1.Define the OSI model.

 The OSI model stands for Open Systems Interconnection Model. It is a standard that helps different systems communicate using set of rules. It was created by the International Organization for Standardization (ISO).

2.How many layers are there in the OSI model?

 There are seven layers in the OSI model. These are as follows.

• Physical Layer 
• Data Link Layer 
• Network Layer 
• Transport Layer 
• Session Layer 
• Presentation Layer 
• Application Layer

3.What are packets?

 Packets Provides the necessary routing information to traverse across networks.

Includes information like source and destination IP addresses, sequence number, and error-checking data.

4.What are segments?

It splits large data into smaller parts so they can be sent easily and correctly. It also makes sure the pieces arrive in the right order and without errors.

5.What is the difference between the first and second layers of the OSI model?

 The first layer of the OSI model is the physical layer. Whereas the second layer of the OSI model is the data link layer. 

• Physical Layer:The physical layer connects devices to the network using cables, signals, and hardware like hubs and adapters. It controls how data is physically sent.

• Data Link Layer:The data link layer helps send data between networks. It follows specific rules for transmission and can find and fix errors that might happen in the physical layer.

 6.Which is the fourth layer of the OSI model? And why it is used?

The fourth layer of the OSI model is the transport layer. The main use of this layer is to transfer data. The data is transferred between end users. This layer is built when the IP session for communication beings or ends. The transport layer controls the flow of information and ensures that the information is transferred efficiently and smoothly.

7.What is the use of the application layer?

 The application layer is the top layer of the OSI model. It helps applications communicate easily, even on different systems or networks. It allows file sharing and ensures data is sent correctly by working with the other six layers.

8.What is the role of the fifth layer in the OSI model?

The session layer is the fifth layer of the OSI model. It manages and controls connections between computers, making sure they start, stay active, and end properly. It also helps recover data if there’s a network issue.