Networks Flashcards

1
Q

What is a network?

A

computers which are interconnected for the purpose of exchanging data

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2
Q

What is a protocol?

A

A set of rules that determines how data is transmitted over different computers on the network. They allow devices to communicate with each other regardless of their differences.

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3
Q

What are the ways in which networks are connected?

A

They can be wired(cooper wires, electrical signal) or wireless(radio waves)

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4
Q

What is a LAN?

A
  • Local Area Network* Many computers are connected to each other and can share resources* shared services* Privately owned and operated - provides a secure and controlled environment* 1 to 10 km range
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5
Q

What is a WAN?

A
  • Wide Area Network* Many LANs joined connected which can communicate with each other* Long distance communication (>50km range)
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6
Q

What is a VLAN?

A
  • Virtual local area network* Makes it seem like computers are under one LAN* Can be between different computers in different countries
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7
Q

Why are VLANs implemented?

A

For scalability, security and ease of network management. They can quickly adapt to changes in network environments and relocation of nodes.

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8
Q

What is a SAN?

A
  • Storage Area Network* High speed network that stores and provides access to large amounts of data
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9
Q

What are some features of SANs?| 6 features

A
  • Fault tolerant - one SAN fails, data can stil be accessed* Scalable* Appears as a local drive and not a network drive* fibre channels* Unaffected by network traffic* Expensive
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10
Q

What is a WLAN?

A
  • Wireless LAN* Used to send and receive data* 50 meter range
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11
Q

What is PAN?

A
  • Personal area network* Used for communication with individuals in close proximity* 10 meter range* Bluetooth and Wifi direct
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12
Q

What is P2P?

A

Network model which allows direct exchange of files and data

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13
Q

What is NAS?

A
  • Network attached storage* Storage device on the network* Multiple hard drives* Own NIC* Connects to a router or a switch* If the NAS fails, nodes can not access it
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14
Q

Differences between internet and extranet.

A

Internet* public* less secure* accessible by anyone* large number of users can access it* not owned by anyone* general public uses it* less costlyExtranet* private* secure* username and password required* limited number of users can access it* owned by an organization* employees use it* expensive

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15
Q

What is the OSI model?

A

The open systems intercommunication model is a conceptual model that represents how communication over networks is divided

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16
Q

What are the layers in the OSI model?

A

Application layer, presentation layer, session layer, transport layer, network layer, data link layer and physical layer| “A”ll “P”eople “S”eem “T”o “N”eed “D”ata “P”rocessing

17
Q

What does the application layer do?

A

It is used by end-user software such as web browsers and email clients. It provides protocols that allow software to send and receive information and present data to users.| e.g - HTTPS, FTP, POP, SMTP, DNS

18
Q

What does the presentation layer do?

A

It prepares data for the application layer:* Data reformatting to ensure character encoding scheme is correct* Performs encyrption(data can only be decrypted and the destination node)* Data compression

19
Q

What does the session layer do?

A
  • Creates and manages session till logout* Adds checkpoints(which can be accessed if an error occurs)* Terminates session
20
Q

What does the transport layer do?

A
  • Takes data from session layer and breaks it into segments* Determines type of connection(TCP or UDP)
21
Q

What is TCP?

A

Connection oriented protocol which is reliable, slower than UDP and has error correction

22
Q

What is UDP?

A

Connectionless protocol which is unreliable, faster, no error correction but discards the packets and request to resend instead

23
Q

What is flow control?

A

The sender and receiver might be sending and receiving at different speeds, but the data is not lost

24
Q

What does the network layer do?

A

The segments are broken down into packets. The path is selected and the source and destination node IP addresses are added

25
Q

What does the datalink layer do?

A

It breaks down the packets into frames(depending on hardware) and sends them. It also adds the MAC address which keeps changing on each node

26
Q

What does the physical layer do?

A

Converts frames into raw bits(1s and 0s). It decides:* the connector* electric cable or wireless technology* bitrate* mode of communication(uni or bi directional)

27
Q

What is a VPN?

A

A virtual private network establishes a secure and reliable network connection over an unsecure network such as the internet

28
Q

How does a VPN establish a secure connection?

A

It encrypts your data and disguises your identity by hiding your IP address.

29
Q

What is tunneling?

A

An additional layer of protection on each packet added by the VPN.

30
Q

What are some applications of a VPN?

A
  • It provides a secure connection for remote workers* Provides an extra layer of protection for people who access public Wifi* Enable you to access regional restricted internet contents
31
Q

What does the term “data” mean?

A

Anything in a form suitable for use with a computer e.g binary

32
Q

What does the term “packet” mean?

A

A small unit of data used in network communication

33
Q

What does a packet contain?

A
  • Source IP address* Destination IP address* Sequence number of packets(original order of packets so they can be reassembled at the destination)* Type of service* Flags* Other technical data* Payload(the bulk of the packet where the actual data is)
34
Q

Why are protocols necessary?

A
  • They ensure interoperability* Provide facility for error detection and correction* Ensure security* Allow efficient communication
35
Q

Why can the speed of data transmission vary?

A
  • Type of connection* Time of delay* Distance* ISP* Cable quality*