GOOGLE IT SUPPORT PROFESSIONAL CERTIFICATE

Course 2 – The Bits and Bytes Of Computer Networking

Week 1: Introduction to Networking

Coursera Study Guide

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TABLE OF CONTENT

Welcome to the Networking course of the IT Support Professional Certificate! In the first week of this course, we will cover the basics of computer networking. We will learn about the TCP/IP and OSI networking models and how the network layers work together. We’ll also cover the basics of networking devices such as cables, hubs and switches, routers, servers and clients. We’ll also explore the physical layer and data link layer of our networking model in more detail. By the end of this module, you will know how all the different layers of the network model fit together to create a network.

Learning Objectives

  • Describe how the TCP/IP five layer network model works.
  • Identify basic networking devices.
  • Label each of the five layers in the TCP/IP network model.
  • Describe how the physical layer works.
  • Describe how the data link layer works.

PRACTICE QUIZ: TCP/IP

1. Which of the following is an example of a network layer (layer 3) protocol?

  • IP (CORRECT)
  • Ethernet
  • UDP
  • TCP

Nice job! IP, or Internet Protocol, is the most common network layer protocol.

2. What’s the difference between a client and a server?

  • A client requests data, and a server responds to that request. (CORRECT)
  • Clients operate on the data link layer, and servers operate on the network layer.
  • Clients and servers are different names for the same thing.
  • A server requests data, and a client responds to that request.

Wohoo! You’re correct.

3. Which of the following are examples of layers of our five-layer network model? Check all that apply.

  • The physical layer (CORRECT)
  • The application layer (CORRECT)
  • The presentation layer
  • The transport layer (CORRECT)

Great work!

PRACTICE QUIZ: NETWORKING DEVICES

1. Which of the following statements accurately describe the differences between a hub and a switch? Check all that apply.

  • A hub causes larger collision domains. (CORRECT)
  • A switch remembers which devices are connected on each interface, while a hub does not. (CORRECT)
  • A hub is a physical layer device, and a switch is a data link layer device. (CORRECT)

You got it! Hubs are more sophisticated versions of switches.

2. What does LAN stand for?

  • Local area network (CORRECT)
  • Locally available network
  • Little area network
  • Large area network

That’s right! LAN stands for Local Area Network.

3. What’s a router?

  • A more advanced version of a switch
  • A device that knows how to forward data between independent networks.  (CORRECT)
  • A network device used specially for fiber cables
  • A physical layer device that prevents crosstalk

Awesome work! A router connects independent networks by forwarding data between them.

PRACTICE QUIZ: THE PHYSICAL LAYER

1. What is the type of modulation used by twisted pair cable computer networks known as?

  • Line crimping
  • Simplex communication
  • Line coding (CORRECT)
  • RJ45

You nailed it! Line coding is the modulation of an electrical charge so that each side of a connection knows what is a one and what is a zero.

2. What’s the difference between full and half duplex?

  • Full duplex is slower than half duplex.
  • Full duplex allows communications in two directions at the same time; half duplex means that only one side can communicate at a time. (CORRECT)
  • Full duplex is a form of simplex communications.
  • Half duplex occurs when hubs are in use; full duplex occurs when switches are in use.

Nice job! A half-duplex connection allows communication in both directions, but only one side can communicate at a time.

PRACTICE-QUIZ: THE DATA LINK LAYER

1. How many octets are there in a MAC address?

  • 8
  • 4
  • 5
  • 6 (CORRECT)

Great work! A MAC address is a 48-bit number consisting of 6 octets.

2. What address is used for Ethernet broadcasts?

  • FF:FF:FF:FF:FF:FF (CORRECT)
  • 00:00:00:00:00:00
  • FF:00:FF:00:FF:00
  • 11:11:11:11:11:11

Excellent! The address FF:FF:FF:FF:FF:FF is used for Ethernet broadcast traffic.

3. What is a cyclical redundancy check?

  • A mathematical calculation used to ensure that all data arrived intact (CORRECT)
  • The actual data being transported by an Ethernet frame
  • A way for two computers to synchronize their clocks
  • A technique that allows for multiple logical LANs to operate on the same equipment

Yep! A cyclical redundancy check ensures that there was no data corruption.

QUIZ: LAYERS IN NETWORKING MODELS

1. Let’s test your knowledge of the five-layer networking model presented in this course!

Step 1: Drag-and-drop a networking layer into the correct order on the right-hand side of the screen. Do this for all five layers represented. If you make a mistake, click the ‘Reset’ button to try again.

Step 2: After you’ve identified the five networking layers, you will be presented with a networking hardware component. This component represents a different item in the networking model. Like you did in Step 1, drag-and-drop these into the correct order. If you make a mistake, click the ‘Reset’ button to try again.

Step 3: When you’re done, close the quiz (if in fullscreen) and click the “Submit Quiz” button to earn a grade.

Good luck!

Course 2 Week 1.1
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Course 2 Week 1.2
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CORRECT! You may proceed to the second part of the quiz.

Course 2 Week 1.3
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Course 2 Week 1.4
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Correct: Well done! You have matched the hardware components to their corresponding network layers. You may now continue and submit the quiz.

QUIZ: NETWORKING BASICS

1. A network segment where only one device can communicate at a time is known as a _____.

  • cross talk
  • protocol
  • collision domain (CORRECT)
  • modulation

Great job! A collision domain is the term used to describe a network segment where collisions may occur — that is, a network segment where only one device can successfully communicate at a time.

2. The transmission method that sends data to every device on a LAN is known as a _____ transmission.

  • broadcast (CORRECT)
  • unicast
  • multicast
  • simulcast

Awesome! Broadcast transmissions are used to communicate with every node on a network segment.

3. Something that requests data from a server is known as a ____.

  • switch
  • router
  • server
  • client (CORRECT)

Yep! A client requests data, and a server responds to that request.

4. A device that connects lots of devices and remembers which ones are connected to each interface is known as a _____.

  • hub
  • switch (CORRECT)
  • router
  • server

Great work! By remembering which devices are connected to each interface, a switch reduces collision domains.

5. A defined set of standards that computers must follow in order to communicate properly is known as a _____.

  • switch
  • collision domain
  • modulation
  • protocol (CORRECT)

Good job! Protocols help define standards so that different computers can communicate with each other.

6. What layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for defining a way to interpret signals so network devices can communicate?

  • Data link (CORRECT)
  • Network
  • Transport
  • Application

Nice job! The data link layer is responsible for defining a common way of interpreting signals so network devices can communicate.

7. A user has multiple web pages open and is using email. Which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for sorting the data to send email and web pages to the appropriate location?

  • Data link
  • Transport (CORRECT)
  • Application
  • Network

Well done! The transport layer is responsible for sorting out which client and server programs are supposed to get data.

8. What type of cable communicates binary data by changing the voltage between two ranges?

  • Fiber
  • Gold
  • Copper (CORRECT)
  • Silver

Awesome! Copper cables communicate binary data across wires by changing the voltage between two ranges.

9. Multiple systems try to send data at the same time. The electrical pulses sent across the cable interfere with each other. What type of network segment is being used?

  • Local Area Network (LAN)
  • Wide Area Network (WAN)
  • Collision domain (CORRECT)
  • Subnet

You got it! A collision domain is a network segment where only one device can communicate at a time.

10. What device forwards data and operates at layer three of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

  • Client
  • Switch
  • Hub
  • Router (CORRECT)

Woohoo! A router is a device that knows how to forward data between independent networks and operates at layer three.

11. How many wires are in a standard Category 6 cable?

  • 4
  • 10
  • 6
  • 8 (CORRECT)

You nailed it! A standard Cat6 cable has 8 wires that consist of four twisted pairs inside of a single jacket.

12. Select the device that will have the most network ports.

  • Laptop
  • Server
  • Desktop
  • Switch (CORRECT)

You got it! A switch will have the most network ports, because its purpose is to connect many devices.

13. What is used to determine when the communications channels are clear and when a device is free to transmit data?

  • Carrier Sense Multiple Access with Collision Detection (CSMA/CD) (CORRECT)
  • Ethernet
  • Transmission Control Protocol (TCP)
  • Internet Protocol (IP)

You nailed it! Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is used to determine when the communications channels are clear and when a device is free to transmit data.

14. A user is operating Client A and sends a message to Client B. What is used to identify the node the transmission is meant for?

  • Media Access Control (MAC) address (CORRECT)
  • Ethernet address
  • Subnet address
  • Internet Protocol (IP) address

Awesome! A MAC address is a globally unique identifier attached to an individual network interface.  A MAC is used to identify which node the transmission is meant for.

15. What section in an ethernet frame will you find a Virtual Local Area Network (VLAN) header?

  • Preamble
  • Frame Check Sequence
  • Payload
  • EtherType field (CORRECT)

Woohoo! You may find a VLAN header in the EtherType field.  This will indicate that the frame is called a VLAN frame.

16. Which section in an ethernet frame contains the data from higher layers, such as Internet Protocol (IP) and the transport and application layers?

  • EtherType
  • Payload (CORRECT)
  • Preamble
  • Frame Check Sequence

Well done! The payload contains all of the data from higher layers, such as the IP, transport, and application layers, that’s actually being transmitted.

17. A device that knows how to forward traffic between independent networks is known as a _____.

  • Router (CORRECT)
  • switch
  • hub
  • node

Correct: Awesome! A router is used to forward data across multiple networks.

18. MAC address stands for ____ address.

  • media access control (CORRECT)
  • message authentication check
  • maximum allowable cost
  • memory access controller

Correct: You nailed it! A MAC address is sometimes also referred to as a hardware address.

19. The most common data link layer protocol for wired connections is _____.v

  • Ethernet (CORRECT)
  • BGP
  • TCP
  • UDP

Correct: You got it! The most common data link layer protocol you’ll run into is Ethernet.

20. TCP stands for ______.

  • Transmission Control Protocol (CORRECT)
  • Tapioca Coconut Pudding
  • Translational Carrier Pathway
  • Topical Control Pathogen

Correct: Correct! Transmission Control Protocol is one of the more common transport layer protocols.

21. Which layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for delivering data between two nodes?

  • Data link
  • Network (CORRECT)
  • Application
  • Transport

Correct: You nailed it! The network layer is responsible for sending data between two nodes.  The transport layer sorts out which client and server programs are supposed to get the data.

22. You have installed a device at the physical layer. All of the systems you connect to this device will talk to each other at the same time. What have you installed?

  • Switch
  • Hub (CORRECT)
  • Router
  • Server

Correct: Right on! A hub is a physical layer device that allows for connections from many computers at once.

23. You open a web page and log into your email. The traffic travels over many routers. What protocol will the routers use to determine the most optimal path to forward the traffic?

  • Border Gateway Protocol (BGP) (CORRECT)
  • User Datagram Protocol (UDP)
  • Transmission Control Protocol (TCP)
  • Internet Protocol (IP)

Correct: Nice job! Border Gateway Protocol (BGP) lets routers learn about the most optimal paths to forward traffic.

24. You get in your car after work and turn on the radio. What type of communication does the radio use?

  • Twisted
  • Half duplex
  • Simplex (CORRECT)
  • Full duplex

Correct: You nailed it! A radio provides one way communication, or unidirectional.  This is simplex communication.

25. A Local Area Network (LAN) uses Category 6 cabling. An issue with a connection results in a network link degradation and only one device can communicate at a time. What is the connection operating at?

  • Half Duplex (CORRECT)
  • Partial
  • Simplex
  • Full Duplex

Correct: You nailed it! A full duplex connection that has a connection issue will report itself to be operating as half duplex.

26. A communications closet has a device that contains 48 ports. The device’s sole function is to provide the ports. What type of device is in the closet?

  • Switch
  • Hub
  • Router
  • Patch panel (CORRECT)

Correct: Great work! A patch panel is a device containing many network ports, but it does no other work.

27. You need to identify the manufacturer of a network interface. Where will you look for this information?

  • The fourth octet of a Media Access Control (MAC) address
  • The last octet of a Media Access Control (MAC) address
  • The first octet of a Media Access Control (MAC) address
  • The first three octets of a Media Access Control (MAC) address (CORRECT)

Correct: You nailed it! The first three octets of a MAC address are known as the Organizationally Unique Identifier (OUI).  These are assigned to individual hardware manufacturers.

28. What type of transmission will have a zero in a special bit in the destination Media Access Control (MAC) address?

  • Broadcast
  • Singlecast
  • Multicast
  • Unicast (CORRECT)

Correct: Awesome! A unicast transmission uses the Ethernet level to look at a special bit in the destination MAC address.  If the least significant bit in the first octet of a destination address is set to zero, it means that the ethernet frame is intended for only the destination address.

29. When data can flow across a cable in both directions, this is known as _____ communication.

  • ethernet
  • simplex
  • cross talk
  • duplex (CORRECT)

Correct: Wohoo! Duplex communication occurs when data flows in both directions.

30. UDP stands for ______.

  • Unified Data Pathway
  • Unknown Data Protocol
  • Universal Data Protocol
  • User Datagram Protocol (CORRECT)

Correct: Right on! User Datagram Protocol is one of the more common transport layer protocols.

31. What is the fifth layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

  • Transport
  • Data link
  • Network
  • Application (CORRECT)

Correct: Great work! The fifth layer of the TCP/IP model is the application layer.  The application layer focuses on application specific protocols.

32. Where is the Start Frame Delimiter (SFD) found in an ethernet frame?

  • The first byte of the preamble
  • The last byte of the EtherType field
  • The first byte of the EtherType field
  • The last byte of the preamble (CORRECT)

Correct: You nailed it! The SFD is found in the last byte of the preamble, and signals to a receiving device that the preamble is over, and that the actual frame contents will now follow.

33. When an electrical pulse on one wire is accidentally detected on another nearby wire, this is known as _____.

  • duplex communication
  • preamble
  • cross talk (CORRECT)
  • multicast 

Correct: Nice job! Crosstalk is reduced by the way that wires are twisted inside of a cable.

34. What layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model does IP use?

  • Data link
  • Physical
  • Transport
  • Network (CORRECT)

Correct: You got it! The network layer is also sometimes called the internet layer.  The most common protocol used at this layer is Internet Protocol (IP).

35. The Ethernet protocol functions at which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?

  • Transport
  • Physical
  • Data link (CORRECT)
  • Application

Correct: You nailed it! A lot of protocols exist at the data link layer, but the most common is Ethernet.

36. A user logs on to a laptop and opens her email. What device will provide emails to the laptop?

  • Hub
  • Switch
  • Server (CORRECT)
  • Router

Correct: Right on! A server is anything that provides data to a client.

37. What process sends ones and zeroes across network cables?

  • Lines
  • Coding
  • Bits
  • Modulation (CORRECT)

Correct: Woohoo! Ones and zeroes are sent across network cables through a process called modulation.

38. Which layer abstracts away the need for any other layers to care about what hardware is in use?

  • Transport
  • Network
  • Data link (CORRECT)
  • Physical

Correct: Well done! One of the primary purposes of the data link layer is to essentially abstract away the need for any other layers to care about the physical layer and what hardware is in use.

39. The technique that allows you to have multiple logical LANs operating on the same physical equipment is known as a _____.

  • collision domain
  • VLAN (CORRECT)
  • data link layer
  • protocol

40. Which two protocols work at the transport layer and ensures that data gets to the right applications running on those nodes?

  • Internet Protocol (IP)
  • User Datagram Protocol (UDP) (CORRECT)
  • Transmission Control Protocol (TCP) (CORRECT)
  • Dynamic Host Configuration Protocol (DHCP)

41. What does the letter B represent in a Media Access Control (MAC) address?

  • 10
  • 15
  • 11 (CORRECT)
  • 9

42. What is the most common plug used with twisted pair network cables?

  • Registered Jack 46
  • Registered Jack 11
  • Registered Jack 35
  • Registered Jack 45 (CORRECT)

43. What immediately follows the Start Frame Delimiter in an ethernet frame?

  • Payload
  • Destination Media Access Control (MAC) address (CORRECT)
  • EtherType field
  • Frame Check Sequence

44. The number system that has 16 numerals is known as _____.

  • binary
  • octal
  • hexadecimal (CORRECT)
  • decimal

Correct: You nailed it! A radio provides one way communication, or unidirectional.  This is simplex communication.

45. What process sends ones and zeroes across network cables?

  • Modulation (CORRECT)
  • Bits
  • Coding
  • Lines

Correct: You nailed it! A radio provides one way communication, or unidirectional.  This is simplex communication.

46. The first part of an Ethernet frame is known as the _____.

  • frame check sequence
  • data packet
  • preamble (CORRECT)
  • MAC address

Correct: You nailed it! A radio provides one way communication, or unidirectional.  This is simplex communication.

47. A system has defined specifications that describe how signals are sent over connections. Which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model provides this function?

  • Transport
  • Network
  • Data link
  • Physical (CORRECT)

48. What will allow you to form point-to-point networking connections?

  • Router
  • Cables (CORRECT)
  • Switch
  • Hub
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