Layers of OSI Model

Layers of OSI Model

The top layer of the OSI model is the Application Layer.

Application Layer -

This layer deals with application.

The purpose of this layer is to manage communications between applications.

It supports application protocols such as email, HTTP and FTP.

At this layer, data still resembles something that people can read.

Presentation Layer -

This layer is where data is first converted into a form that can be sent over a network.

Data is compressed and decompressed and encrypted or decrypted.

This layer is sometimes refer to as translation layer.

Session Layer -

This layer controls the dialog during communications.

It establishes, managed and terminates the connections between the local and remote application.

This layer is also known as the "the traffic cop" because it directs network traffic.

Transport Layer -

This layer provides the transfer of data between end users.

Responsible for re sending any packets that do not receive an acknowledgement from the destination.

This layer can guarantee that packets are received.

Network Layer -

This layer is responsible for routing the data packet based on its logical IP address.

It fragments and reassembles the packets.

Instructs data on how to find its ultimate destination.

Data Link Layer -

This layer is responsible for sending data to the physical layer.

Data packets are encoded and decoded into bits.

Handles flow control and frame synchronization.

Divided into 2 sub-layers, the Media Access (MAC) Control layer and the Logical Link Control (LLC) layer.

Physical Layer -

This layer defines the network standards and physical characteristics of a network such as connectors, media types, cables , voltages etc.

Defines the topology of a network