Start Delimiter Indicates the beginning of a frame by employing a signaling pattern that differentiates it from the rest of the frame. Frame Control Indicates the size of the address fields and whether the frame contains asynchronous or synchronous data, among other control information. As with Ethernet and Token Ring addresses, FDDI destination addresses are 6 bytes long. Source Address Identifies the single station that sent the frame. As with Ethernet and Token Ring addresses, FDDI source addresses are 6 bytes long.
Data Contains either information destined for an upper-layer protocol or control information.
The destination address recalculates the value to determine whether the frame was damaged in transit. If so, the frame is discarded. End Delimiter Contains unique symbols, which cannot be data symbols, which indicate the end of the frame. Frame Status Allows the source station to determine whether an error occurred and whether the frame was recognized and copied by a receiving station.