In the 1980s, various techniques were developed to increase the data rates of the classic local networks - Ethernet, Token Ring and FDDI. Full Duplex Ethernet (FDE) is one of these techniques, which, however, did not gain any importance because shortly afterwards a technique with a data rate of 100 Mbit/s was standardized with Fast Ethernet.
Full Duplex Ethernet (FDE) is a transmission method closely based on the IEEE 802.3 standard, which extended the bandwidth of Ethernet to 20 Mbit/s by allowing simultaneous transmission and reception on separate lines. Intelligent switching systems were used instead of conventional Ethernet hubs.
Since there were no collisions in full-duplex, neither carrier sensing with carrier sense multiple access (CSMA) nor collision detection (CD) were used in the access method. Therefore, only the frame structure still points to the original Ethernet. An essential feature of the full-duplex technologies was flow control, which protected the receivers from overload.fiber optic cable. In both cases, different transmission paths were available for sending and receiving. This was the only way to implement full-duplex Ethernet.