At which layer of the OSI model do hubs and repeaters operate?

Hubs and repeaters operate at the Physical Layer of the OSI model. This layer is responsible for the transmission and reception of unstructured raw data over a physical medium. Hubs serve as central connection points that facilitate communication between devices on a network by simply repeating incoming signals to all connected devices, without any data processing or filtering. Similarly, repeaters regenerate signals to extend the distance that data can travel over a network medium.

This focus on the physical aspects of network connectivity distinguishes the Physical Layer from other layers, such as the Data Link Layer, which deals more with data framing, error detection, and flow control, or the Transport Layer, which manages end-to-end communication and error recovery. Hubs and repeaters do not interpret or manage data frames or packets; they solely ensure that the electrical or optical signals representing the data maintain their integrity over distances.