2.1 Networks including the Internet
AS Level · 27 questions found
What this topic covers
Section titled “What this topic covers”- LAN vs WAN characteristics; purpose/benefits of networking devices
- Client-server vs peer-to-peer; thin-client vs thick-client
- Topologies: bus, star, mesh, hybrid — packet transmission and justification
- Cloud computing: public/private clouds, benefits and drawbacks
- Wired vs wireless: copper, fibre-optic, WiFi, microwave, satellite
- LAN hardware: switch, server, NIC, WNIC, WAP, bridge, repeater
- Router function; Ethernet; CSMA/CD collision detection/avoidance
- Bit streaming: real-time vs on-demand; broadband speed impact
- WWW vs internet; internet hardware: modem, PSTN, dedicated lines, cell phone network
- IP addresses: IPv4/IPv6, subnetting, public/private, static/dynamic
- URL, DNS and locating web resources
Past paper questions
Section titled “Past paper questions”Web browsers use Internet Protocol (IP) addresses.
(a) Complete the table by describing the following types of IP address.
| Type of IP address | Description |
|---|---|
| Static | |
| Public |
(b) Consider the following IP address:
256.0.0.A Circle whether this IP address is IPv4, IPv6 or an invalid IP address. 2 marks
IPv4 IPv6 Invalid Justify your choice. 2 marks
(c) A user types a Uniform Resource Locator (URL) into the address bar of a web browser to access a web page. 4 marks
Explain how the web browser uses the URL to access the web page.
(d) A bitmap file is downloaded. The image has a maximum of 256 colours and measures 512 pixels wide by 2048 pixels high.
(i) Calculate an estimate of the file size of the bitmap in kibibytes. 2 marks
Show your working.
Working
File size of bitmap ______ kibibytes
(ii) Explain why the actual file size may be larger than the one calculated in (d)(i). 2 marks
(iii) Explain how a bitmap image is compressed using run-length encoding (RLE). 2 marks
Show mark scheme
7(a) [2 marks]
1 mark for each correct description, max 2 marks Type of IP Description address IP address that does not change each time a device Static connects to the network IP address assigned to a device on a network to allow the Public device to be visible on the internet
7(b) [2 marks]
1 mark per bullet point for justification, max 2 marks Choice: Invalid (no mark for the choice) Justification: • It is not IPv4 because the maximum denary value should be 255, this uses 256 • It is not IPv6 because it uses a full stop to separate sections and not colon // It is not IPv6 because there are not enough groups
7(c) [4 marks]
1 mark per bullet point, max 4 marks • The browser checks its cache for the URL • The browser parses the URL and splits it into its component parts • The browser finds the IP address for the domain name by querying a DNS server • The browser receives the matching IP address from the DNS server • The browser creates connection with the web server with the matching IP address • A request for the resource is sent to the web server with that IP address • The browser renders and displays the result • The IP address is stored in the browser cache for future use
7(d)(i) [2 marks]
1 mark for the working 1 mark for the correct answer Working: (512 * 2048 * 8) / (8 * 1024 ) // (512 * 2048) / 1024 // (2
- 2
- 2 ) / (2
- 2 ) // (2
- 2 ) / 2 9 11 3 3 10 9 11 10 Answer: 1024 kibibytes // 2 kibibytes 10
7(d)(ii) [2 marks]
1 mark per bullet point, max 2 marks • The file will contain metadata • The file will have a header
7(d)(iii) [2 marks]
1 mark per bullet point, max 2 marks • Sequences of consecutive identical colours / pixels • ... are stored as the colour value and the number of times it occurs consecutively
A local area network (LAN) has five computers, one switch and one server.
(a) Describe the characteristics of a LAN. 2 marks
(b) Complete the following diagram to show how these devices are connected in a star topology. 2 marks
Computer Computer
Computer Computer
Computer Server Switch
(c) Describe how packets are transmitted between two hosts using a star topology. 3 marks
(d) Another type of network is a bus network. 3 marks
Ethernet is used to transmit and receive data between the devices on the bus network.
Describe how collisions are detected and managed on this network.
(e) Complete the table by identifying one threat to computer and data security posed by networks and the internet. 3 marks
Describe the threat and give a method of prevention.
| Threat | Description | Prevention |
|---|---|---|
Show mark scheme
5(a) [2 marks]
1 mark per bullet point, max 2 marks • Covers a small geographical area • Normally privately owned / dedicated infrastructure • Can use wired or wireless communication
5(b) [2 marks]
1 mark per bullet point, max 2 marks • All computers directly connected to switch and no other connections • Switch connected directly to server
5(c) [3 marks]
1 mark per bullet point, max 3 marks • The sending device sends the packets to the switch • The switch checks the destination address on each packet • … and sends them only to the intended receiver
5(d) [3 marks]
1 mark per bullet point, max 3 marks • The use of CSMA/CD // Carrier Sense Multiple Access with Collision Detection • The workstations listen to the communication channel • ... and send data only when there is no data being transmitted / the line is idle • If a collision is detected, transmission is aborted • …and a jamming signal is sent • The workstation calculates a random wait time before trying to re-transmit • The random time is increased if there are multiple collisions
5(e) [3 marks]
1 mark for correct threat 1 mark corresponding description 1 mark for correct method of prevention Threat Description Prevention Malware / Malicious code that can Anti-virus // Anti- Virus alter/delete files malware // Firewall Spyware Records keystrokes which are Anti-spyware // sent to third party Firewall // Anti- malware Hacking Gaining unauthorised access to Authentication // a computer network / device Firewall Phishing Emails supposedly from Use a spam filter // reputable companies are sent to Do not open emails trick people into revealing from unknown personal information sources Pharming Users are directed to a bogus Use a VPN // Anti- website that looks legitimate to malware// Do not obtain personal information open links or download attachments
A restaurant accesses software and stores data using cloud computing.
(a) (i) Give two benefits of storing data using cloud computing. 2 marks
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(ii) Give two drawbacks of using cloud computing. 2 marks
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(b) The restaurant uses touchscreens as input devices to allow staff to select items from a menu.
(i) Explain how a touchscreen converts the point of touch to a selection from the menu. 4 marks
(ii) The image files that are displayed on the touchscreen have been corrupted. 2 marks
Identify two examples of utility software that could be used to recover the images.
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2
Show mark scheme
8(a)(i) [2 marks]
1 mark per bullet point, max 2 marks • Cloud storage can be free of charge for a limited amount • There is no need for personal storage devices • The data can be accessed from any computer with an internet connection • Cloud data services usually include data backup and recovery services • It is easier to share data / collaborate with colleagues • Cloud storage capacity can be quickly and easily increased if needed
8(a)(ii) [2 marks]
1 mark per bullet point, max 2 marks • The storage/cloud can only be accessed with an internet connection • There may be no backups // possibly no control over backups // reliance on third party for backups • Uploading / downloading data could take a long time • Potential issues with the cloud storage company impacting access e.g. downtime or technical problems • Potential compatibility issues if wanting to move the data • Limited storage availability without paying extra • … meaning (possibly) more expensive in the long term • Possibly security issues
8(b)(i) [4 marks]
1 mark per bullet point, max 4 marks Methods to determine point of touch ( Max 2) • Resistive // two layers of material make contact and complete a circuit • Capacitive // contact with the screen creates a change in charge • Infrared // the beams are broken by the pointing device • Optical imaging // a shadow is created when the surface is touched • Acoustic pulse // the acoustic wave is absorbed by the pointing device • Selection from the menu ( Max 2 ) • The point of touch is used to determine the x and y coordinates • The menu item corresponding to the coordinate position is recognised and the menu item is added to the order
8(b)(ii) [2 marks]
1 mark per bullet point, max 2 marks • Disk repair / disk contents analysis • Back-up software
A network engineer is setting up a Local Area Network (LAN) in an office. The network uses both wired and wireless connectivity.
(a) Give three advantages of a wireless network compared to a wired network. 3 marks
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(b) Give one drawback of using a wireless network. 1 mark
(c) Complete the table by writing the name of the type of memory technology for each description. 3 marks
| Description | Memory technology |
|---|---|
| A read only memory where the contents can be erased using a voltage pulse. The contents can be changed multiple times without physically removing the memory. |
|
| A read only memory where the contents are erased using ultraviolet (UV) light. The memory must be physically removed to be reprogrammed. |
|
| A read only memory where the contents can be written only once after manufacture. |
Show mark scheme
4(a) [3 marks]
1 mark for each benefit, max 3 • Devices can be more mobile as no physical connection is required • No cabling is needed so easier to set up • Easier to add additional devices • Multiple different device types can be connected
4(b) [1 mark]
1 mark for a drawback • Can be less secure • Transmission speed can be slow • Interference is possible • The signal degrades quickly without repeaters/boosters
4(c) [3 marks]
One mark for each correct row Description Memory Technology A read only memory where the contents EEPROM can be erased using a voltage pulse. The contents can be changed multiple times without physically removing the memory. A read only memory where the contents EPROM are erased using ultraviolet (UV) light. The memory must be physically removed to be reprogrammed. A read only memory where the contents PROM can be written only once after manufacture.
Programmers in a software development company take part in live video conferences to discuss their work.
The live video conferences take place using real‑time bit streaming. The video is compressed before it is transmitted.
(a) Explain how data is transferred using real‑time bit streaming. 4 marks
(b) (i) Explain the reasons why a video is compressed before it is transmitted using real‑time bit streaming. 4 marks
Show mark scheme
2(a) [4 marks]
1 mark each to max 4 • Video is transmitted continuously • as a series of bits • The video is uploaded to a media server • The users download from the media server • On download, the media server sends the data to a buffer on the user's device • buffer is used when there is a difference in speed between transmission and receipt • Buffer stores data from server until recipient can receive it • Recipient views bit stream from the buffer
2(b)(i) [4 marks]
1 mark each to max 4 e.g. • Video is data-intensive • The file size needs reducing in order to • reduce the amount of bandwidth used • and reduce buffering • This means people are not behind in the conversation • and people with lower bandwidth can still take part
2(b)(ii) [3 marks]
No mark for choice but lossy is most appropriate 1 mark each to max 3 e.g. • Reduces file size more than lossless • so significantly less bandwidth / data is needed • so buffering is reduced even more than with lossless • Data can be removed which cannot be seen • reducing quality without impacting experience • for example, because resolution of video can be reduced // sample rate of audio can be reduced
2(c) [2 marks]
1 mark each modems: • Converts digital data into analogue for transmission down phone lines // Converts analogue data into digital after transmission down phone lines dedicated lines: • Used to provide a direct / private connection which therefore provides faster transmission
A company has multiple sites in different cities. The company has drivers who deliver products to customers. Each driver can connect to the company’s WAN (Wide Area Network) whilst out of the office using a smartphone.
(a) State two ways that a WAN is different to a LAN (Local Area Network). 2 marks
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(b) The smartphones use the cell phone network to connect to the WAN. 4 marks
Explain how data is transmitted using the cell phone network.
(c) Devices that connect to the WAN have an IP address. 6 marks
Complete the following description of IP addresses by writing the missing words.
IPv4 is displayed as four groups of 8-bit numbers separated by ______ .
Each IPv4 address is 32 bits.
IPv6 is made of eight groups of 4 ______ numbers separated by colons.
Multiple consecutive groups of ______ can be replaced with a double colon.
Each IPv6 address is ______ bits.
A ______ IP address can change each time the computer connects to a network.
A ______ IP address can only be accessed by other devices in the same LAN and is assigned by the router within the LAN.
(d) The main office for the company has four wired computers, one server, two printers, one central switch and a device providing a single point of access for the internet. The network is set up as a star topology. 4 marks
Draw the topology for the main office network. Label all devices.
(e) Describe the role of a switch in a network. 3 marks
Show mark scheme
6(a) [2 marks]
1 mark each to max 2 • In a WAN devices can connect over a larger geographical area in a LAN devices connect over a smaller geographical area • A WAN may use non-dedicated hardware the hardware in a LAN is usually dedicated • A WAN uses external / not company owned transmission media // the transmission media for a LAN is usually company owned
6(b) [4 marks]
1 mark each to max 4 e.g. • Land is split into cells designed for maximum line of sight • Each cell has a tower with an antenna which receives and transmits data • Data is transmitted between the tower and the phone • Data transmission is wireless using low power radio signals/frequencies • Multiple devices can communicate simultaneously with the same tower
6(c) [6 marks]
1 mark for each correct word • full stops • hexadecimal • zeros • 128 • dynamic • private IPv4 is made of four groups of 8-bit numbers separated by full stops . Each IPv4 address is 32 bits. IPv6 is made of eight groups of 4 hexadecimal numbers separated by colons. Multiple consecutive groups of zeros can be replaced with a double colon. Each IPv6 address is 128 bits. A dynamic IP address can change each time the computer connects to a network. A private IP address can only be accessed by other devices in the same LAN and is assigned by the router within the LAN.
6(d) [4 marks]
1 mark each • Server directly connected to the switch • Four labelled computers all connected directly to the switch • Two printers each directly connected to the switch / server / a computer • Router / modem directly connected to the switch / server for internet access e.g. Example only
6(e) [3 marks]
1 mark each to max 3 e.g. • To store the MAC addresses of devices connected to it • To receive packets from devices • To forward packets directly to the intended recipient • To provide a central point of connection for the network • to enable connected devices to communicate
A computer is connected to a Local Area Network (LAN) that connects to a Wide Area Network (WAN).
(a) Describe the characteristics of a WAN. 2 marks
(b) Copper cable can be used to transmit data in a network. 4 marks
Complete the table by identifying and describing two other transmission media that can be used to transfer data in the WAN.
| Transmission medium | Description |
|---|---|
(c) The computer on the LAN is used for real-time video conferences, where people connected to the internet communicate in real-time using video and audio. 4 marks
Explain how bit streaming is used in a real-time video conference.
(d) The LAN has a router. The router has a public IP address and a private IP address.
(i) State the purpose of a public IP address and a private IP address. 2 marks
Public IP address
Private IP address
(ii) The LAN uses subnetting. 2 marks
Describe the purpose of subnetting in a network.
Show mark scheme
9(a) [2 marks]
1 mark for each bullet point ( max 2 ) • A WAN covers a large geographical area • External/public infrastructure is used • Non-dedicated hardware
9(b) [4 marks]
1 mark for correct media 1 mark for matching description e.g. • Fibre optic • Transmits data as pulses of light • Radio waves / microwaves • Transmits electromagnetic waves on different frequencies
9(c) [4 marks]
1 mark for each bullet point ( max 4 ) • Data is compressed before transmitting • The video and audio are transmitted continuously as a series of bits • The video is uploaded to a media server • On download, the media server sends the data to a buffer • The buffer stores data from server until the receiving device can process it • The receiving device receives the bit stream from the buffer
9(d)(i) [2 marks]
1 mark for public IP address and 1 mark for private IP address: Public IP address: • So that the router is visible to the Internet/external network/WAN Private IP address: • So that the router is identified to computers within the LAN
9(d)(ii) [2 marks]
1 mark for each bullet point ( max 2 ) • It allows the network to be divided into smaller networks • … which reduces traffic in some parts of the network // reduces congestion • … because traffic only travels through the parts necessary • … which hides the complexity of network • … and allows for easier maintenance of the network
A bank allows customers to access their accounts using an application that they can download onto a device such as a smartphone.
(a) The system that allows customers to access their accounts using the application is a client-server model. 4 marks
Describe the roles of the different devices in this model.
(b) The bank wants to protect the integrity of its data while transferring the data to other banks. 5 marks
Parity check is one example of data verification.
Complete the description of parity check when Computer A is transmitting data to Computer B.
Computer A and Computer B agree on whether to use
parity. Computer A divides the data into groups of ______ . The
number of 1s in each group is counted. If the agreed parity is
and the group has an even number of 1s, a parity bit of 1 is appended, otherwise a parity bit
of 0 is appended.
In a parity ______ check the bytes are grouped together, for
example in a grid. The number of 1s in each column (bit position) is counted. A bit is assigned
to each column to make the column match the parity. These parity bits are transmitted with
the data as a parity ______ .
(c) The bank also needs to keep its customers’ data private and secure.
(i) The bank’s network has a firewall. 3 marks
Explain how a firewall can help protect the customers’ data.
(ii) Customers need to use biometric authentication to access their accounts. 4 marks
One biometric authentication method is facial recognition.
Facial recognition uses Artificial Intelligence (AI).
Describe how AI is used in facial recognition.
Show mark scheme
5(a) [4 marks]
1 mark each: Identification of server in the bank scenario Description e.g. Receives requests, processes the requests Identification of client in bank scenario Description e.g. Sends request to the server, waits and outputs the response
5(b) [5 marks]
1 mark for each correctly completed term: odd or even 7-bits odd block byte Computer A and Computer B agree on whether to use odd or even parity. Computer A divides the data into groups of 7-bits . The number of 1s in each group is counted. If the agreed parity is odd and the group has an even number of 1s a parity bit of 1 is appended, otherwise a parity bit of 0 is appended. In a parity block check the bytes are grouped together, for example in a grid. The number of 1s in each column (bit position) is counted. A bit is assigned to each column to make the column match the parity. These parity bits are transmitted with the data as a parity byte .
5(c)(i) [3 marks]
1 mark each to max 3 : Compares all incoming and outgoing transmissions ... against set criteria/whitelist/blacklist Blocks all transmissions that do not meet rules Blocks data entering from specific ports Blocks unauthorised/unknown internal software transmitting data
5(c)(ii) [4 marks]
1 mark each to max 4 : e.g. Captures an image of the face Uses image recognition Trained to identify the features of a face in an image … using a large number of images Analyse images for facial features Uses the probability of a match
A business is creating a local area network (LAN) in its office.
(a) The business is deciding which topology to use. 5 marks
| Tick (✓) one or more boxes in each row to identify t describes. | the topology, | , or topologie | es, each sta |
|---|---|---|---|
| Statement | Bus | Star | Mesh |
| all devices connect to one central device | |||
| all devices connect to a central cable | |||
| multiple paths for the packets to travel along | |||
| robust against damage because if any line fails, the rest of the network retains full functionality |
|||
| most likely to lose data through collisions |
(b) The LAN will connect to the internet through a router. The router has a public IPv6 address.
(i) State why the router has a public IP address. 1 mark
(ii) One difference between an IPv4 and IPv6 address is that the numbers in an IPv4 address are separated by full stops and in an IPv6 address they are separated by colons. 2 marks
Identify two other differences between an IPv4 and IPv6 address.
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Show mark scheme
8(a) [5 marks]
1 mark for each correct row: Statement Bus Star Mesh all devices connect to one central device all devices connect to a central cable multiple paths for the packets to travel robust against damage because if any line fails, the rest of the network retains full functionality most likely to lose data through collisions
8(b)(i) [1 mark]
1 mark for: to be visible to and accessible by other devices on the internet
8(b)(ii) [2 marks]
1 mark each: IPv4 has 4 groups of digits whilst IPv6 has 8 groups IPv4 is usually represented in denary whilst IPv6 is usually represented in hexadecimal IPv4 groups are between 0 and 255 whilst IPv6 is between 0 and FFFF IPv4 is 32 bits whilst IPv6 is 128 bits
A multimedia design company has an office with a LAN (local area network). The LAN can have up to 20 devices connected with cables and other devices connected using wireless access.
(a) The company has private cloud storage for its employees to store their work.
(i) Define the term private cloud . 1 mark
(ii) Describe the benefits to the company of using private cloud storage instead of public cloud storage. 3 marks
(b) Part of the internal structure of the wired LAN is a star topology. 2 marks
Explain how packets are transmitted between two devices in a star topology.
(c) A different part of the network uses the Ethernet protocol.
(i) A collision is detected. 2 marks
Describe how the collision is managed using Carrier Sense Multiple Access/Collision Detection (CSMA/CD).
(ii) Identify two drawbacks of using CSMA/CD. 2 marks
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(d) The devices in the office have static private IP addresses. 1 mark
State what is meant by a static private IP address .
Show mark scheme
5(a)(i) [1 mark]
1 mark for: Dedicated/bespoke services/storage on a remote server only available to company
5(a)(ii) [3 marks]
1 mark each to max 3 : e.g. Not reliant on a third party … gives greater control over security/privacy … gives greater control over backup Storage can be tailored/scalable to company requirements// an example e.g. the amount of storage accessible/ facilitating the sharing of files
5(b) [2 marks]
1 mark each: Sending computer transmits packets directly to switch/router/central device Switch/router/central device checks destination address of packet and forwards directly to that device
5(c)(i) [2 marks]
1 mark each to max 2 : Jamming signal is transmitted by the sending device Transmission is aborted The sending device waits a random time before trying to send data again ... ... if further collisions occur the wait time is increased
5(c)(ii) [1 mark]
1 mark each to max 2 : Random time increased each time so can be infinite waiting May be constant jamming signal so nothing ever sends Certain nodes cannot be prioritised High power consumption Only suitable for short distance network // limited distance Not scalable // more nodes means exponentially longer waiting times
5(d)
1 mark for: Static means the IP for that device does not change and Private means it can only be accessed/seen/used within the LAN
A school has a Local Area Network (LAN).
(a) The LAN connects to the internet using a router. 3 marks 3 marks
Describe the function of a router in a network.
| Complete the following tab used to support the LAN. | ble by writing the purpose of each of these other hardware devices |
|---|---|
| Hardware device | Purpose |
| switch | ______ |
| Wireless Access Point (WAP) |
______ |
| bridge | ______ |
Show mark scheme
2(a) [3 marks]
1 mark for each bullet point ( max 3 ) • Receives packets from internet / external network • Implements a firewall • Analyses the destination IP address of each packet • Forwards the packet towards its destination // send packets onto local network or external network • ...using the routing table • Maintains / updates the routing • Allocates private IP addresses • Finds the most efficient route to the destination • Changes the packet format for transmission over the next network // • Network Address Translation (NAT):NAT is a technique used by routers to allow multiple devices in a private local area network (LAN) to share a single public IP address.
2(b) [3 marks]
Switch: 1 mark for each bullet point ( max 1 ) • To allow two or more devices to communicate with one another • To connect individual devices to each other • To receive transmissions and forward them to their destination Wireless Access Point (WAP): 1 mark for each bullet point ( max 1 ) • To allow connection of devices (to the central device) using radio signals / Wi-Fi • To allow the central device to send / receive radio signals / Wi-Fi signals • To allow wireless enabled devices to connect to a wired network Bridge: 1 mark for each bullet point ( max 1 ) • To connect two LANs / segments with the same protocol • To transmit data between two networks with the same protocol
2(c) [2 marks]
1 mark for each bullet point ( max 2 ) • The students cannot access their files without a reliable internet connection • The amount of space for no payment may be limited so students will have to purchase more space if needed • The students do not have control over the backup (or security) of their work // the students are dependent on a third party for the (security and) backing up of their work
2(d) [2 marks]
1 mark for each advantage and 1 mark for valid corresponding expansion • Star topology is more resilient to faults • …because there is no single cable and leads to less disruption to teaching • Higher performance as fewer collisions • ...because each device in the classroom is only connected to the switch • Easier to add new nodes • …because each device in the classroom connects directly to the switch • Easier to fault find compared to bus topology
A Local Area Network (LAN) contains four devices:
a router
two laptop computers
a server.
(a) The server has the IP address 192.168.3.2 Explain why this is not an IPv6 address. 2 marks
(b) (i) The LAN is set up as a star topology. 2 marks
Draw a diagram of the topology of the LAN.
(ii) Explain how data is transmitted between the two laptops in the LAN. 2 marks
(iii) Subnetting can be used to separate a network into logical segments. 4 marks
Describe two other reasons why subnetting is used in a network.
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(c) State three tasks performed by devices to deal with collisions when using the Carrier Sense Multiple Access / Collision Detection (CSMA/CD) protocol in a network. 3 marks
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(d) The following incomplete table contains types of IP addresses and their descriptions. 4 marks
Complete the table by writing the missing types of IP addresses and the missing descriptions.
| Type of IP address | Description |
|---|---|
| an IP address that is assigned to a device to allow direct access on the internet |
|
| static IP address | |
| an IP address used for internal LAN communication only |
|
| dynamic IP address |
Show mark scheme
7(a) [2 marks]
1 mark for each bullet point (max 2 ) • Only has four groups of digits // IPv6 has eight groups • Uses dotted notation instead of colons • Because it is a 32 bit / 4 byte address // IPv6 is 128 bits / 16 bytes
7(b)(i) [2 marks]
1 mark for server only connected to router 1 mark for two laptop computers connected only to router
7(b)(ii) [2 marks]
1 mark for each bullet point ( max 2 ) • The data from the sending laptop is transmitted to the router • The data has address of recipient • The router determines recipient’s destination address • ... by using a routing table • The router transmits data directly / only to recipient
7(b)(iii) [4 marks]
1 mark for each use ( max 2 ) and 1 mark for corresponding expansion ( max 2 ) • To improve the security of the LAN • … so that devices do not receive unintended data • … so that a compromised device does not expose the whole network • ... so not all devices can access all segments • To make the network management easier • … because faults can be isolated more efficiently • ... by appropriate example • To make the network easier to expand // For better control of network growth • … by allowing for greater range of IP addresses to be available • To improve network performance • To reduce network congestion • … by localising network communications // by dividing data between segments • … so that devices are not flooded with data • … because data sent between devices on the same subnet stays within the subnet
7(c) [3 marks]
1 mark for each bullet point ( max 3 ) • To monitor the communications channel • To send data only when there is no data being transmitted / the line is quiet / idle • To detect a collision and then stop transmissions of further data // transmit a jamming signal • To calculate a random wait time / back-off time • ... then retransmit the data after that random wait time • Increase random time if multiple collisions
7(d) [4 marks]
1 mark for each highlighted area Type of IP address Description an IP address that is assigned to a device public IP address to allow direct access on the internet an IP address that is fixed / doesn’t static IP address change each time a device re-joins a LAN / network an IP address used for internal LAN private IP address communication only an IP address that may be refreshed / dynamic IP address changed each time a device re-joins a LAN / network
A company sells online Computer Science courses to students in different countries.
The courses are stored on a public cloud.
(a) (i) Explain why the company uses a public cloud to store these courses. 2 marks
(ii) Describe two disadvantages of storing data on a public cloud compared to storing data on a server in a Local Area Network (LAN). 4 marks
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(iii) State how the following security measures can be used to protect computer systems. 3 marks
Firewall
Encryption
Passwords
Show mark scheme
3(a)(i) [2 marks]
1 mark for each bullet point ( max 2 ). • Courses must be available to anyone who wishes to follow them • Courses must be available on the internet • Company is willing to share infrastructure with other companies (public) • …which is more economic for the company
3(a)(ii) [4 marks]
1 mark for each bullet point ( max 2 for each disadvantage). • There could be a possible loss of control unlike the LAN • …because the data is stored on a remote infrastructure / someone else’s infrastructure • …reliance on external agency to complete tasks, e.g. backups, security • Requires reliable internet connection • …to ensure access to the remote data, more likely with LAN • Increased recurring costs • ...as cloud provider charges must be paid, costs for LAN once only.
3(a)(iii) [3 marks]
1 mark each for firewall, encryption and passwords. Firewall: • Monitors incoming and outgoing traffic and rejects any traffic that does not meet the set rules Encryption: • Ensures that if data is intercepted / obtained it cannot be understood without the decryption key Passwords: • Ensures only users with the correct password can access the resources // prevents unauthorised access
3(b)(i) [1 mark]
1 mark for both 1:M relationships as follows:
3(b)(ii) [4 marks]
1 mark for each bullet point. • SELECT Count(CourseID) • AS NumOfCourses • FROM COURSE_SCHEDULE • WHERE DateStarted > "09/09/23"; SELECT Count(CourseID) AS NumOfCourses FROM COURSE_SCHEDULE WHERE DateStarted > "09/09/23";
3(c) [4 marks]
1 mark for each bullet point. • The administrator completes a visual check / checks by eye • …that the tutor identifier input matches the tutor identifier on the original document • Double entry check // the administrator (or a second person) enters the number a second time • …and the system compares it with the first entry
A networked closed‑circuit television (CCTV) system in a house uses sensors and cameras to detect the presence of a person. It then tracks the person and records a video of their movements.
Data from the CCTV cameras is transmitted to a central computer.
(a) This computer has both Read Only Memory (ROM) and Random Access Memory (RAM).
(i) Describe the contents of the ROM in the central computer. 2 marks
(ii) The central computer has Dynamic RAM (DRAM). 2 marks
Identify two advantages of using DRAM instead of Static RAM (SRAM).
1
2
(b) The central computer stores the video files on secondary storage. 4 marks
Describe two reasons why magnetic storage is more appropriate than solid state storage for this computer.
1
2
(c) The CCTV system uses Artificial Intelligence (AI) to identify the presence of a person in the house and to track their movements. 3 marks
Describe how AI is used in this system.
(d) The CCTV cameras are connected to a network and transfer their data wirelessly to the central computer.
(i) Each device on the network has an IP address. 5 marks
Complete the description of IP addresses.
An IPv4 address contains ______ groups of digits. Each group is
represented in ______ bits and the groups are separated by full stops.
An IPv6 address contains ______ groups of digits. Each group is
represented in ______ bits. Multiple groups that only contain zeros
can be replaced with a ______ .
(ii) The network makes use of subnetting. 4 marks
Describe two benefits of subnetting a network.
1
2
Show mark scheme
4(a)(i)
1 mark each to max 2 Stores the bootstrap program // start-up instructions for the central computer // BIOS Stores the start-up instructions for the CCTV system/cameras // firmware for CCTV Stores the kernel of the Operating System // stores parts of the Operating System
4(a)(ii) [2 marks]
1 mark each to max 2 Costs less per unit Higher storage density Simple design – uses fewer transistors
4(b) [3 marks]
1 mark for reason, 1mark for application/justification The computer will have a large number of read/write operations because it is working all the time .. magnetic storage has more longevity Magnetic storage costs less per storage unit … videos are large files and therefore very large storage capacity is required
4(c) [5 marks]
1 mark each to max 3 Examples: Uses image recognition Monitors every image taken to identify matching images/shapes/features to a 'person' … … starts recording to secondary storage/permanently when a person is identified System identifies direction of movement of person and uses this to decide where/how to move the camera/record System identifies other cameras to start recording based on direction of movement
4(d)(i)
1 mark for each term An IPv4 address contains 4 groups of digits. Each group is represented in 8 bits and the groups are separated by full stops. An IPv6 address contains 8 groups of digits. Each group is represented in 16 bits. Multiple groups that only contain zeros can be replaced with a :: // double colon .
4(d)(ii) [4 marks]
1 mark for identification, 1mark for expansion e.g. Reduce amount of traffic in a network // improve network speed Data stays in its subnet so it does not travel as far Improves network security .. so that not all devices can access all areas of the network Allows for easier maintenance … because only one subnetwork may need taking down/changing while the rest of the network can continue
A company has a LAN (local area network).
(a) Give two benefits of connecting computers to a LAN. 2 marks
1
2
(b) Give two characteristics of a LAN. 2 marks
1
2
(c) One of the company’s offices has one server and four computers connected in a star topology. 2 marks
Draw a diagram to show the layout of the office’s star topology.
Show mark scheme
1(a) [2 marks]
1 mark each to max 2 Allows the sharing of files/data // Allows communication between the devices Allows the sharing of resources e.g. hardware / software (applications) Allows central management // by example, backup, security, etc.
1(b) [2 marks]
1 mark each to max 2 Covers a small geographical area The infrastructure is privately owned // not controlled by external organisations
1(c)
1 mark each to max 2 Each computer directly connected only to the server ... ... all components correctly labelled Computer Computer 4 1 Server Computer Computer
1(d) [3 marks]
1 mark each to max 3 A protocol (suite) For data transmission over standard / universal wired / cabled network connections Uses Carrier Sense Multiple Access / Collision Detection (CSMA/CD) Data is transmitted in frames … each frame has a source and destination (IP/MAC) address ... and error checking data (so damaged frames can be resent)
1(e) [2 marks]
1 mark each The server performs minimal / some processing for the client The clients also do most of their own processing/work independently // most of the resources are installed locally
A university has two sites. Each site has several computer rooms. The computers are all connected as a WAN (wide area network).
(a) Identify two differences between a WAN and a LAN (local area network). 2 marks
1
2
(b) The network uses different topologies in different areas of the sites. In one building there are five computers connected in a mesh topology.
(i) Describe what is meant by a mesh topology. 2 marks
(ii) Give two advantages of using a mesh topology instead of a bus topology. 2 marks
1
2
(c) The computers in one room are set up as thin-clients in a client-server model. 2 marks
Describe the role of the different computers in this model.
Show mark scheme
2(a)
1 mark each to max 2 WAN covers a large geographica l area and LAN covers a small geographical area LAN connections between devices are usually physical, whereas the WAN connections are often virtual A LAN has a high data transfer rate, whereas a WAN has a low data transfer rate The ownership of a LAN is private; the ownership of a WAN can be private or public LAN is usually more secure than a WAN because protection is easier to implement
2(b)(i) [2 marks]
1 mark each to max 2 All computers are connected to at least one other device There are multiple routes between devices The computers can act as relays, passing packets on towards the final destination
2(b)(ii)
1 mark each to max 2 If one line goes down there are more routes available Improved security as not using one main line No/fewer collisions New nodes can be added without interruption or interfering with other nodes More secure because data is sent over a dedicated connection
2(c) [4 marks]
1 mark each to max 2 Server performs all processes required by the task and/or data storage Clients only sends requests to the server and displays the returned results
2(d) [3 marks]
1 mark each to max 4 Examples: Some students might only have one sort of connection on their device Wired provides better performance for the student's device ... for example, enabling faster access to university databases There will be less interference if students connect via a cable Students can transmit private/confidential data/work securely ... for example, their final dissertation Wireless connection means that the students can use their devices in different rooms/sites/outside/anywhere more freely // student devices can be portable Wireless connection enables the students to bring multiple devices // bring their own devices // change devices
2(e) [5 marks]
1 mark for identification IP address is made up of a network ID and a host ID 1 mark each to max 2 for description Each device in a subnetwork has the same network ID // Each subnetwork has a different network ID Every device in each subnetwork has a different host ID but the same network ID // the host ID uniquely identifies the device within the subnetwork
(a) State what is meant by the stored program concept in the Von Neumann model of a computer system. 1 mark
(b) A Central Processing Unit (CPU) contains several special purpose registers and other components.
(i) State the role of the following registers. 3 marks 1 mark
Program Counter (PC)
Index Register (IX)
Status Register (SR)
| Tick () one box in each row to iden | ntify the system bu | us used by each C | CPU component. |
|---|---|---|---|
| CPU component | Data bus | Address bus | Control bus |
| System clock | |||
| Memory Address Register (MAR) |
(iii) Describe the purpose of the Control Unit (CU) in a CPU. 2 marks
(c) Describe the purpose of an interrupt in a computer system. 2 marks
(d) Identify two causes of a software interrupt. 2 marks
1
2
Show mark scheme
5(a) [1 mark]
Instructions and data are stored in the same memory space / in main memory.
5(b)(i) [3 marks]
1 mark for each special purpose register: Program Counter (PC): • to store the address / location / memory location of the next instruction to be fetched Index Register (IX): • to store a value that is added to an address to give another address Status Register (SR): • to store flags which are set by events // from the results of arithmetic and logic operations and interrupt flags
5(b)(ii) [1 mark]
1 mark for both rows: CPU component Data bus Address bus Control bus ✓ System clock ✓ Memory Address Register (MAR)
5(b)(iii) [2 marks]
1 mark for each bullet point ( max 2 ): • to coordinate / synchronise the actions of other components in the CPU • to send / receive control signals along the control bus • to manage the execution of instructions (in sequence) • to control the communication between the components of the CPU
5(c) [2 marks]
1 mark for each bullet point: • to send a signal from a device or process • ... seeking the attention of the processor
5(d) [2 marks]
1 mark for each bullet point ( max 2 ). For example: • division by zero // runtime error in a program • attempt to access an invalid memory location • array index out of bounds • stack overflow
A relational database, GARDEN, has the following tables:
OWNER(OwnerID, FirstName, TelephoneNo, TreeID, TreePosition)
TREE(TreeID, ScientificName, MaxHeight, FastGrowing)
(a) The database is not in Third Normal Form (3NF). 3 marks 3 marks
Explain how the database can be normalised to 3NF.
| ructured Query Language (SQ owing data: | QL) script to add a new record |
|---|---|
| Attribute | Value |
TreeID |
LOW_1276 |
ScientificName |
Salix_Alba |
MaxHeight |
30.00 |
FastGrowing |
TRUE |
(c) State what is meant by a candidate key in a relational database. 1 mark
Show mark scheme
5(a) [3 marks]
1 mark for each bullet point (max 3) : Solution 1: • removing the many-to-many relationship between Owner and Tree • ... by removing TreeID and TreePosition from the Owner table • ... and creating a linking table between Owner and Tree • ... that contains OwnerID, TreeID and TreePosition • ... (composite) primary key of the linking table should be OwnerID and TreeID // insert a named new primary key in the linking table Solution 2: • removing the many-to-many relationship between Owner and Tree • move TreePosition into TREE table • ... put OwnerID into TREE table • create a new table with suitable name (for the species of tree) • ... containing ScientificName, MaxHeight and FastGrowing • ... with ScientificName as primary key // or another suitable primary key
5(b) [3 marks]
1 mark for each bullet point: • INSERT INTO TREE • VALUES ( ) and correct values • Values in correct order Option 1: INSERT INTO TREE(TreeID, ScientificName, MaxHeight, FastGrowing) VALUES('LOW_1276', 'Salix_Alba', 30.00, TRUE); Option 2: INSERT INTO TREE VALUES('LOW_1276', 'Salix_Alba', 30.00, TRUE);
5(c) [1 mark]
1 mark for: An attribute / field (or set of attributes / fields) that could be a primary key
5(d)(i) [2 marks]
1 mark for description • stores metadata about the database 1 mark for a correct example For example: • field / attribute names • table name • validation rules • data types • primary keys // foreign keys • relationships
5(d)(ii) [2 marks]
1 mark for each bullet point (max 2) : • the overview of a database structure • models the problem / situation • ... by using methods such as an ER diagram • independent of any particular DBMS
(a) Draw a logic circuit for the logic expression: 3 marks
X = NOT ((NOT ( A AND B )) OR (NOT ( B AND C )))
A
C
(b) Complete the truth table for the logic expression: 2 marks
Y = (NOT P AND Q ) OR ( Q AND NOT R )
| P | Q | R | Working space | Y |
|---|---|---|---|---|
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 | ||
 |
Show mark scheme
5(a) [3 marks]
1 mark for each bullet point: • NOT (A AND B) • NOT (B AND C) • NOT(NOT(A AND B) OR NOT(B AND C))
5(b) [2 marks]
1 mark for each set of highlighted rows. 0 0 0 0 0 0 1 0 0 1 0 1 0 1 1 1 1 0 0 0 1 0 1 0 1 1 0 1 1 1 1 0
(a) The following incomplete table contains four network devices and their descriptions. 4 marks
| Complete the table | by writing the missing devices and missing descriptions. |
|---|---|
| Device | Description |
| ______ | Receives and sends data between two networks operating on the same protocol |
| Wireless Network Interface Card (WNIC) |
______ |
| ______ | Restores the digital signal so it can be transmitted over greater distances |
| Wireless Access Point (WAP) |
______ |
(b) Describe three differences between fibre-optic cables and copper cables. 3 marks
1
2
3
(c) Ethernet uses Carrier Sense Multiple Access/Collision Detection (CSMA/CD). 4 marks
Describe CSMA/CD.
Show mark scheme
9(a) [3 marks]
1 mark for each completed name or description Device Description Receives and sends data between two networks Router operating on the same protocol Wireless Hardware component that allows a device to connect to Network a wireless network // Provides a MAC address to the Interface Card device to identify it on the wireless network (WNIC) Restores the digital signal so it can be transmitted over Repeater greater distances Wireless Hardware component that provides radio Access Point communication from the central device to nodes on the network (and vice versa) (WAP)
9(b)
1 mark for each difference e.g. Fibre optic data is transmitted using light, copper cable through electrical signals Fibre optic has higher bandwidth than copper cable // Fibre optic has higher transmission rates than copper cable Fibre optic has smaller risk of (noise) interference than copper cable Fibre optic can be used over longer distances than copper cable before repeaters are needed Fibre optic is much more difficult to hack into than copper cable Fibre optic is more prone to damage than copper cable
9(c) [4 marks]
1 mark per point to max 4 A workstation / node (wishing to transmit) listens to the communication channel …data is only sent when the channel is free // ... if channel is free data is sent Because there is more than one computer connected to the same transmission medium ... two workstations can start to transmit at the same time, causing a collision If a collision happens, the workstations send a (jamming) signal / abort transmission …and each waits a random amount of time before attempting to resend
A company uses cloud computing.
(a) Define cloud computing. 1 mark
(b) State what is meant by a public cloud and a private cloud. 2 marks
Public cloud
Private cloud
(c) Give two benefits and one drawback of using cloud computing. 3 marks
Benefit 1
Benefit 2
Drawback
Show mark scheme
8(a) [1 mark]
Accessing a service/files/software on a remote server
8(b) [2 marks]
1 mark each from: Public e.g. Computing services offered by 3rd party provider over the public Internet Public is open/available to anyone with the appropriate equipment/software/credentials Private e.g. Computing services offered either over the Internet or a private internal network Only available to select users not the general public Private is a dedicated/bespoke system only accessible for/from the organisation
8(c) [3 marks]
1 mark for each benefit to max 2 e.g. Can be accessed anywhere with Internet access Do not need to install security // security might be better Do not need to perform backups Do not need to buy specific software/hardware Can easily share documents Can have multiple people working on the same document 1 mark for drawback e.g. You cannot access it if no internet access Reliant on someone else to backup Reliant on someone else for security // can have poorer security Cannot access if server goes down
A school is setting up a network within one of its buildings.
(a) State whether the network will be a LAN (local area network) or a WAN (wide area network). 3 marks
Justify your choice.
(b) One classroom in the building has 30 computers. The computers need to be connected to the network. Each computer has a network interface card (NIC). 2 marks
Identify two possible devices that can be used to physically connect the 30 computers to the rest of the network.
1
2
(c) The school has several laptops. Each laptop has a Wireless Network Interface Card (WNIC). 4 marks
Describe the functions of a Wireless Network Interface Card.
Show mark scheme
8(a) [3 marks]
1 mark per bullet point LAN • Small geographical area • No leasing external infrastructure / transmission media // does not use • internet to transmit within the building
8(b) [2 marks]
1 mark per item router • switch • hub •
8(c) [4 marks]
1 mark per bullet point to max 4 Provide interface to wireless network • … as an antenna • Receives analogue radio waves • … convert them to digital / binary • Checks incoming transmissions for correct MAC / IP address • … ignore transmissions not intended for it • Encrypts / encodes the data • Decrypts / decodes the data • Takes digital/binary input and converts to analogue waves • … sends the radio waves via the antenna •
Andy likes to play computer games.
(a) Andy uses several input devices to play the games. These include a keyboard and a microphone. 3 marks
Describe the principal operation of a microphone.
(b) Andy plays some of the computer games over the internet. He has several devices that connect wirelessly to the router in his house.
(i) Identify the topology of Andy’s home network. Justify your choice. 2 marks
Topology
Justification
(ii) The router has a wireless access point (WAP) to allow the devices to connect wirelessly. 3 marks
Identify three functions of the router in Andy’s network.
1
2
3
Show mark scheme
3(a)
1 mark for each bullet point to max 3 The microphone has a diaphragm / ribbon • The incoming sound waves cause vibrations of the diaphragm • … causing a coil to move past a magnet // causing a magnet to move • past a coil (dynamic microphone) // changing the capacitance (condenser microphone) // deforms the crystal (crystal microphone) An electrical signal is produced •
3(b)(i) [2 marks]
1 mark for identification of star topology 1 mark for justification Devices are connected directly to the router independently // all devices are only connected to the router
3(b)(ii) [3 marks]
1 mark for each correct function to max 3 To receive packets from devices or the Internet • To forward / route packets to the destination • To find the destination of the packet • To assign / allocate private IP addresses to devices on LAN • To store / update / maintain a routing table • To find the most efficient path to the destination • To maintain a table of MAC and IP addresses •
A school is setting up a network within one of its buildings.
(a) State whether the network will be a LAN (local area network) or a WAN (wide area network). 3 marks
Justify your choice.
(b) One classroom in the building has 30 computers. The computers need to be connected to the network. Each computer has a network interface card (NIC). 2 marks
Identify two possible devices that can be used to physically connect the 30 computers to the rest of the network.
1
2
(c) The school has several laptops. Each laptop has a Wireless Network Interface Card (WNIC). 4 marks
Describe the functions of a Wireless Network Interface Card.
Show mark scheme
8(a) [3 marks]
1 mark per bullet point LAN • Small geographical area • No leasing external infrastructure / transmission media // does not use • internet to transmit within the building
8(b) [2 marks]
1 mark per item router • switch • hub •
8(c) [4 marks]
1 mark per bullet point to max 4 Provide interface to wireless network • … as an antenna • Receives analogue radio waves • … convert them to digital / binary • Checks incoming transmissions for correct MAC / IP address • … ignore transmissions not intended for it • Encrypts / encodes the data • Decrypts / decodes the data • Takes digital/binary input and converts to analogue waves • … sends the radio waves via the antenna •
Melinda and her friends set up a peer-to-peer network between their computers to share data.
(a) Describe the key features of a peer-to-peer network. 2 marks
(b) Describe two drawbacks to Melinda and her friends of using a peer-to-peer network. 4 marks
1
2
(c) Melinda connects her laptop to the internet through her router. 2 marks
| (i) Tick (3) one box in each row to identify whether t not. | the task is perform | med by the router or |
|---|---|---|
| Task | Performed by router |
Not performed by router |
| Receives packets from devices | ||
| Finds the IP address of a Uniform Resource Locator (URL) | ||
| Directs each packet to all devices attached to it | ||
| Stores the IP and/or MAC address of all devices attached to it |
(ii) Melinda mainly uses the internet to watch films and play computer games. 3 marks
| Tick (3) one bo or wireless netw | ox to identify whe work and justify y |
|---|---|
| Wired | |
| Wireless |
Justification
(d) Melinda sends emails from her webmail account (email account accessed through a website). 3 marks
Explain whether Melinda is using the internet, or the World Wide Web (WWW), or both.
Show mark scheme
4(a) [2 marks]
1 mark per bullet point to max 2 All computers are of equal status • Each computer provides access to resources and data // data is • distributed Computers can communicate and share resources • Each computer is responsible for its own security •
4(b) [4 marks]
1 mark per bullet point to max 2 per drawback Reduced security // no central management of security • … only as secure as the weakest computer on the network • … each computer is at risk from viruses from other computers • No central management of backup • ... if the data from one computer is not backed up it is lost to all of them • No central management of files/software • … consistency may be difficult to maintain • … each computer may have different software from the others • Individual computers may respond slower • … because they are being accessed by other computers • In order to share files etc. all the computers involved need to be switched • on ... so the files etc. may not be always available •
4(c)(i) [2 marks]
1 mark for first 2 ticks, 1 mark for last 2 (shaded) Performed Not performed Task by router by router Receives packets from devices Finds the IP address of a Uniform Resource Locator (URL) Directs each packet to all devices attached to it Stores the IP and/or MAC address of all devices attached to it
4(c)(ii) [3 marks]
1 mark per bullet point for justification up to max 3 No mark for identification of wired/wireless Wired Faster connection // higher bandwidth • …. needed as she is downloading/streaming large files • … less time waiting / less latency / fewer delays • More reliable / stable connection • … is less susceptible to issues with distance/walls/interference • More secure • Wireless Freedom of movement • … can move between different rooms with a mobile device and still • receive/transmit data … no need of a physical connection • Easily expanded if friends want to access the same network • Less cabling / expertise is needed • ... making the initial setup less expensive •
4(d) [2 marks]
1 mark for identifying that she is using both. 1 mark per bullet point for justification using internet because sending data on the infrastructure • using WWW because accessing a website (that is stored on a web • server operated by the webmail) that is part of the WWW
Seth uses a computer for work.
(a) Complete the following descriptions of internal components of a computer by writing the missing terms. 5 marks
The ______ transmits the signals to coordinate events based
on the electronic pulses of the ______ .
The ______ carries data to the components, while the
______ carries the address where data needs to be written to
or read from.
The ______ performs mathematical operations and
logical comparisons.
(b) Describe the ways in which the following factors can affect the performance of his laptop computer. 4 marks
Number of cores
Clock speed
(c) Seth accesses both software and data using cloud computing.
(i) Give two benefits of storing data using cloud computing. 2 marks
1
2
(ii) Give two drawbacks of Seth using cloud computing. 2 marks
1
2
(d) Draw one line from each term to its most appropriate description. 4 marks
Term Description
It is only visible to devices within the Local Area Network (LAN)
Public IP address
Private IP address
Dynamic IP address
Static IP address
It increments by 1 each time the device connects to the internet
A new one is reallocated each time a device connects to the internet
It can only be allocated to a router
It is visible to any device on the internet
It does not change each time a device connects to the internet
Show mark scheme
5(a)
1 mark for each term correctly inserted The control unit/bus transmits the signals to coordinate events based on the pulses of the ( system) clock . The data bus carries data to components, while the address bus carries the address where data is being written to or read from. The arithmetic logic unit/ALU performs mathematical operations and logical comparisons.
5(b) [4 marks]
1 mark per bullet point to max 3 per factor. max 4 overall. Number of cores: Each core processes one instruction per clock pulse • More/multiple cores mean that sequences of instructions can be split • between them … and so more than one instruction is executed per clock pulse // more • sequences of instructions can be run at the same time More cores decreases the time taken to complete task • Clock speed: Each instruction is executed on a clock pulse // one F-E cycle is run on • each clock pulse ... so the clock speed dictates the number of instructions that can be run • per second The faster the clock speed the more instructions can be run per second •
5(c)(i) [2 marks]
1 mark per bullet point to max 2 Cloud storage can be free (for small quantities ) • No need for separate (high capacity) storage devices // saves storage on • existing devices Can access data from any computer with internet access • Most cloud data services will have in-built backup/disaster recovery • Security could be better • Can easily increase capacity • Data can be easily shared •
5(c)(ii) [4 marks]
1 mark per bullet point to max 2 : Can only access (the cloud) with internet access • Security may not be strong // no control over security • There may not be any backups // no control over backups • It can take a long time to upload/download the data • It can be more expensive in the long term • There could be a limit to the amount of storage unless paid for • There could be compatibility/access issues • There could be issues with the company offering cloud services •
5(d)
1 mark for each correct line
Melinda and her friends set up a peer-to-peer network between their computers to share data.
(a) Describe the key features of a peer-to-peer network. 2 marks
(b) Describe two drawbacks to Melinda and her friends of using a peer-to-peer network. 4 marks
1
2
(c) Melinda connects her laptop to the internet through her router. 2 marks
| (i) Tick (3) one box in each row to identify whether t not. | the task is perform | med by the router or |
|---|---|---|
| Task | Performed by router |
Not performed by router |
| Receives packets from devices | ||
| Finds the IP address of a Uniform Resource Locator (URL) | ||
| Directs each packet to all devices attached to it | ||
| Stores the IP and/or MAC address of all devices attached to it |
(ii) Melinda mainly uses the internet to watch films and play computer games. 3 marks
| Tick (3) one bo or wireless netw | ox to identify whe work and justify y |
|---|---|
| Wired | |
| Wireless |
Justification
(d) Melinda sends emails from her webmail account (email account accessed through a website). 3 marks
Explain whether Melinda is using the internet, or the World Wide Web (WWW), or both.
Show mark scheme
4(a) [2 marks]
1 mark per bullet point to max 2 All computers are of equal status • Each computer provides access to resources and data // data is • distributed Computers can communicate and share resources • Each computer is responsible for its own security •
4(b) [4 marks]
1 mark per bullet point to max 2 per drawback Reduced security // no central management of security • … only as secure as the weakest computer on the network • … each computer is at risk from viruses from other computers • No central management of backup • ... if the data from one computer is not backed up it is lost to all of them • No central management of files/software • … consistency may be difficult to maintain • … each computer may have different software from the others • Individual computers may respond slower • … because they are being accessed by other computers • In order to share files etc. all the computers involved need to be switched • on ... so the files etc. may not be always available •
4(c)(i) [2 marks]
1 mark for first 2 ticks, 1 mark for last 2 (shaded) Performed Not performed Task by router by router Receives packets from devices Finds the IP address of a Uniform Resource Locator (URL) Directs each packet to all devices attached to it Stores the IP and/or MAC address of all devices attached to it
4(c)(ii) [3 marks]
1 mark per bullet point for justification up to max 3 No mark for identification of wired/wireless Wired Faster connection // higher bandwidth • …. needed as she is downloading/streaming large files • … less time waiting / less latency / fewer delays • More reliable / stable connection • … is less susceptible to issues with distance/walls/interference • More secure • Wireless Freedom of movement • … can move between different rooms with a mobile device and still • receive/transmit data … no need of a physical connection • Easily expanded if friends want to access the same network • Less cabling / expertise is needed • ... making the initial setup less expensive •
4(d) [2 marks]
1 mark for identifying that she is using both. 1 mark per bullet point for justification using internet because sending data on the infrastructure • using WWW because accessing a website (that is stored on a web • server operated by the webmail) that is part of the WWW