All layers.
Hubs and repeaters operate at the Physical Layer of the OSI Model. The Physical Layer is the first layer of the OSI Model.
Hubs are a physical layer (layer 1) device; most switches operate at the Data Link layer (Layer 2) of the OSI model.
It depends on what kind of model it is, but in the model for computer 321O, it is on the layer between trhe keyboard and the behind screen, and there is a button with the osi code and there says everything.
Layer 3
Repeaters operate at the physical layer of the OSI model.
1. Repeaters (Operate at the OSI Physical Layer).2. Bridges (Operate at the OSI Data Link Layer).3. Routers {and Brouters} (Operate at the OSI Network Layer).
The NIC operates on Layer 2 (Data Link Layer) of the OSI Model.
Router works in Network Layer of OSI model
Network Layer
Layer 2 - Data Link
Layer 5 - Session layer
it works in layer 2