Computer networks worksheet with answers

Which type of network covers a large geographic area, such as a whole country?

1. AA personal area network (PAN)
2. BA wide area network (WAN)
3. CA local area network (LAN)
4. DA virtual LAN (VLAN)

In the client-server model:

1. AServers send requests and clients answer them
2. BClients send requests and a server provides the service
3. CEvery computer stores the whole internet
4. DAll devices must be in the same room

What is the main job of a firewall?

1. ATo speed up downloads by caching files
2. BTo allow or block traffic according to security rules
3. CTo assign IP addresses to hosts
4. DTo convert domain names into addresses

What does ARP do?

1. ARoutes packets on the internet
2. BAssigns IP addresses automatically to hosts when they join the local network
3. CFinds the MAC address that belongs to an IP address on the local network
4. DResolves domain names

How long does it take to put a 1500-byte packet onto a 12 Mbit/s link (transmission delay)?

1. A1 ms
2. B8 ms
3. C0.125 ms
4. D12 ms

What is the purpose of the TCP three-way handshake?

1. ATo close a connection quickly
2. BTo encrypt the data
3. CTo establish a connection and synchronise sequence numbers
4. DTo find the IP address of a host before data can be sent to it

Why does TCP choose an unpredictable initial sequence number for each connection?

1. ATo compress the data more efficiently
2. BTo encrypt the payload of each segment
3. CTo select the best route to the destination for the segments of that connection
4. DTo avoid confusion with old segments and make spoofed segments harder to inject

Why was the TCP window scale option introduced?

1. AThe 32-bit window field was too large and wasted header space in every TCP segment sent
2. BThe 16-bit window field limits the window to 65,535 bytes, too small for fast long-distance paths
3. CUDP needed a way to control its sending rate on congested paths
4. DWithout it, TCP could not detect lost segments on long-distance links