Читать книгу Understanding Infrastructure Edge Computing - Alex Marcham - Страница 44

From a physical perspective, the first layer of the OSI model is at the bottom, layer 1. This layer is known as the physical layer and is responsible for encapsulating the functions of the network which are concerned with the physical transmission medium that is being used to send and receive data, whether that be radio frequency (RF), in the case of many wireless networks, copper cabling, fibre optic cabling, or another medium of choice. Although these three options are the most commonly used today, other options such as infrared (IR) light exist and are used in some specific use cases.

As well as the physical transmission medium itself, layer 1 includes the functions that are needed to encode and decode all data transmissions using that medium. For example, to send and receive data across copper cabling, an encoding scheme must be used to convert some digital application data into a sequence of physical electrical energy, which is then applied to the copper transmission medium, which carries those electrical signals to the remote end of the transmission medium where a corresponding decoding scheme reverses the process, turning these electrical signals back into the digital application data which they represented and passing this data up to layer 2 of the stack.