U2 communications

Question 1

What does a router do?

Answer 1

• Connects two networks together which may operate on different protocols
• Allows internal connections in a LAN
• Allows external connections between LAN and WAN
• Acts as gateway and firewall
• Translates public IP address to private and vice versa

Question 2

What does a switch do?

Answer 2

Connected to all devices in a LAN and simultaneously transfers data to all devices

Question 3

What does a server do?

Answer 3

Device/software that provides specific function for computers in a network

Question 4

What does an NIC(Network interface card) do?

Answer 4

Gives each device in a wired LAN a unique MAC address to identify it

Question 5

What does a WNIC(Wireless network interface card) do?

Answer 5

• Provides interface to wirelessly connect to the network as an antenna
• Receives analogue radio waves, converts to digital/binary
• Checks incoming transmissions for MAC address
• Encodes and Decodes data

Question 6

What does a wireless access point(WAP) do?

Answer 6

• Hardware that provides radio communication from central device to nodes in a network

Question 7

What do cables do?

Answer 7

Wired transmission medium that allows communication in a medium

Question 8

What do bridges do?

Answer 8

• Connect two LANs which work with the same protocol, could be two segments of the same network
• stores network address for all devices between two networks
• Bridge looks for receiving device before it sends the message

Question 9

What does a repeater do?

Answer 9

• Connects two cables
• Regenerates the signal sent over the same network before the signal weakens to prevent corruption

Question 10

What does a modem do?

Answer 10

• Allows device to connect to internet with phone line
• Transmitter uses modem to convert digital signals to analogue that are sent down the telephone line
• Receiver uses modem to convert analogue signals to digital ones so device can process data

Question 11

What does a PSTN(Public Switched telephone network) do?

Answer 11

• Refers to all telephone networks
• Channel used between 2 end-points for call duration via circuit switching
• Lines active during power outage
• Bi-directional communication

Question 12

What do dedicated lines do?

Answer 12

• Telecommunication path between endpoints
• Not shared between multiple users
• Able to host phone websites and carry phone calls
• Allows continuous, uninterrupted access to the web

Question 13

What does a cellphone network do?

Answer 13

• wireless network spread over land areas divided into cells
• each cell served by at least one base station which uses a different frequency range to transmit data
• large capacity possible since same frequency can be used in non-adjacent cells
• radio waves usually used for transmission
• can be broadcast in all directions
• portable receivers (e.g. mobile phones) able to communicate and access internet via base station

Question 14

Ethernet

Answer 14

Protocol suite for data transmission over a standard wired network connection. Uses CSMA and collision detection.

Question 15

Thick client model

Answer 15

• The server performs minimal processing for the client
• The clients also do most of their own processing independently