During transmissions over localhost which layers are used in OSI Model?

Question

While transmiting data via localhost address or 127.0.0.1 which layers are used in the OSI model?

I believe communication starts through application layer and goes down till some layer but no data goes through physical layer, or does any?

Answer 1

Traffic to 127.0.0.1 will be looped back by the internet layer of the TCP/IP model, which is matched in the OSI model by the Network layer. This is the layer where routing and address resolution take place.