Module 1: Networking Models Flashcards
List the 7 layers of the OSI model in the correct order – from layer 7 to layer 1
Application, Presentation, Session, Transport, Network, Datalink, Physical
Explanation: One of the easiest ways to memorize the layers of the OSI model is to remember the phrase “Please Do Not Throw Sausage Pizza Away”. The only twist here is that you were asked to produce them in reverse order.
Which layer of the OSI model is equivalent to the Internet layer of the TCP/IP model?
A. Transport
B. Network
C. Session
D. Application
B (Network)
Explanation: There are only 4 layers in the TCP/IP models versus 7 layers in the OSI model. Because the TCP/IP model is seldom referenced it is a good idea to memorize the two models compared side by side.
Which layer of the OSI model provides flow control and both reliable and unreliable methods of communication?
A. Transport
B. Session
C. Network
D. Presentation
A. (Transport)
Explanation: When reliable and unreliable communication is mentioned, what they are referring to is TCP (reliable) and UDP (unreliable). TCP and UDP are layer 4 protocols and therefore reside in the Transport layer.
Performs data encryption/decryption and compression/decompression and is associated with file formats such as JPEG, MPEG, etc…
A. Application
B. Presentation
C. Session
D. Transport
B. (Presentation)
Explanation: The protocol and functions of the upper layers of the OSI model can sometimes be difficult to remember, so look for clues in the question that will hint at which layer. In this case JPEG and MPEG formats are mentioned. Most folks know these files as video and audio formats. These protocols format the data and present it to the application in the format that it needs.
Provides logical addressing and path determination/routing services.
A. Physical
B. Datalink
C. Network
D. Transport
C. (Network)
Explanation: The clues here are logical addressing (IP addressing) versus physical addressing (MAC addresses). It also mentions path determination and routing. They are describing routing. What layer do routers function at = the Network Layer.
The following protocols belong to which layer of the OSI model? FTP, Telnet, SSH, HTTP, HTTPS
A. Application
B. Session
C. Network
D. Datalink
A. (Application)
Explanation: The clue here is that all of these protocols are tools that are used in networks. These “tools” are fully functional applications designed for specific purposes. Applications live at the Application Layer.
The following protocols belong to which layer of the OSI model?
TCP, UDP, RTP, ESP
A. Physical
B. Datalink
C. Transport
D. Session
C. (Transport)
Explanation: RTP and ESP may not be familiar, but TCP and UDP should certainly be.
The following protocols belong to which layer of the OSI model?
LLC, MAC, 802.3 Ethernet, 802.11 WiFi
A. Physical
B. Datalink
C. Session
D. Presentation
B (Datalink)
Explanation: This one is probably among the easiest to figure out the OSI layer from the protocols. Layer 2 switches and Access points use MAC addresses to forward frames.
Which of the following is true?
A. Encapsulation occurs when data moves up the OSI stack,
de-encapsulation occurs when data moves down the stack.
B. Encapsulation occurs when data moves down the OSI stack,
de-encapsulation occurs when data moves up the stack.
C. Encapsulation and de-encapsulation occur at each layer as
data moves up the stack.
D. Encapsulation and de-encapsulation occur at each layer as
data moves down the stack.
B (Encapsulation occurs when data moves down the OSI stack, de-encapsulation occurs when data moves up the stack.)
Explanation: The “overhead” information is added at each layer as data moves down the OSI stack starting from the application layer. This overhead information allows the OSI layer to communicate with its peer layer on the far end.
Which of the following acronyms can be used to remember the layers of the OSI model?
(Choose four)
A. Please Do Not Throw Away Sausage Pizza
B. All People Seem To Need Data Processing
C. Please Do Not Throw Sausage Pizza Away
D. Please Do Not Teach Students Pointless Acronyms
E. People Don’t Need Those Stupid Packets Anyway
F. Please Do Not Send The People Away
B, C, D, E
(All People Seem To Need Data Processing)
(Please Do Not Throw Sausage Pizza Away)
(Please Do Not Teach Students Pointless Acronyms)
(People Don’t Need Those Stupid Packets Anyway)
Explanation: It really doesn’t matter what mnemonic you use to remember the layers of the OSI model as long as the letters in it are P-D-N-T-S-P-A (layer 1 to 7) or A-P-S-T-N-D-P (layer 7 to 1)
