Network architecture practice questions.

A design studio has six computers, no machine that stays switched on overnight and no technician. Project files have to be shared directly between the machines. Which network architecture suits this situation best?

• Peer-to-peer, with each machine sharing its own files with the others
• Client-server, with one dedicated machine holding all the shared files
• Thin-client, with all of the application processing carried out centrally
• Cloud hosting, with every file uploaded to an external provider first

Answer: Peer-to-peer, with each machine sharing its own files with the others

Peer-to-peer needs no always-on machine and no specialist administration, which fits a small office; each computer both offers and requests resources. A client-server design would demand a dedicated machine that is exactly what this studio does not have.

A laptop joins a school network and receives an IP address, a subnet mask and the address of the gateway without anyone typing anything in. Which server has supplied them?

• The proxy server, which passes the laptop's requests out to the internet
• The file server, which stores the settings of every account on the network
• The mail server, which registers the laptop so that it can receive messages
• The DHCP server, which allocates addresses from a pool for a fixed period

Answer: The DHCP server, which allocates addresses from a pool for a fixed period

DHCP hands out addresses automatically from a pool and leases them for a limited time, which is what lets a visiting device work with no configuration. A DNS server answers a different question: it turns a name into an address the device already knows how to reach.

Why does replacing a hub with a switch usually reduce the number of collisions on a wired LAN?

• A switch repeats every frame it receives to all of its other ports
• A switch raises the rated bandwidth of each cable attached to it
• A switch forwards a frame only to the port of its destination
• A switch stores every frame permanently so that it can be resent later

Answer: A switch forwards a frame only to the port of its destination

A switch learns which address sits on which port and sends each frame down that port alone, so two conversations between different pairs of devices no longer compete for the same wire. A hub repeats everything everywhere, which is precisely why collisions occur.

Which task is carried out by a router, but not by a switch or a wireless access point?

• Passing data between two separate networks that use different address ranges
• Sending a frame to one attached device instead of to all of them
• Encrypting the radio traffic between a laptop and the point it is associated with
• Providing extra sockets so that more devices can join the same network

Answer: Passing data between two separate networks that use different address ranges

A switch moves frames between the ports of one network and an access point only bridges radio devices onto that same network, whereas a router joins networks and decides where a packet goes next. Calling a router 'a switch with more ports' loses that distinction entirely.

Why is a full mesh topology rarely chosen for a large office network?

• A single break in the shared backbone stops the entire network
• The number of cables and ports rises steeply as nodes are added
• Every message has to pass through one central device to be delivered
• Only one device may transmit at any given moment on the network

Answer: The number of cables and ports rises steeply as nodes are added

A full mesh of n nodes needs n(n-1)/2 links, so 20 machines would already require 190 cables and 19 ports each. The other options name faults of other layouts: one break stopping everything is a bus, delivery through one central device is a star, and only one node transmitting at a time is any shared-medium or token-passing arrangement, that is a bus or a ring.

A start-up runs its customer application on rented cloud infrastructure instead of buying machines of its own. Which is the clearest advantage of that decision?

• Data no longer needs to be backed up because it is stored remotely
• The application will continue to run when the internet link is lost
• Legal responsibility for the customers' personal data passes to the provider
• Capacity can be increased or reduced as demand changes

Answer: Capacity can be increased or reduced as demand changes

Elasticity is the property that a rented platform genuinely adds: the firm pays for the capacity it uses instead of sizing hardware for its busiest hour. Backup duties and legal responsibility for personal data stay with the organisation that collected it.