Week 1: Introduction to Networking
Introduction to Detection and Incident Response
Welcome to the Networking part of the complete IT Support Professional Certificate! This first week is where essential concepts of computer networking will be introduced to you. You will learn about the TCP/IP and OSI networking models and how their layers work harmoniously. We’ll be looking into the important network devices, such as cables, hubs, switches, routers, servers, and clients, but then we’ll dive deeper into the physical and data link layers of the model. By the end of the module, you will understand how these different layers of the network model work together to create a network.
Learning Objectives:
- Understand how the TCP/IP five-layer network model works.
- Identify key networking devices.
- Label each of the five layers in the TCP/IP network model.
- Explain how the physical layer operates.
- Explain how the data link layer operates.
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! Yes, technically hub and switch are used as control devices in a communication network, but they are different from each other in their tasks and functioning.
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! Yes, that’s correct! A router is a network device that connects multiple independent networks and forwards data packets between them. It operates at the network layer (Layer 3) of the OSI model.
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 method employed to modulate an electric signal such that it can be differentiated between ‘1’ and ‘0’ at both ends of the connection.
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! All parties can communicate with each other in both directions, but only one can transmit for each half-duplex connection.
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!
CORRECT! You may proceed to the second part of the quiz.
Correct: I appreciate it! Wishing you lots of luck as you carry on with your quiz submission! Do let me know if you need anything else.
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! Collision domain indicates the network segment where collision occurs and where only one device can transmit at a time successfully.
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 transmission is the method whereby a message is sent to all nodes within a segment of a network.
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! A switch minimizes the number of collision domains through keeping track of connected devices at each interface.
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! The setting of standards for communicating computers is done through the protocols.
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! Allowing all network devices to communicate with one another, This layer is responsible for establishing common rules for interpreting signals.
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! It is the transport layer which is responsible for deciding which client and server programs should receive the data.
8. What type of cable communicates binary data by changing the voltage between two ranges?
- Fiber
- Gold
- Copper (CORRECT)
- Silver
Awesome! Binary data is transmitted through copper cables by changing the voltage levels 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! The device that interconnects different networks and makes communication by forwarding data is known as a router, which works in the network layer 3.
11. How many wires are in a standard Category 6 cable?
- 4
- 10
- 6
- 8 (CORRECT)
You nailed it! A standard Cat6 cable is an 8-wire wiring scheme formed into four twisted pairs, all fitted in a single jacket.
12. Select the device that will have the most network ports.
- Laptop
- Server
- Desktop
- Switch (CORRECT)
You got it! Moreover, it generally has quite a number of network ports because it serves one of the purposes as connecting the 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! It is called Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which listens to the communication channel, enabling a device to conditionally send the intended data.
6. What can an intrusion detection system (IDS) do? Select three answers.
- Stop intrusive activity
- Monitor system and network activity (CORRECT)
- Collect and analyze system information for abnormal activity (CORRECT)
- Alert on possible intrusions (CORRECT)
IDS is an application that keeps track of system and network activities and generates alerts for suspected intrusions. It also retrieves and analyzes system data to detect any abnormal or unusual behavior.
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! Basically, a Mac address is a unique identifier attached to a network interface that is use for designating the destination for a transmission.
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! Frame types can be differentiated using the EtherType field, which shows that the frame is of VLAN type.
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! Such payloads are the ones that encapsulate all higher-level data-from IP to transport to the application level-in transit.
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: Of course! Yes, the TCP protocol is one of the most largely used 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 got it! The network layer handles the actual sending of data between two nodes, whereas the transport layer guarantees that the data reaches the correct client and server applications.
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: Correct! It is a physical-layer device that allows multiple computers to join a network simultaneously.
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: Much obliged! That’s right: The Border Gateway Protocol (BGP) is concerned with allowing routers to learn about and transmit traffic over the best paths through different networks.
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: Thanks! That’s correct, if a full-duplex connection had a problem then it could fall back to half-duplex and mention that change.
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: Thanks! Exactly-The first three of the six octets of a MAC address are known as the Organizationally Unique Identifier (OUI) and are assigned to specific hardware manufacturers for the unique identification of their devices.
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: Thank you! You’re totally right. It is unicast transmission at the Ethernet level when the least significant bit of the first octet is checked in the destination MAC address. If it ends up being a zero, then the Ethernet frame can be directed to, say, a single, specific 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: Definitely: the User Datagram Protocol (UDP) is also one of the more generally adopted transport layer protocols, commonly known for its simplicity and low overhead despite not guaranteeing reliable delivery like TCP.
31. What is the fifth layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?
- Transport
- Data link
- Network
- Application (CORRECT)
Correct: Thanks! I hear you: the application layer-my fifth layer in the TCP/IP model-is where applications-specific protocols are published for enabling communications via software applications to the network.
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: Indeed! The start frame delimiter— SDF, is positioned within the last byte of the preamble marking the termination of the preamble and initiation of the actual frame contents.
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: Absolutely! Cross-talk is minimized by twisting the wires together inside a cable, which reduces interference between the signals of different wires.
34. What layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model does IP use?
- Data link
- Physical
- Transport
- Network (CORRECT)
Correct: You’re right! The network layer is the same as the internet layer; the most frequently used protocol of 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: For sure! There are other protocols at the data link layer, but Ethernet is by and large the most common and frequently used protocol for local area network communication.
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: Absolutely! You’re right: ones and zeroes are sent down network cables as a result of modulation, where some electrical signals are converted into a numerical data stream for transmission purposes.
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: I’m grateful! You’ve got it absolutely spot-on. The data link layer abstracts from the details of the physical layer so that higher layers can communicate without having to worry about specific hardware or physical transmission methods 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: True that! A radio creates a one-way communication, thereby endowing it with the properties of simplex communication.
45. What process sends ones and zeroes across network cables?
- Modulation (CORRECT)
- Bits
- Coding
- Lines
Correct: “Thank you! Yes, that’s right; a radio does simplex communication, which is one-way, unidirectional between the transmitter and the receiver.
46. The first part of an Ethernet frame is known as the _____.
- frame check sequence
- data packet
- preamble (CORRECT)
- MAC address
Correct: Thank you! You are indeed correct. Radio communication is simplex communication in that it transmits data only in one direction.
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