Cambridge A Level Information Technology (from 2017) 9626 — 2025 Oct/Nov Paper 3 · Variant 3

1 Cellular networks provide mobile communication systems. Describe the structure of a cellular network. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [4]

Mark scheme: Question Answer Marks 1 Four from: 4 • Base station connected to public telecommunications network / service provider that connects to public telecoms (1st) – Has antenna / receiver / transmitter (1) • Uses low power / short range • Radio / signals / wireless communications • (Each base station) has range of / 10–50 frequencies allocated • Different set of frequencies to adjacent base stations • Base station serves / covers small geographical area / terrain landscape • Base station uses towers (to increase height of antennae) • Many base stations used to cover large areas / cities • Handoff system to allow seamless movement from one base station to next (as users connect / disconnect from base stations as they move from place to place)

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2 A work flow shows how a task is carried out and completed in a project. (a) Describe two elements that should be included in a project work flow. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2] Project managers can use project management software to create and use work flows during a project. (b) Describe how work flow is used by a project manager. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4]

Mark scheme: 2(a) Two from: 2 • The steps needed to complete a task / activity • The resources needed for each step • The team members / workers needed for each step • How the team members / worker interact with each other • Indication of order of tasks / jobs 2(b) Four from: 4 • Used to show critical path within a project • Used to decide / shows the order of tasks • Shows where resources should be allocated • Shows where / how / which staff / workers should be allocated • Shows when resources should be allocated / made available • Used to calculate the cost of each activity / task • Used to automatically send orders for resources • Used to generate alerts / reminders (used to link to calendar / diary of managers / team members / workers)

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3 Discuss the impact of the Internet of Things (IoT) on the environment. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [8]

Mark scheme: 3 Eight from: 8 Command word: Discuss – write about issues(s) or topic(s) in a structured way. Content areas could include e.g.: • Global warming due to e.g. CO2 production • Use of smart energy meters to monitor energy use • Raise awareness of energy use / reduce energy use / reduce CO 2 production • Connecting cars / vehicles to the internet navigation services / directing them onto optimal routes • Saves car driving time fuel so less CO2 production • Protection of wildlife / monitoring species endangerment / protection using IoT devices to track wildlife / biodiversity • Devices fixed to trees / animals to monitor wildlife activities • Remote monitoring / listening devices / cameras of conservation areas to prevent e.g. hunting / poaching • Valid example e.g. monitoring inside beehives to protect bee colonies, bees responsible for pollination / food production • Listening devices on trees to monitor (illegal) logging • Automatic management / preservation of resources e.g. heat / water / light / waste • (IoT connected devices) allow more precise control over deployment / use / removal / conservation than possible by humans • Valid example e.g.: automatic re-ordering of goods by refrigerators / remote control of heating / climate control systems / ordering of e.g. fertilisers / animals by farmers / automatic milking systems / water leak sensors • Reduction in waste of resources • Increased food security • E-waste increase due to more devices • Increase in communication traffic • IoT devices are always ‘on’ / active • Increase in use of electrical power • Smart homes use more electrical power • Technology uses more energy so increased CO2 production • Heat output from devices • Increase in production of heat • Increase in battery use / more batteries produced / discarded • Add to landfill / disposal requirements / recycling

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4 Pivot tables are used to analyse data. (a) Describe a data source that could be analysed using pivot tables. ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [1] (b) Describe the benefits of using pivot tables to analyse data. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4]

Mark scheme: 4(a) One from: 1 • Database (table) / spreadsheet (workbook / sheet) containing related data in a file // related data in a file / database / table / spreadsheet / workbook / sheet 4(b) Four from: 4 • Manageable / same time / all in one go / simultaneous analysis of large quantities of data • Interactive analysis of data / can ‘see’ into / have insights into large amounts of data • Can generate multiple reports from single / same data set • Simple / easy / little training / specialist knowledge needed to carry out the analysis • Rapid discovery of patterns in complex data • Can work with external files / SQL generated exports of data in reports.

5 Message switching can be used in networks to transfer data between devices. (a) Describe how message switching transfers data between devices. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [3] (b) Explain why message switching is used to transfer data. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4]

Mark scheme: 5(a) Three from: 3 • Complete message is sent / transferred at once / in one go • Message contains destination address • Address used to send message to destination / route the message to next node • Store and forward method of transmission used (by intermediate nodes / router / switch / email servers) 5(b) Four from: 4 • Makes efficient use of available bandwidth because connections / data links / channels are shared between devices • If network fails / congestion message is not lost because messages are stored at message switches / intermediate nodes / mail servers • Networks / devices can be configured to prioritise messages so that important messages arrive first • Messages can be broadcast to several destinations at once to avoid repeating the message • Storage of message by node so message is not lost / retries of sending are possible.

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6 A supermarket uses Wi-Fi instead of copper cables in its stores to connect sales terminals into its network. Discuss the advantages and disadvantages of using Wi-Fi for the connections. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [8]

Mark scheme: 6 Eight from: 8 Command word: Discuss – write about issues(s) or topic(s) in a structured way. Max six from: Advantages: • No wires to cause physical / electrical hazards for customers / staff • Can be used where physical wiring is not possible / too expensive / not allowed • No installation / maintenance of physical wiring / infrastructure so costs are reduced • Cleaning / servicing (of checkout areas) is more convenient without network wiring • Checkouts / point of sale terminals can be added / removed without disrupting network connections • Checkouts / point of sale terminals can be moved / relocated without the need to alter network wiring • No need to damage / alter e.g. walls / displays / floors / infrastructure • No cables to get damaged Max six from: Disadvantages: • Requires complex / more network security / enforced security than wired connections • Range is limited / affected by obstacles / materials / goods / construction materials in store • More WAPS may be needed to cover the area / network becomes more complex • Range may restrict the placement of checkouts / point of sale terminals • More susceptible to unauthorised access / eavesdropping / cyber attacks • Range may extend beyond store perimeter so more difficult to keep secure • Susceptible to interference from other / staff / customer Wi-Fi devices • From electrical devices in the store / valid example e.g.: food freezers / TV sets.

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7 The JavaScript code in Fig. 7.1 is executed when it is loaded into a web browser. The line numbers are for reference only. 1 <html> 2 <body> 3 4 <p id="ALP3"></p> 5 6 <script> 7 8 const qp = ["A Level", "IT", "9626", "Paper", 3]; 9 10 let paper = ""; 11 for (let x in qp) { 12 paper += qp[x] + "<BR>"; 13 } 14 15 document.getElementById("ALP3").innerHTML = paper; 16 17 </script> 18 19 </body> 20 </html> Fig. 7.1 Explain how the code produces the list shown in Fig.7.2. File | M:/CIE/202... A Level IT 9626 Paper 3 Fig. 7.2 .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [6]

Mark scheme: 7 Six from: 6 • JS code embedded within HTML − inside < / script> tags • ALP3 is given id in line 4 • Array qp holds the text for display / ["A Level", "IT", "9626", "Paper", 3] • Variable paper declared / initialised to empty / blank / null / zero • for in used to loop / iterate through array • Variable x used to count / hold array items during loop iterations • Variable paper used to construct / hold array item plus line break − BR used to force line break on web page • Contents of variable paper written / passed back to HTML… using document.getElementById("ALP3").innerHTML = paper − HTML element with id ALP3 − initiated before script as blank − JS changes its content to contents of variable paper − displayed on web page • Iterates through array until no more items left − JS script / code terminates / stops

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8 In computer animation, objects can be made to appear to move at different speeds. Describe how an animator can control the speed at which objects appear to move. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [6]

Mark scheme: 8 Six from: 6 • Use of timeline − to decide when movement occurs − how fast movement occurs / how fast change of position occurs • Spacing / position of object within a frame − change from frame to frame − smaller spacing appears as slower movement − larger spacing appears as faster movement • Number of frames used to complete the movement − many frames appear as slow movement − few frames appear as fast movement − animating on ones / twos / threes − on 1s means fast action − on 2s means ‘normal’ movement − on 3s means slow movement • Use ‘slow in slow out’ approach − first / last few frames / spacing of movement less than middle set of frames − more realistic start / stop of movement

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9 Central bank digital base money is a type of digital currency. Describe the characteristics of central bank digital base money. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [4]

Mark scheme: 9 Four from: 4 • A digital representation of sovereign / country’s currency • Issued by a central bank / central monetary authority − which guarantees / backs / supports the CBDC − considered to be legal tender • Value set against the flat currency / usual currency • Easily transferred using peer-to-peer networking

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10 (a) Describe how BitTorrent is used to transfer large files. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [4] (b) (i) Explain why network administrators may decide to restrict the use of BitTorrent. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [3] (ii) Describe one way that a company employee may still be able to use BitTorrent despite the restrictions put in place by network administrators. ........................................................................................................................................... ........................................................................................................................................... ..................................................................................................................................... [1]

Mark scheme: 10(a) Four from: 4 • BitTorrent client installed / used on device • Uses BitTorrent protocol to connect to other clients / devices • It is a peer-to-peer network of connected devices / devices connected into BitTorrent ‘swarm’ • Data / files are transferred between devices directly / without a central server • Connected devices use a distributed hash table (DHT) to track other clients / are tracked by others / use of a .torrent file by BitTorrent client / by tracker device • Connected devices have the IP addresses shared with all other connected devices • Tracker device does not contribute / store / send any data files • Clients search for files / files located on other clients using the DHT • Files are downloaded in bits / parts / sections • (downloaded) from multiple clients / different clients • Files are reconstructed by the client • Clients supplying files share their bandwidth to reduce time for file download to client • Clients with complete / fully downloaded files share with other clients 10(b)(i) Three from: 3 • BitTorrent protocols use a large amount of the available bandwidth which increases network traffic / slows network down • Many users all attempting to find / access / download files using BitTorrent so it makes it appear that a DDoS attack is underway • BitTorrent is based on UDP so source addresses can be ‘spoofed’ / changed / disguised • BitTorrent files can carry malware (which is distributed to all users) • It can be used to distribute / download copyright / illegal materials so can cause legal problems for the network owners • Contravenes company acceptable use policy so may be a training / disciplinary issue // not using company network for work purposes 10(b)(ii) One from: 1 • Set up a VPN • Disguise / encrypt the BitTorrent protocol as another protocol / use Message stream encryption / Protocol encryption (MSE / PE) to avoid its detection

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11 A new stock control system is to be installed at a supermarket warehouse. Different methods of implementing the changeover from the old system to the new system are being considered by the management of the supermarket. Discuss the benefits and drawbacks of direct changeover. .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .................................................................................................................................................... [8]

Mark scheme: 11 Eight from: 8 Command word: Discuss – write about issues(s) or topic(s) in a structured way. Max one from: • The old system is stopped and the new system starts / is used immediately / overnight Max six from: Benefits: • The benefits of the new system can be had immediately after installation / implementation − no delays / loss of work / production / service / deliveries / shipments • Fastest method of installation / implementation compared to other methods − reduced loss of profit and no loss of customers • Only one system is running at any one time − no need to have two sets of hardware / staff − reduced costs of staffing • New system is less likely to have issues / problems / bugs − as has been fully tested before deployment Max six from: Drawbacks: • Staff have to be trained before the new system is installed − staff have to be trained instead of doing real / proper job − reduced productivity by work force during training − staff cannot be trained on a live system − staff have to be trained on a simulated / training system − staff can make mistakes on a training system so get a false sense of security • Old system data has to be transferred to new system − increased risk of data loss − can be time-consuming so may introduce delays − no fallback option if new system fails − stock data may be permanently lost − deliveries / shipments / business may stop / fail • No system at all / may not be available during the point of changeover − old system is not available if the new system fails − so business may not be available to operate

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