Layer 1: The physical layer
The physical layer is level one in the seven level OSI model of computer networking. It performs services requested by the data link layer. This level refers to network hardware , physical cabling or a wireless electromagnetic connection . It also deals with electrical specifications, collision control and other low-level functions.
The physical layer is the most basic network layer, providing only the means of transmitting raw bits. The shapes of the electrical connectors , which frequencies to broadcast on, and similar low-level things are specified here. An analogy of this layer in a physical mail network would be a specification for various kinds of paper and ink.
The major functions and services performed by the physical layer are:
- Participation in the process whereby the communication resources are effectively shared among multiple users, e.g., contention resolution and flow control.
- Conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel .
Examples:
click next Chapter -
Protocols
|
