Physical Layer – 1st Layer in OSI Model Summary of Contents Toggle What is Physical Layer in the OSI Model?What is the Function of the Physical Layer?What is the Unit of Data Encapsulation in Physical Layer?What are the Protocols used at Physical Layer? What is Physical Layer in the OSI Model? What is the Function of the Physical Layer? What is the Unit of Data Encapsulation in Physical Layer? What are the Protocols used at Physical Layer?