Layers

Question 1

What are the 7 layers of the OSI Model?

Answer 1

L7 Application
L6 Presentation
L5 Session
L4 Transport
L3 Network
L2 Data Link
L1 Physical

Question 2

Name some protocols and services that run at L7 (Application Layer)?

Answer 2

Email Protocols SMTP and Pop3
Telnet
HTTP
File Transfer Protocol( FTP)
Simple Network Management Protocol (SNMP)

Question 3

Name the four primary tasks that the Presentation Layer is concerned with.

Answer 3

1. Compatibility with the operating system.
2. Proper encapsulation of data for network transmission.
3. Data formatting (ASCII, Binary)
4. Data encryption, compression and translation

Question 4

What is the Application Layer (L7)?

Answer 4

It’s where the end users interact with the network.

Question 5

What is the Presentation Layer (L6)?

Answer 5

How the data is presented.

Question 6

What are some file types in the Presentation Layer?

Answer 6

JPEG, ASCII, GIF, MPEG, MIDI, EBCDIC, and TIFF

Question 7

What is the Session Layer (L5)?

Answer 7

It handles the creation, maintenance and teardown of communications between those two hosts.

Question 8

What is the Transport Layer (L4)?

Answer 8

It establishes a logical end-to-end connection between two systems, segment data received from the upper layers of the OSI model, and to make sure the data gets to the destination in the correct order and free of errors.

Question 9

What are the two methods for transporting data?

Answer 9

Connection-oriented, referring to TCP and connectionless, referring to UDP.

Question 10

Besides TCP and UDP, what is also a Transport Layer?

Answer 10

SPX (Sequenced Packet Exchange) NCP (Novell Netware protocol.

Question 11

The Network Layer (L3) is also called what?

Answer 11

The Routing Layer

Question 12

What layer does IP run at?

Answer 12

The Network Layer

Question 13

What is the two-question process in the Network Layer?

Answer 13

What valid paths exist from the local router to a given destination?
What is the best path (optimal path) to take to get there?

Question 14

What layer is the Data Link?

Answer 14

L2

Question 15

What is a WAP?

Answer 15

Wireless Access Points

Question 16

What runs at L2?

Answer 16

Cable Modems and DSL Modems

Question 17

What four major specifications run at L2?

Answer 17

Ethernet
High Data Link Control (HDLC)
Point-to-Point Protocol (PPP)
Frame Relay

Question 18

What is HDLC?

Answer 18

High Data Link Control

Question 19

What is PPP?

Answer 19

Point-to-Point Protocol

Question 20

Does the Data Link Laer perform error detection?

Answer 20

Yes

Question 21

The Data Link Layer performs error detection through the what?

Answer 21

The Frame Check Sequence

Question 22

MAC addresses are sometimes called what?

Answer 22

hardware addresses and physical addresses

Question 23

What is a burned-in address?

Answer 23

MAC address that is physically burned into the Network Interface Card (NIC)

Question 24

What does NIC stand for?

Answer 24

Network Interface Card

Question 25

What does BIA stand for?

Answer 25

a burned-in address

Question 26

Physical addresses are used in what layer?

Answer 26

Data Link Layer

Question 27

A physical address is used to deliver?

Answer 27

A frame, not a physical layer address

Question 28

Physical cable, pins, Connectors and the electrical current, run at which layer?

Answer 28

Physical Layer

Question 29

Which layers is the data simply called data?

Answer 29

Application, Presentation and Session Layers

Question 30

Which layer is data placed into segments?

Answer 30

Transport Layer

Question 31

What layer is data placed into packets?

Answer 31

Network Layer

Question 32

What layer is data placed into frames?

Answer 32

Data Link Layer

Question 33

What layer takes the form of bits?

Answer 33

Physical Layer

Question 34

Which layer is all ones and zeros?

Answer 34

Physical Layer

Question 35

Which layer adds a header and a trailer?

Answer 35

L2 Data Link Layer

Question 36

What does PDU stand for?

Answer 36

Protocol Data Unit

Question 37

What is a Protocol Data Unit?

Answer 37

A combination of data and layer-specific header.