Chapter 6.1 CENG Network Models

Question 1

What is model?

Answer 1

Model is a representation of the real-world object or process

Question 2

What is OSI?

Answer 2

Open Systems Interconnection

Question 3

What is the Open Systems Interconnect (OSI) Seven-Layer Model? (7 types)

Answer 3

1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer

Question 4

What is the Physical Layer? (OSI)

Answer 4

Physical Layer (Layer 1), is responsible for converting the logical 1s and 0s coming from Layer 2 into some type of physical signal such as a burst of electrons (voltages) or photons (light pulses)

Question 5

What is the Data Link Layer? (OSI)

Answer 5

Data Link Layer (Layer 2), is responsible for controlling when a device should transmit (also known as media access), delimiting the message boundaries of the continuous string of 1s and 0s coming from Layer 1 into packets, and ensuring that the transmission is error free by detecting and sometimes correcting errors

Question 6

What is the Network Layer? (OSI)

Answer 6

Network Layer (Layer 3), is responsible for routing messages along the best route possible by building routing tables and assigning network addresses to devices attached to the network

Question 7

What is the Transport Layer? (OSI)

Answer 7

Transport Layer (Layer 4), is responsible for error checking; flow control; sequencing packets; establishing, maintaining, and terminating conversations; and packetizing larger messages into smaller messages

Question 8

What is the Session Layer? (OSI) IMT

Answer 8

Session Layer (Layer 5), is responsible for initiating, managing, and terminating a communication session; initiating any adjunct services such as logging onto devices, file transfer, or security; and recovering from transport layer interruptions

Question 9

What is the Presentation Layer? (OSI)

Answer 9

Presentation Layer (Layer 6), is responsible for displaying, formatting, and editing inputs and outputs (from the application later). This layer makes it possible to display the same data on different terminal types. This layer may also be responsible for encryption

Question 10

What is the Application Layer? (OSI)

Answer 10

Application Layer (Layer 7), is the interface between the human using the network and the network. A suite of applications exists at this layer such as HTTP (Hypertext Transfer Protocol, also called the Web), e-mail, the Domain Name System (DNS), and File Transfer Protocol (FTP)

Question 11

What is the Transmission Control Protocol/Internet Protocol (TCP/IP) Model? (4 types)

Answer 11

1. Network Interface or Link Layer
2. Internet Layer
3. Transport Layer
4. Application Layer

Question 12

What is the Network Interface or Link Layer? (TCP/IP)

Answer 12

Network Interface or Link Layer (also known as Layer 1), defines the protocols and hardware required to deliver data across a physical network

Question 13

What is the Internet Layer? (TCP/IP)

Answer 13

Internet Layer (also known as Layer 2), defines the protocols for the logical transmission of packets over the network

Question 14

What is the Transport Layer? (TCP/IP)

Answer 14

Transport Layer (also known as Layer 3), defines protocols for setting up the level of transmission service for applications. This layer is responsible for reliable transmission of data and the error-free delivery of packets

Question 15

What is the Application Layer? (TCP/IP)

Answer 15

Application Layer (also known as Layer 4), defines protocols for node-to-node application communication and provide services to the application software running on a computer

Question 16

What does a Typical Ethernet Frame consist of? (9 headings)

Answer 16

1) D. MAC (Yellow)
2) S. MAC (Yellow)
3) D. IP Address (Blue)
4) S. IP Address (Blue)
5) Common Port (White)
6) Return Port number (White)
7) Sequence number (Green)
8) Data (White)
9) FCS (Yellow)

Question 17

What does D. MAC mean?

Answer 17

Destination Media Access Control

Question 18

What does S. MAC mean?

Answer 18

Source Media Access Control

Question 19

What does D. IP Address mean?

Answer 19

Destination Internet Protocol Address

Question 20

What does S. IP Address mean?

Answer 20

Source Internet Protocol Address

Question 21

What does FCS mean?

Answer 21

Frame Check Sequence

Question 22

The internet layer of the TCP model corresponds to which layer of the OSI model?

Answer 22

Network layer

Question 23

Where does a computer get the MAC address?

Answer 23

It is built into the network interface card (NIC)

Question 24

Which protocol is connectionless?

a) TCP
b) UDP
c) Port number
d) Well-known port

Answer 24

b) UDP (User Datagram Protocol)

Question 25

The OSI model has ____ layers while the TCP/IP model has ____ layers.

Answer 25

7 and 4

Question 26

Which of the following best describes a model?

a) Multiple steps of a process converted into a single step.
b) A representation of a real object or process.
c) The expansion of a single process step into multiple steps.
d) A duplicate of real object or process.

Answer 26

b) A representation of a real object or process.

Question 27

What is a chunk of data that has been sent out of a NIC (Network Interface Card) called?

Answer 27

Frame