Communication & Networking Flashcards
Describe how parallel transmission works (2 marks)
Bits are sent simultaneously across multiple/different wires
State the purpose of the start but in asynchronous transmission (1 mark)
Start the receiver clock ticking // to synchronise the recover and transmitter clocks
State the purpose of the stop bit in asynchronous serial transmission (1 mark)
Allows the next start bit to be recognised // provides time for the receiver to process/transfer the received data
Advantages of serial transmission over parallel transmission (1 mark per advantage)
- does not have risk of crosstalk
- does not have risk of data skew
- can be used over long distances
- hardware/wiring for serial is cheaper
Define latency (1 mark)
The time delay that occurs when transmitting bits between 2 devices.
Compare how peer to peer networking and client -server networking work (3 marks)
- client server will have one or more Central servers and the rest of the nodes will be clients that connect to the servers
- a peer to peer network will not have a centralised security management system
- peer to peer networks allow nodes to share resources between each other
(Many more can be said, these are just a few)
Explain why a peer to peer network would be most appropriate to use in the house (3 marks)
- small number of users/clients
- users can choose what they want to share
- they can avoid the cost of buying a server
Describe the main purpose or the DNS system and how it works (3 marks)
A DNS stores domain names (better word -FQDNs) and maps them to their IP address.
A device will send a request for a domain name and this domain name will be searched for in the DNS table.
If it is not found, the domain name will be searched for in a different domain name server.
What is bluetooth (2 marks)
wireless technology for exchanging data over short distances
Why are devices connected to a LAN usually given non-routable IP addresses? (2 marks)
there may not be enough unique IP addresses for each device to have a routable IP address. It can also be for added security as devices outside the network will not be able to connect to devices inside the network.
How is subnet masking carried out? (3 marks)
the AND operation is performed on the IP address of the transmitting device and its subnet mask. The same is done to the IP of the receiving device and it’s subnet mask. If the 2 outputs are the same, the 2 devices are on the same network however if they are not, they are on different networks.
How might a firewall control the data that flow between the LAN and the Internet? (3 marks)
- Blocks traffic on specific ports
- Searches packets for specific content
- identifies unusual behaviour from the host such as unusually large data transfers
(one BP per mark)
could also have - stateful inspection (and what it does)
NOT ENOUGH TO JUST SAY PACKET FILTERING.
Explain the difference between broadband and baseband connection (1 mark)
baseband is when the bandwith of a medium is dedicated to one transmission only; broadband is when the bandwidth of a medium is shared to multiple wires.
Explain why bus toplogies are often segmented (2 marks)
to reduce the number of collissions and to reduce the network congestion. This can be done by reducing the number of stations at one section of the cabling.
what are 2 differences between LAN and WAN apart from the fact that LAN covers smaller area than WAN (2 marks)
LAN uses baseband and WAN uses broadband; LAN has lower latency; LAN is less prone to errors comapred to WAN transmissions.
Explain what a server opating system is (1 mark)
an OS optimised to provide services to clients on the network
what is meant by packet switching? (2m)
when messages are split into packets and each packet is given a destination /source address.
(NOTE: can have many more answers but these make most sense to me)
