Networking and Web Technologies

Question 1

DNS

Answer 1

1. Request sent to DNS resolver (finds IP address corresponding to URL)
2. Resolver checks it’s cache and if it doesn’t find the IP address, it passes it onto TLD name server
3. IP address is sent back to the client
4. If not found, an error is sent back

Question 2

Circuit switching

Answer 2

• Direct link between two devices for the duration of the communication e.g. phone calls
• no delay in receiving and sending data, and data packets arrive already in order
• bandwidth is wasted when no data is being transmitted

Question 3

Packet switching

Answer 3

• data is broken down into more manageable chunks
• packet contains header (IP addresses of sender and recipient, packet number)
• payload (actual data being transmitted)
• and trailer (checksum - error checking data)

Question 4

TCP/IP stack

Answer 4

• packets encapsulated in new packet data
• application - application being used to transmit
• transport - data split into packets, header of order put packets and trailer of port added
• internet - IP address of sender and recipient added
• link - MAC address of recipient added, so can find computer once teaching network

Question 5

Client-server networking

Answer 5

• Client computers connected to a powerful central computer (server)
• better security, centralised management (backups, software)
• expensive to set up and manage

Question 6

Peer to peer networking

Answer 6

• computers are connected to each other (have equal status) and share data
• cheap, not difficult to maintain
• used in online piracy