a central ring called the trunk. Concentrators can be cascaded, ...