What is physical layer?
In the Open Systems Interconnection (OSI)communications model, the physical layer supports the electrical or mechanical interface to the physical medium. For example, this layer determines how to put a stream of bits from the upper (data link) layer on to the pins for a parallel printer interface, an optical fiber transmitter, or a radio carrier. The physical layer is usually a combination of software and hardware programming and may include electromechanical devices. It does not include the physical media as such.
Which layer of the OSI model is primarily concerned with accessing the physical media and physical addressin?
It depends on which textbook you are reading; some textbooks state that the frame is constructed in the data link layer (layer 2) and transmitted out the physical layer as a packet. Some other textbooks will say that the packet is created in layer 2 and transmitted out the physical layer as a frame.
There are various devices that are used at different layers in OSI model. Most common of them are: 1.) Hub: It is used at Physical Layer. 2.) Switches: It is used at Data link layer. 3.) Bridges : It is used at Data link layer. 4.) Routers: It is used at Network layer. 5.) Gateway: It is used at all layers. 6.) NIC (Network Interface Card): It is used at physical and datalink layer. 7.)…