I'm sorry that I didn't post for about 4 days but I was changing my blog's theme so I coded a lot in these days. In today's post I will talk about the last OSI layer, called the Physical Layer. I want to describe his role, functionality as well as the protocols and standards used at this layer. The Physical Layer is the actual medium in which messages are transmitted. Frames from the Data Link Layer arrive at the Physical Layer for further processing. Here the frames are encoded into streams of bits and then are sent across the network through different media types (copper wires, fiber optic, wireless connections):
There is a good article on Wikipedia in which you can see some different types of physical media and their characteristics: http://en.wikipedia.org/wiki/Ethernet_physical_layer.
You can see some common wireless standards here: http://en.wikipedia.org/wiki/IEEE_802.11.