Networks and the Internet: practice questions

Question 1

Which statement correctly distinguishes the internet from the World Wide Web?

Accepted Answer

B

Question 2

BrightDesk Architects has 12 computers in one open-plan office, all within a single building. The office's IT technician, Priya, is choosing how to cable the computers together to form a local network, and is comparing three cabling arrangements: a bus topology, a star topology…

Accepted Answer

((a)) LAN. All 12 computers are in one office within a single building (one site), whereas a WAN connects devices or networks across multiple, geographically separated sites.  ((b)) Advantage: if one cable or computer fails, only that one computer loses its connection, since the rest still connect independently to the switch, unlike a bus where a single break in the shared backbone cable disables the whole network. Disadvantage: a star needs far more cable…  ((c)) Advantage: much greater fault tolerance, since every computer has an independent direct link to every other computer, so there is no single point of failure (not even a central switch), and one failed cable does not affect any other connection. Reason it is impractical: the numb…

Question 3

A household has a router that connects several devices - a laptop, a smart TV and a phone - to the internet through their internet service provider (ISP). (a) State one structural difference between an IPv4 address and an IPv6 address. [2] (b) The router assigns each of the thre…

Accepted Answer

((a)) An IPv4 address is 32 bits long, usually written as four decimal numbers (each in the range 0 to 255) separated by dots, e.g. 192.168.1.1. An IPv6 address is 128 bits long, usually written as eight groups of four hexadecimal digits separated by colons, e.g. 2001:0db8:0000:0000:0…  ((b)) A public IP address is globally unique across the whole internet and can be reached directly by any other device on the internet; a private IP address is only unique within its own local network and is never routed across the public internet. Because private addresses are never…  ((c)) One way: a MAC address is a fixed, physical address built into the NIC by its manufacturer and never changes, even if the laptop joins a different network, whereas an IP address is a logical address assigned by the network (here, by the router) and can change - for example, if t…

Question 4

GreenLeaf Dental Clinic runs a small office network. Patient appointment records are centrally stored and updated only on a dedicated file server kept in the back office; no other computer on the network keeps its own copy of this data. The receptionist's computer displays a pat…

Accepted Answer

((a)) Client-server model. The client is the receptionist's computer, since it is the device requesting the patient's appointment record; the server is the back-office file server, since it is the device that stores and centrally provides the record on request.  ((b)) The requesting device sends a request to a DNS server, asking for the IP address that matches the domain name portal.greenleafdental.example.com. The DNS server looks up this domain name in its own records (querying further DNS servers if it does not hold a matching record itsel…  ((c)) The router directs (routes) data between the clinic's own network and external networks, such as the ISP and the wider internet; the switch only forwards data between devices that are already on the same local network (such as between the reception computer and the file server)…  ((d)) Advantage: a wired Ethernet connection to the switch is generally more reliable and offers higher, more consistent bandwidth than a wireless connection, since it is not affected by interference from walls, distance from the wireless access point, or other wireless devices compet…

Question 5

A small company is comparing two possible network connections for its new office before signing a contract with an internet service provider.

Which statement correctly describes what is meant by the bandwidth of a network connection?

Accepted Answer

B

Question 6

Meridian Bookkeeping currently saves every client file on the hard disk inside each accountant's own desktop computer. The office manager is considering switching to a cloud storage service instead, so that files are kept on servers run by an external provider and reached over the internet.

Which statement correctly describes what is meant by cloud computing?

Accepted Answer

B

Question 7

Skyline Design Collective has three freelance designers, each working on their own laptop. They share large image files directly between their laptops using peer-to-peer file-sharing software installed on every machine: any laptop can send a file straight to, or receive a file s…

Accepted Answer

((a)) Peer-to-peer model. Every laptop can act as both a sender and a receiver of files directly to and from the other laptops, and there is no dedicated central computer that stores the master copies - this is the feature that identifies it as peer-to-peer rather than client-server.  ((b)) Advantage: no dedicated server needs to be bought, set up or maintained, so the arrangement is cheaper and simpler for just three designers, and there is no single central machine whose failure would stop every exchange of files. Disadvantage: because every laptop can hold and e…  ((c)) Yes. Switching to the client-server model would help, because a dedicated server would hold the single, authoritative copy of each design file that every designer's computer (now a client) requests and updates, removing the risk of conflicting versions spread across separate lap…

Question 8

Harborview Logistics has been allocated the IPv4 address block 192.168.20.0 with the default subnet mask 255.255.255.0 (a /24 network) for its head office. The network manager needs to split this single block into 4 separate subnets, one each for the Sales, Accounts, IT and Ware…

Accepted Answer

((a)) 8 host bits (the whole last octet, since mask 255.255.255.0 makes the first three octets network bits and leaves the last octet, 8 bits, as the host portion). The default /24 mask cannot create 4 subnets on its own because it defines only one single network with one continuous r…  ((b)) 2 bits are borrowed (192 in binary is 11000000, so 2 of the last octet's bits become extra network bits instead of host bits). Borrowing 2 bits produces 2 squared, which is 4, separate subnets - matching the 4 departments that each need their own subnet.  ((c)) 6 host bits remain in each /26 subnet (the 8 original host bits minus the 2 borrowed for subnetting), giving 2 to the power 6, which is 64, addresses in each subnet. Of these, 2 addresses (the subnet's own network address and its broadcast address) cannot be assigned to hosts, l…

Question 9

Oakwood Community Centre's older classroom LAN connects six computers to a hub. The hub simply repeats every signal it receives out to all of its other ports, so all six computers share the same transmission medium, and only one signal can be present on that medium at any instan…

Accepted Answer

((a)) Carrier Sense Multiple Access with Collision Detection.  ((b)) The computer first listens to (senses) the shared medium to check whether another computer is already transmitting a signal on it. If the medium is sensed as free, the computer begins transmitting its data, and continues to monitor the medium while it transmits. If two computers…  ((c)) If both computers retransmitted immediately after the collision, they would very likely sense the medium as free again at the same instant and collide a second time. Choosing an independent, random amount of time to wait before retransmitting makes it much less likely that both…

Question 10

Solstice Bakery's website can be reached using the URL https://www.solsticebakery.example.com/menu/pastries.html.

Which statement correctly identifies the protocol, the domain name and the path used in this URL?

Accepted Answer

B

Networks and the Internet: Computer Science 9618 (Cambridge International AS & A Level)

Syllabus coverage

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10