Physical Layer of the OSI Model

Knoji reviews products and up-and-coming brands we think you'll love. In certain cases, we may receive a commission from brands mentioned in our guides. Learn more.
Physical Layer of the OSI Model Physical Layer is the first or the bottom most layer of the OSI model. This layer is used to establish or terminate a connection to a communication medium. It also defines the electrical and mechanical specifications like

Physical Layer of the OSI Model

Physical Layer is the first or the bottom most layer of the OSI model. This layer is used to establish or terminate a connection to a communication medium. It also defines the electrical and mechanical specifications like cables, connectors and signaling options of the medium.

Physical Layer receives data from the upper layer called the data link layer. It converts the received data into bit stream. The data is then transmitted through the medium to the receiver. At the receiving end, physical layer receives the data in bit format. It forwards the data to the data link layer.

Responsibilities of the physical layer are:

Characteristics of media - Defines the characteristics of the interface which is used for connecting the devices. It also defines the type of the transmission media such as copper wires or fiber optic cables.

Encoding - Defines the encoding type. Encoding means changing bit stream (Os and 1s) into signal. Before broadcasting, physical layer encodes the signal into electrical or optical form depending upon the media.

Transmission Rate - describes the transmission rate of bits. This supplies number of bits transmitted per second. It describes how long will the length of a bit be.

Transmission Mode - Defines the transmission mode between two devices. Transmission mode specifies the direction of signal flow. The different types of transmission modes are:

Simplex - Communication is done only in one way. One device can only send and the other can only receive.

Half duplex - Communication is done in both the directions but not at the same time

Full duplex - Communication is done simultaneously in both the directions.

Line Configuration - Defines the way in which devices are connected to the appropriate link. For example point to point or multipoint.

The point to point line configuration provides a dedicated link between two devices. But in the multipoint line configuration more than two devices share a single link.

Topology - Defines how the devices are connected to form a network.

Synchronization of Bits - The sender and receiver must use the same bit rate. The clocks of the sender) and receiver must also be synchronized for bit level synchronization.

You may also be interested in understanding the other seven layers of the OSI Model

Application Layer of the OSI Model

Presentation Layer of the OSI Model

Session layer of the OSI Model

Transport Layer of the OSI Model

Network Layer of the OSI Model

Data Link Layer of the OSI Model

0 comments