OSI Model:

OSI is Open System Interconnection model.OSi modal solve the complexity in explaning the process of connection between the Clien-server system.It departs the communcation system into subparts called layers.

Osi model consists of 7 layers which are as follows:

1. Physical Layer

1. Data link layer

2. Network Layer

3. Transport Layer

4. SessionLayer

5. Presentation Layer

6. Application Layer

Physical Layer: Physical Layer describes the data transfer medium through which the data transfers like aluminium,copper wires.Physical layer consist of various types of wires like twisted, untwisted pair,optical cable etc.

Data Link Layer:Data link layer provides functions to transportation the data and datermine the errors if any in physical layer and remove them. Data link layer maintains the physical and logical interconnections between the devices.

Network Layer:Network layer constructs the path to transfer the data between various networks.

Functions of network layer are:

1. Data transfer

2. Dividing the data in subparts

3. reconsructing the data in sequence

4. Report the errors.

Transport Layer : Transport layer deals with the transmission of data . Transmission process can be of two types:

Connection oriented

Connection less

Connection Oriented:In this type of communication a path is established between the host and the client. The data sent in the order from the host is received in the same order by the client.No data is loss occurred.

Connection Less :Connection less transmission is of random order it means the data is transfered in the random order. Data loss may be occured over here.

Session Layer:Session layer manages the connections between the systems.It connects,maintains and disconnect the conections between the host and clients.It deals with point to point connections between the servers.

Presentation Layer :Presentation layer determines how the data is represented to the user. It is responsible for formatting and encryption of data. Presentation layer decidec in which format the data will be represented.

Application Layer: Applcation layer provides the end-user services.Application layer is responsible for the distribution of resources,approving the user requests..If detects whther the user is present to tranmit the data and also detect whether the resources are available to be transmitted.

It is connected to the user directly.