Ethernettoistin

An Ethernettoistin, commonly known in English as an Ethernet repeater, is a network device that regenerates and forwards electrical or optical signals between Ethernet segments. Operating at the physical layer (layer 1) of the OSI model, it does not interpret frames or participate in MAC addressing. Instead, it simply re-transmits incoming signals to other ports, allowing signals to travel farther than the fundamental segment length.

In copper Ethernet, a repeater regenerates the signal timing and voltage levels to extend the distance between network segments. In modern networks, true repeaters are rare; many devices marketed as hubs or media converters include repeater functionality. Some repeaters also support media conversion between copper and fiber, enabling connectivity between different transmission media while preserving the same data rate and protocol.

Repeaters introduce additional propagation delay and do not segment collision domains. Because they do not inspect or filter traffic, they do not provide MAC-level filtering or switching. Consequently, the network performance and efficiency depend on the overall design, and repeaters are typically used only to extend reach in limited scenarios. The practical distance extension is constrained by the Ethernet standard in use and the electrical or optical characteristics of the device.

Historically, Ethernet repeaters were common in early Ethernet networks that used coaxial cables or simple hub-based topologies. With the rise of switches and advanced media converters, the use of standalone Ethernet repeaters has diminished, though similar devices may still be employed to connect legacy media or to extend networks where switching is not desirable or feasible.