Introduction
Open System Interconnection (OSI) is a reference model that specifies how information from one computer's software app passes through a physical media to another computer's software app. The OSI comprises seven levels, each of which performs an independent task.
The seven layers of the OSI model are as follows:
- Physical Layer
- Data Link layer
- Network layer
- Transport layer
- Session layer
- Presentation Layer
-
Application Layer
In this article, we will be focusing on the physical layer. The physical layer is the OSI model's lowest layer, and it's the one nearest to the physical media.
Also See, Basic Networking Commands
What is a Physical Layer?
The physical layer’s main functionality is transmitting data from one computer to another. This is the lowest layer of the OSI model and comes under the category of hardware layer.
This layer provides an electrical, mechanical, and procedural interface to the transmission medium. It consists of several network components like connectors, receivers, cables etc. It defines the transmission of raw bits over the data link layer. This layer interfaces with the data link layer and perform symbol encoding, transmission, reception and decoding.
According to network specifications, this layer controls most of the network's physical connections, including wireless transmission, cabling, cabling standards and types, connectors and types, network interface cards, and more. On the other hand, the physical layer does not deal with the actual physical medium (like copper).
Functions of Physical Layer
- It defines the rate of transmission, which is the number of bits used per second.
- It deals with the synchronization of the transmitter and receiver at bit level.
- It provides the transmission interface between devices and transmission media.
- It helps in the direction of transmission between two devices.
- It helps in physical topology decisions.
- It provides a switching mechanism where data packets can be transmitted from one port to the destination port.
-
This layer connects devices with the medium using two types of configuration, i.e. Point to Point configuration and Multipoint configuration. A link is fully dedicated to carrying the data between two devices in the Point-to-Point configuration whereas, in Multi-Point configuration, there is a link through which multiple devices are connected.
Physical Layer Devices:
- Repeaters
- Hubs
- Network Interface cards (NICs)
-
Cables and Connectors
Also see, Message Switching in Computer Networks and Personal Area Network
117+ registered 