OSI Top Layers

Question 1

What are the top three layers of the OSI model?

Answer 1

Application, Presentation, Session

These layers are responsible for network services, data formatting, and managing data exchange.

Question 2

What is the primary function of the Application Layer?

Answer 2

Network services to user application (e.g., HTTP)

The Application Layer interfaces directly with the end-user applications.

Question 3

What does the Presentation Layer do?

Answer 3

Formats data and performs encryption/decryption

It ensures that data is in a usable format for the receiving device.

Question 4

What is the role of the Session Layer?

Answer 4

Manages data exchange and end-to-end connections

It keeps communication sessions organized and ensures synchronization.

Question 5

What does HTTP stand for?

Answer 5

Hypertext Transfer Protocol

HTTP defines how web browsers request and receive web pages from servers.

Question 6

What are the components of an HTTP request?

Answer 6

Start line, message headers, blank line, message body

This structure facilitates the communication between client and server.

Question 7

True or False: HTTP is a stateful protocol.

Answer 7

False

HTTP transactions are stateless, meaning each request is independent.

Question 8

What are the 4 types of HTTP requests?

Answer 8

• GET
• PUT
• DELETE
• POST

Each type of request serves a different function in data handling.

Question 9

What is the function of the Domain Name System (DNS)?

Answer 9

Translates URLs into IP addresses

DNS allows users to access websites using human-readable addresses.

Question 10

What protocols are commonly used for web browsing?

Answer 10

• HTTP
• HTTPS

HTTPS is the secure version of HTTP, using SSL/TLS for encryption.

Question 11

What is the difference between lossless and lossy compression?

Answer 11

• Lossless: No data lost (e.g., PNG)
• Lossy: Some data lost (e.g., JPEG)

The choice of compression affects data quality and size.

Question 12

What is the role of the Session Layer in video conferencing?

Answer 12

Keeps audio and video in sync

This ensures a smooth communication experience without delays.

Question 13

What does authentication in the Session Layer involve?

Answer 13

Verifying user identity with usernames and passwords

This ensures that only authorized users can access the system.

Question 14

What is the purpose of the Session Layer in file sharing?

Answer 14

Handles communication between devices

It enables organized data exchanges and manages sessions effectively.

Question 15

What does the term ‘authorisation’ refer to in the Session Layer?

Answer 15

Controls what resources a user can access based on permissions

This is critical for maintaining security and privacy in systems.

Question 16

What is the main purpose of the transport layer in the OSI model?

Answer 16

Segmentation, transfer and reassemble, uses ports and sockets

This layer ensures reliable data transfer between devices.

Question 17

How does the Network Layer function in terms of addressing?

Answer 17

Uses logical addressing for path determination

This is essential for routing data packets across networks.

Question 18

What kind of addressing does the Data Link Layer use?

Answer 18

Physical addressing

This layer prepares data for transmission over physical media.

Question 19

What is the main function of the Physical Layer?

Answer 19

Media, signal and binary transmission

It deals with the actual physical connection and data transmission.