Unit 5 - Networks

Question 1

What is packet switching?

Answer 1

• a method of data transmission
• messages are broken into chunks called packets
• each packet is sent independently over the optimal route
• and reassembled at its destination

Question 2

What is circuit switching?

Answer 2

• Creating a direct link between two devices on a network for the duration of their communication

Question 3

What are the disadvantages of circuit switching?

Answer 3

• Bandwidth is wasted during the periods when no data is being sent
• Both devices must transfer and receive data at the same rate
• (advantage) data packets arrive in the order they are sent because there is only one path connecting the devices

Question 4

What is the difference between a router and a switch?

Answer 4

• Routers forward data packets from one network to another; switches forward data packets within a LAN

Question 5

What is the difference between a bridge and a gateway?

Answer 5

• Bridges transfer data packets to LANs which use the same protocols; gateways transfer data packets to networks which use different protocols

Question 6

What is the difference between a MAC and IP address? (4)

Answer 6

• MAC addresses are globally unique; IPs are unique within their network
• MAC addresses are a physical address; IPs are a logical address
• MAC addresses operate in the data link layer; IPs operate in the network layer
• MAC addresses cannot change; IP addresses can change by connecting to a new network.
• MAC addresses made of 6 2-digit hexadecimal number separated by colons; IPs are made of four 8-bit values separated by full stops.

Question 7

What is the TCP/IP process? (4)

Answer 7

• TCP splits data into data packets
• which are sent to recipients and reassembled into their original order
• TCP checks the data is correctly sent and delivered
• IP directs packets to their destination across the network

Question 8

What is packet filtering?

Answer 8

• The firewall checks which ports data packets are trying to access and allows them through if they are using the correct port

Question 9

What is packet sniffing?

Answer 9

• Data packets flowing across a network are detected and observed

Question 10

What is a network? (2)

Answer 10

• Two or more computers connected…
• …To share resources

Question 11

What is the World Wide Web? (1)

Answer 11

• A collection of resources accessed via the internet

Question 12

Describe the structure of the Internet. (2)

Answer 12

• The Internet is connected using large international backbone cables
• Which pass underwater to connect continents.

Question 13

What is IPv6? (2)

Answer 13

• IPv6 is a new Internet Protocol addressing system which consists of 8 groups of 4 hexadecimal digits.
• This allows for more unique addresses than IPv4.

Question 14

Describe the structure of a data packet. (3)

Answer 14

• Header: contains sender/recipient IP, protocol, and packet number.
• Payload: contains 500 to 1500 bytes of data.
• Trailer: End of packet flag, checksum