Fundamentals of Computer Networks Flashcards

1
Q

What is a computer network?

A

Two or more interconnected computers - may be connected either wired or wirelessly.

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2
Q

What are the benefits of computer networks?

A
  • Communication is easier
  • Can use computers anywhere in the world to access their info (if stored on a network)
  • Easier to store files and info over a network
  • Easier to share resources
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3
Q

What are the risks of computer networks?

A

Expensive hardware
Risk of viruses + hacking
Specialist staff often required (setting up complicated network).
(Dependence) users relying on a network might be stuck without access to it.

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4
Q

Describe what a Personal Area Network is.

A

A personal area network is that is used for data transmission amongst devices.

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5
Q

Describe what a Local Area Network is.

A

A local area network is a network of computers within the same building.

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6
Q

Describe what a Wide Area Network is.

A

A wide area network is a network that spans across a building, buildings or countries.

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7
Q

What is a wired network?

A

Computers can be connected through Ethernet cables which connect to the Ethernet port.

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8
Q

What is a wireless network?

A

A wireless connection that uses radio signals to send data across networks.

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9
Q

What are the benefits of wireless networks as opposed to wired networks?

A

Users can move around freely within the area of network with their devices and get an internet connection.
Users can share files and other resources connected to the network without being connected to a port.
Saves expense, time and inconvenience of having to lay cables.
Easier to add new device as no new cabling is required.
Instant transfer of data is quicker.

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10
Q

What are the disadvantages of wireless networks as opposed to wired networks?

A

File transfer speeds are generally slower
Can be obstructed by walls, ceilings and furniture
Are generally less secure and easier to hack into

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11
Q

Explain the star topology.

A

When all of the computers have their own cable connecting them to a switch, which routes messages to the correct computer. A powerful computer called the server controls the network.

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12
Q

Explain the bus topology.

A

Computers are connected to a single backbone.

They all share this cable to transmit to each other and each message is divided into frames.

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13
Q

What is a protocol?

A

Set of rules that define how devices communicate.

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14
Q

What is a Network Interface Card?

A

All devices connecting to the internet need an NIC.

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15
Q

What is a Network Interface Card?

A

All devices connecting to the internet need an NIC. Required to connect any network-enabled device. It is a physical component which can either operate wirelessly or have a wired connection using a standard Ethernet cable.

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16
Q

What is a MAC address?

A

Each NIC had a unique media access control, which is assigned and hardcoded into the card (by manufacturer) and uniquely identifies device. Address is 49 bits long and written as 12 hex digits.

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17
Q

What is Wi-Fi?

A

Wireless fidelity is a family of protocols or rules that make wireless networking run smoothly.

18
Q

What are the risks of wireless networks?

A

Criminal activity - an unauthorised user can use the wireless connection to hack into the network and cause damage by planting viruses, or bring the network to a halt by flooding it with useless traffic.
Bandwidth stealing - outside intruders slow the network down by using the internet to download games, music + other software.
Confidentiality - if any network infor isn’t encrypted before transmission, an intruder can gain access to confidential info.

19
Q

What is Ethernet?

A

Family of networking rules/protocols widely used in LANs.

20
Q

What is the Ethernet protocol?

A

Describes how devices should format data ready for transmission between computers on the same network. Used to change the format of data if it is not in the right format.

  • Nodes wait until connection is quiet, then attempt to ‘speak’ or transmit.
  • 2 nodes attempting to transmit simultaneously stop and wait a random period before reattempting.
21
Q

Explain the purpose and use of the Wi-Fi protocol.

A

Allows electronic devices to connect to a wireless LAN. Wi-Fi compatible devices can connect to the Internet via a WLAN and Wireless Access Point (WAP).

22
Q

How does the Wi-Fi protocol work?

A

WAP receives data from network via its physical location.
Transmitter converts data into radio waves which are then transmitted.
Any device on network receives this radio signal via a Wi-Fi adaptor - allows it to communicate or download data from data source.
Works in reverse direction when device wishes to send data over network to another computer.

23
Q

Explain the purpose and use of the TCP (Transmission Control Protocol) protocol.

A

A standard that defines how messages are broken up into packets and reassembled at the destination. Also detects errors and and resends lost packets.

24
Q

Explain the purpose and use of the UDP (User Datagram Protocol) protocol.

A

Uses a simple connectionless transmission model and an alternative to TCP, but has no error checking or correction.

25
Q

Explain the purpose and use of the IP (Internet Protocol) protocol.

A

Identifies the location of a device on the internet and routes the individual packets from source to destination via routers.

26
Q

Explain the purpose and use of the HTTP (Hypertext Transfer Protocol) protocol.

A

Used for accessing and receiving web pages in the form of HTML (Hypertext Markup Language) files in the internet.
The protocol requests the web server to transmit the requested web page to the user’s browser for viewing.

27
Q

Explain the purpose and use of the HTTPS (Hypertext Transfer Protocol Secure) protocol.

A

Serves same purpose as HTTP but encrypts info so that it can’t be understood of hacked.

28
Q

Explain the purpose and use of the FTP (File Transfer Protocol) protocol.

A

Used when transferring computer files between a client and server on a computer network.
It’s a client-based model and uses separate control and data connections between the client and the server.

29
Q

Explain the purpose and use of the SMTP (Simple Mail Transfer Protocol) protocol.

A

Protocol for sending e-mail messages between servers and used for sending out email from an email client.

30
Q

Explain the purpose and use of the IMAP (Internet Message Access Protocol) protocol.

A

Stores email messages on a server but allows users to view and manipulate the messages as though they were stored locally on their own computers.

31
Q

Why is Network Security needed and why is it important?

A

To keep unauthorised people from accessing resources and to ensure that authorised people can access the resources they need.
-Important to prevent unauthorised access to data, misuse or modification of data.

32
Q

Explain authentication as a method of security.

A

Ways of identifying a genuine, authorised user.
Password Protection - easiest way to stop unauthorised access to computers or files is to use a combination of a username and password.

33
Q

Explain encryption as a method of security.

A

Used to protect data and prevent it from being hacked or accessed illegally.
Makes the data unreadable unless the recipient has the necessary decryption tools.

34
Q

Explain firewall as a method of security.

A

Designed to prevent unwanted internet traffic from gaining access to the LAN.
Unauthorised users external to the network are blocked by the firewall.

35
Q

Explain MAC address filtering as a method of security.

A

Every computing device has a unique MAC address, so it is possible to use MAC filtering on a wireless network to determine which devices are allowed access to a network.

36
Q

List the 4 layers in a TCP/IP model.

A

Application Layer
Transport Layer
Network Layer
Link Layer

37
Q

Describe the Application Layer in the TCP/IP model.

A

Where the network applications operates. The data being sent is encoded so that it is understandable by the recipient.
This means formatting data and adding appropriate header according to a protocol being used, e.g. HTTP, HTTPS, FTP, IMAP and SMTP.

38
Q

Describe the Transport Layer in the TCP/IP model.

A
  • Sets up the communication between two hosts and establishes settings (e.g. “language” and size of packets).
  • Splits data into packets and adds packet info
  • Hides different network topologies and architectures. TCP and UDP operate on this layer.
39
Q

Describe the Network Layer in the TCP/IP model.

A
  • Addresses and packages data for transmission , and routes the packet across the network.
  • Attaches the IP address of the sender so the recipient will know who sent it.
  • Attaches the destination IP address as well - IP operates on this layer.
40
Q

Describe the Link Layer in the TCP/IP model.

A
  • Where network hardware (such as NIC) is located.
  • OS device drivers also sit here - allows the MAC addresses of the sender and the recipient, allowing the packet to be directed to a specific device on a LAN, for example.