networks

Question 1

packet-switched network

Answer 1

• no dedicated route for transmission
• data to be sent is broken up into packets (packets may arrive out of order)
• each packet may go by a different route to its destination

Question 2

circuit-switched network

Answer 2

• transmission route dedicated before transmission
• data sent in continuous stream (packets arrive in order)

Question 3

problems of circuit-switched that is addressed by packet-switched (char of packet)

Answer 3

• only sender needs to be ready before transmission begins
• if any segment of the network is disrupted, data packets can be routed around the disruption through other segments of the network
• if part of data is lost/corrupted, only these data need to be retransmitted
• congestion segments can be bypassed if other segments are available, enabling greater utilisation of the network

Question 4

disadvantages of packet-switched network + how solve

Answer 4

• packets may arrive in different sequeunce :. sequence number/info can be added to packet headers, enabling reassembly of payload
• retransmission can cause data corruption :. error-checking code can be added in packet header, enabling checking of integrity of data

Question 5

client def

Answer 5

program/device used by end-user that sends request to server

Question 6

why is client-server model useful?

Answer 6

• centralisation of data / data easier to control
• easier to ensure security of data bc only server needs to be secure :. more convenient to upgrade/control/manage main server than peer-to-peer model

Question 7

cloud server idea def

Answer 7

acts as someone else’s computer that you dont own

Question 8

advantages & disadvantages of cloud server

Answer 8

advantages
- lower operating costs bc dh hardware maintenance
- simpler management / less staff trng req

disadvantages
- less control over data :. greater difficulty in meeting pdpa obligations
- difficult to investigate if cloud provider hv properly implemented security measures

Question 9

local area network (LAN)

Answer 9

devices connected within a small geographical area, typically within a room / building

Question 10

wide area network (WAN)

Answer 10

network of computing devices covering large-scale geographical area, typically across multiple geographical locations

Question 11

why not circuit?

Answer 11

• no time-sensitive data (audio/video streaming) to be transmitted
• insufficient network resources to dedicate a transmission path