U2 communications Flashcards
What does a router do?
- 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
What does a switch do?
Connected to all devices in a LAN and simultaneously transfers data to all devices
What does a server do?
Device/software that provides specific function for computers in a network
What does an NIC(Network interface card) do?
Gives each device in a wired LAN a unique MAC address to identify it
What does a WNIC(Wireless network interface card) do?
- 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
What does a wireless access point(WAP) do?
- Hardware that provides radio communication from central device to nodes in a network
What do cables do?
Wired transmission medium that allows communication in a medium
What do bridges do?
- 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
What does a repeater do?
- Connects two cables
- Regenerates the signal sent over the same network before the signal weakens to prevent corruption
What does a modem do?
- 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
What does a PSTN(Public Switched telephone network) do?
- 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
What do dedicated lines do?
- 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
What does a cellphone network do?
- 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
Ethernet
Protocol suite for data transmission over a standard wired network connection. Uses CSMA and collision detection.
Thick client model
- The server performs minimal processing for the client
- The clients also do most of their own processing independently
