Physical layer

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OSI Model
7Application layer
6Presentation layer
5Session layer
4Transport layer
3Network layer
2Data link layer
1Physical 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, for example.

The major functions and services performed by the physical layer are:

Contents

Physical signaling sublayer

In a local area network (LAN) or a metropolitan area network (MAN) using open systems interconnection (OSI) architecture, the Physical signaling sublayer is the portion of the physical layer that:

Source: from Federal Standard 1037C

Examples

Hardware Examples

Note: Physical layer Associated with transmission of unstructured bit streams over a physical link. Responsible for the mechanical, electrical and procedural characterstics that establish, maintain and deactivate the physical link.

See also

da:Det fysiske lag de:Physische Schicht fr:Couche physique it:Livello fisico sv:Fysiskt skikt zh:物理层