7 Layers of OSI (Unit 3)

Question 1

Enables user applications (like web browsers, email clients, and file transfer programs) to access network services.
This layer deals with high-level protocols like HTTP, FTP, and SMTP.

Answer 1

Application Layer

Question 2

Ensures data is presented in a format the application layer can understand.
This might involve encryption, decryption, compression, and character set conversion.

Answer 2

Presentation Layer

Question 3

Maintains connects and is responsible for controlling ports and sessions between communicating applications.
This layer is responsible for authentication, authorization, and security negotiations.

Answer 3

Session Layer

Question 4

Provides reliable data transfer between applications on different hosts.
Transmits data using transmission protocols including TCP (Transmission Control Protocol) and UDP (User Datagram Protocol)

Answer 4

Transport Layer

Question 5

Determines the logical path data will take between source and destination networks.
This layer uses IP (Internet Protocol) for routing and addressing.

Answer 5

Network Layer

Question 6

Handles physical addressing and error detection for data transmission over a single network segment.
This layer uses MAC (Media Access Control) addresses and protocols like Ethernet.

Answer 6

Data Link Layer

Question 7

Transmits raw data bits over the physical network medium (e.g., cables, fiber optics, or wireless signals).
This layer deals with the electrical, optical, or radio characteristics of the transmission medium.

Answer 7

Physical Layer

Question 8

OSI means

Answer 8

Open System Interconnection

Question 9

The OSI reference model was created by the

Answer 9

International Organization of Standardization

Question 10

It describes how data and network information are communicated from an application on one computer through the network media to an application on another computer.

Answer 10

OSI model

Question 11

Set of guidelines for application developers creating network-based applications. Conceptual blueprint for communication, dividing processes into layers. Resulting design is known as layered architecture.

Answer 11

Reference models

Question 12

Upper layer of the OSI reference model

Answer 12

Application, Presentation, Session

Question 13

It is the spot where users actually communicate to the computer.

This layer is acting as an interface between the actual application program

Answer 13

Application Layer

Question 14

Presents data to the application layer, handles data translation and code formatting.

Acts as a translator, managing coding and conversion tasks like compression, decompression, encryption, and decryption according to OSI protocol standards.

Answer 14

Presentation Layer

Question 15

layer is responsible for setting up, managing, and tearing down sessions between presentation layer entities.
This layer also provides dialogue control between devices, or nodes.

Answer 15

Session Layer

Question 16

The session layer coordinates communication between systems and serves to organize their communication by offering three different modes:

Answer 16

simplex, half-duplex, and full – duplex.

Question 17

Segments and reassembles data streams. Provides end-to-end transport services and establishes logical connections between hosts. Handles multiplexing, session establishment, and virtual circuit teardown. Hides network-dependent details for transparent data transfer.

Answer 17

Transport Layer

Question 18

Prevents sending host from overflowing buffers of receiving host , avoiding data loss. Connection-oriented communication ensures reliable data transport. Allows receiver to regulate sender’s data transmission.

Answer 18

Flow control

Question 19

Types of Control Flow

Answer 19

Buffering
Congestion avoidance
Windowing

Question 20

In reliable transport operation, a device that wants to transmit sets up a connection – oriented communication with remote device by creating a

Answer 20

session

Question 21

The quantity of data segments that the transmitting machine is allowed to send without receiving an acknowledgement for them is called a

Answer 21

Window

Question 22

The datagram will store in memory section called

Answer 22

Buffer

Question 23

Ethernet term that describes a situation where one device’s transmission forces all others on the segment to pay attention. If multiple devices transmit simultaneously, a collision occurs, leading to retransmissions and inefficiency.

Answer 23

Collision domain

Question 24

Was developed by ISO to promote interoperability among network devices and software. Primary architectural model for networks, describes data and network communication between applications on different computers.

Answer 24

OSI Model

Question 25

Advantages of Reference Model

Answer 25

SIMPLIFIED - Simplifies communication by breaking processes into smaller parts.

STANDARDIZATION - Enables multiple vendor development through standardization.

FUNCTIONALITY - Promotes industry standardization by defining functions per layer.

COMMUNICATION - Facilitates communication between diverse network hardware and software.

SMOOTH OPERATION - Prevents changes in one layer from impacting others, ensuring smooth development.

Question 26

Lower Layer of the OSI Reference Model

Answer 26

Transport, Network, Data Link, Physical

Question 27

Establishes session with remote device for reliable transmission. Begins with call setup or three-way handshake. Data is then transferred, followed by call termination to tear down circuit.

Answer 27

Connection – oriented communication