The 7 Layers of the OSI Model

Question 1

Why does networking exist in the first place?

Answer 1

To allow one device or person to speak with another device or person in another location.

Question 2

Do the individual OSI layers care about the way other layers work?

Answer 2

No, only that the inputs and outputs are as expected

Question 3

What does the physical layer concern itself with?

Answer 3

The ingestion of data.

Question 4

How does the physical layer work?

Answer 4

Through a predefined electrical format such as voltage and frequency.

Question 5

At what layer can one machine talk directly to another machine?

Answer 5

At the datalink layer.

Question 6

What is the hardware address called that each machine or network interface have?

Answer 6

the MAC address

Question 7

What does MAC stand for?

Answer 7

Media access control

Question 8

What is the data encapsulation at the datalink layer called?

Answer 8

Frames

Question 9

What types of information are contained in a frame

Answer 9

source and destination MAC address

Question 10

At what layer is sequencing and flow control handled?

Answer 10

datalink

Question 11

What is sequencing and flow control?

Answer 11

Controls transmission speeds and sequencing of data packets.

Question 12

What layer handles error correction?

Answer 12

Datalink

Question 13

What is error correction?

Answer 13

Datalink knows when data is damaged at the physical layer, and can resend the corrected packet(s).

Question 14

What is the data encaspulation at the network layer?

Answer 14

Packets

Question 15

What adressing is used at the network layer?

Answer 15

IP addresses

Question 16

Does the networking layer handle error checking?

Answer 16

No.

Question 17

What are some common protocols used at the networking layer?

Answer 17

IP
IPX
ICMP

Question 18

What is the data encaspulation at the transport layer?

Answer 18

data segments

Question 19

At what layer is host to host flow control added?

Answer 19

At the transport layer

Question 20

True or false: Transport layer provides some error correction?

Answer 20

True, only in some cases.

Question 21

What common protocols are used at the transport layer?

Answer 21

TCP

UDP

Question 22

What transport layer protocol is designed for reliability over speed?

Answer 22

TCP

Question 23

What transport layer is designed for speed over reliability?

Answer 23

UDP

Question 24

When would TCP be used?

Answer 24

where accurate data is required, such as requesting a web page, or downloading a file.

Question 25

When might UDP be used?

Answer 25

Where datapackets can be lost, such as Voice over Internet.

Question 26

At what layer allows for ongoing connection of communication between to machines?

Answer 26

At the session layer.

Question 27

At what layer are communication ports opened? (Think ports in security groups)

Answer 27

At the session layer.

Question 28

What common protocols are used in the session layer?

Answer 28

``` TCP/IP AT (used by HTTP) UDP 53 (used by DNS) ```

Question 29

At what layer to services understand the protocols being used?

Answer 29

At the application layer

Question 30

What are the processes known as that allow one layer to submit information to another?

Answer 30

Data encapsulation | Data de-encapsulation

Question 31

What protocol is used to discover the IP address associated to a MAC address?

Answer 31

ARP - Address Resolution Protocol

Question 32

What is does a fully encapsulated packet look like?

Answer 32

| data || TCP Header || IP || RMAC |

Question 33

What is Layer 1?

Answer 33

Physical

Question 34

What is layer 2?

Answer 34

Datalink

Question 35

What is layer 3?

Answer 35

Network

Question 36

What is layer 4?

Answer 36

Transport

Question 37

What is layer 5?

Answer 37

Session

Question 38

What is layer 6?

Answer 38

Presentation

Question 39

What is layer 7?

Answer 39

Application