At what layer does a repeater operate in the OSI model?

A repeater operates at the Physical Layer of the OSI model. This is the lowest layer, responsible for the physical transmission of data over a network medium. Repeaters are designed to amplify or regenerate signals to extend the distance over which data can travel. They work by receiving incoming signals and retransmitting them, thereby overcoming signal loss that occurs over long cable lengths or through obstacles.

Since the repeater deals solely with raw bit transmission and does not interpret or modify the data that is being sent, it functions only at the physical layer, where electrical signals, optical signals, or radio waves are handled. This distinguishes it from the other layers, which involve data formatting, session management, and error handling.