OSI Model

Question 1

What does OSI stand for?

Answer 1

Open Systems Interconnection

Question 2

What is the primary purpose of the OSI model?

Answer 2

To describe the process that data takes as it traverses networks

Question 3

Does the OSI model describe specific protocols?

Answer 3

No, it provides a broad overview applicable to many protocols

Question 4

What is the top layer of the OSI model?

Answer 4

OSI layer 7, the application layer

Question 5

What is the bottom layer of the OSI model?

Answer 5

OSI layer 1, the physical layer

Question 6

List the OSI layers from layer 7 to layer 1.

Answer 6

• Application layer (Layer 7)
• Presentation layer (Layer 6)
• Session layer (Layer 5)
• Transport layer (Layer 4)
• Network layer (Layer 3)
• Data link layer (Layer 2)
• Physical layer (Layer 1)

Question 7

What mnemonic can help remember the OSI layers?

Answer 7

All People Seem To Need Data Processing

Question 8

What does the physical layer deal with?

Answer 8

Physical signals sent through cables and fibers

Question 9

What types of problems are associated with OSI layer 1?

Answer 9

• Bad cables
• Bad fiber
• Wireless interference

Question 10

What is the main function of OSI layer 2?

Answer 10

Communication between two devices on the network

Question 11

What does MAC stand for in the context of networking?

Answer 11

Media Access Control

Question 12

What is the primary purpose of OSI layer 3?

Answer 12

Routing traffic based on destination IP addresses

Question 13

What protocols operate at OSI layer 4?

Answer 13

• TCP (Transmission Control Protocol)
• UDP (User Datagram Protocol)

Question 14

What is the role of the session layer (Layer 5)?

Answer 14

Manages communication sessions between devices

Question 15

What is the function of the presentation layer (Layer 6)?

Answer 15

Formats data for human readability, including encryption and decryption

Question 16

What types of applications operate at OSI layer 7?

Answer 16

• HTTP
• HTTPS
• FTP
• DNS
• POP3

Question 17

Fill in the blank: The data link layer is also known as the _______.

Answer 17

MAC address layer

Question 18

What are the two types of addresses mentioned in OSI layer 2?

Answer 18

• EUI-48 addresses
• EUI-64 addresses

Question 19

What is the function of routers at OSI layer 3?

Answer 19

To determine the next hop for traffic based on IP addresses

Question 20

What is a common task at OSI layer 4?

Answer 20

Fragmenting data into smaller pieces for transmission

Question 21

What is a characteristic of OSI layer 5 protocols?

Answer 21

They manage the initiation and termination of sessions

Question 22

What does SSL/TLS operate at in the OSI model?

Answer 22

Layer 6, the presentation layer

Question 23

What type of data does OSI layer 1 deal with?

Answer 23

Signals and raw data transmission

Question 24

What does Wireshark allow you to do related to the OSI model?

Answer 24

Capture and analyze network data across different OSI layers

Question 25

What type of information is displayed in the top window of Wireshark?

Answer 25

Frame-by-frame breakdown of captured data

Question 26

What does the middle window in Wireshark show?

Answer 26

Detailed information about the protocols in a frame

Question 27

What does the bottom window in Wireshark represent?

Answer 27

Hexadecimal and ASCII breakdown of the data

Question 28

What is the significance of the highlighted frame in Wireshark?

Answer 28

It allows for analysis of specific captured data

Question 29

What is Ethernet II associated with?

Answer 29

Source MAC address and destination MAC address ## Footnote Ethernet II operates at layer 2 of the OSI model, which is the data link layer.

Question 30

What layer of the OSI model does the Internet Protocol (IP) fit into?

Answer 30

Layer 3, the network layer ## Footnote IP addresses are listed for both source and destination in this layer.

Question 31

What does a DNS resolution show in this context?

Answer 31

The association of an IP address with a domain name ## Footnote Example: The IP address 72.14.247.19 is associated with googlemail.l.google.com.

Question 32

Which protocol is used for the Google Mail communication described?

Answer 32

Transmission Control Protocol (TCP) ## Footnote TCP operates at layer 4, the transport layer, of the OSI model.

Question 33

What is the destination port number indicating in this example?

Answer 33

Port 443 ## Footnote This indicates communication over an encrypted channel using HTTPS.

Question 34

What layers of the OSI model does the secure socket layer encapsulate?

Answer 34

Layers 5, 6, and 7 ## Footnote These layers are the session layer, presentation layer, and application layer respectively.

Question 35

What type of information is found at the physical layer?

Answer 35

Electrical signals ## Footnote The physical layer is layer 1 of the OSI model.

Question 36

What type of information is present at the data link layer?

Answer 36

Ethernet frame information ## Footnote This is layer 2 of the OSI model.

Question 37

What encapsulates the TCP port numbers?

Answer 37

TCP encapsulation ## Footnote This is found at the transport layer, which is layer 4 of the OSI model.

Question 38

What does the presentation layer perform in this context?

Answer 38

SSL or TLS encryption and decryption ## Footnote The presentation layer is layer 6 of the OSI model.

Question 39

What is referred to at layer 7 of the OSI model?

Answer 39

Google Mail front end ## Footnote This layer is the application layer, where sending and receiving emails occurs.

Question 40

True or False: The OSI model can be applied to any communication occurring over the network.

Answer 40

True ## Footnote This broad description helps IT professionals communicate about specific layer-related issues.

Question 41

Fill in the blank: The secure socket layer is associated with layers ______, ______, and ______ of the OSI model.

Answer 41

5, 6, 7 ## Footnote These correspond to the session, presentation, and application layers respectively.