Key term
OCR GCSE Computer Science J277
Systems Architecture
Memory and Storage
Topic overviewRAM, ROM, cache and virtual memorySecondary storage: magnetic, optical and solid stateData units and storage capacity calculationsBinary, denary and hexadecimal conversionsBinary addition, overflow and binary shiftsCharacter sets, ASCII and UnicodeBitmap images, colour depth and resolutionSound sampling, sample rate and bit depthLossy and lossless compression
Computer Networks, Connections and Protocols
Network Security
Systems Software
Ethical, Legal, Cultural and Environmental Impacts of Digital Technology
Algorithms
Programming Fundamentals
Producing Robust Programs
Programming Languages and Integrated Development Environments
Computer Networks, Connections and Protocols
- 6 subtopics
- 18 things to know
- J277/01
What Computer Networks, Connections and Protocols covers
Computer Networks, Connections and Protocols is examined in J277/01, Computer systems. It covers LANs, WANs and network performance, client-server and peer-to-peer networks, network hardware, DNS, hosting and the cloud, star and mesh topologies, wired and wireless connections, IP and MAC addresses and protocols, standards and layers.
Where it is assessed
J277/01
Computer systems, 1 hour 30 minutes and 50% of the GCSE.
Check the OCR specification ↗The 6 subtopics
Each one has its own page.
- LANs, WANs and network performanceLANs and WANs, bandwidth, and how the number of devices, transmission media, distance and interference affect performance, with worked transfer-time and shared-bandwidth calculations.Open →
- Client-server and peer-to-peer networksServers and clients, web, file, print and mail servers, peer-to-peer networks, the advantages and disadvantages of each model, and choosing one for a home or a school.Open →
- Network hardware, DNS, hosting and the cloudNICs, switches, routers and wireless access points, transmission media, the internet, how DNS turns a URL into an IP address, web hosting, and the cloud.Open →
- Star and mesh topologiesStar and mesh topologies, what happens when a cable or switch fails, full and partial mesh, wireless mesh networks, and choosing a topology for an office or hospital.Open →
- Wired and wireless connections, IP and MAC addressesEthernet, Wi-Fi and Bluetooth, wired against wireless connections, encryption on wireless networks, IPv4 and IPv6 addresses, and how MAC addresses differ from IP addresses.Open →
- Protocols, standards and layersStandards and protocols, TCP and IP, HTTP and HTTPS, FTP, SMTP, POP and IMAP, choosing an email protocol, and why networking is organised into layers.Open →
What you need to know
Answer each one before you reveal it.
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What does a router do, and what does a home router connect together?
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Describe how DNS is used when a URL is typed into a web browser.
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What is a computer network?
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What is a network topology?
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What is Ethernet?
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What is a standard in computing?
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Define the term LAN.
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What is a server?
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Describe a star topology.
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What is Wi-Fi?
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Why are standards important to hardware and software manufacturers?
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Give two common examples of a LAN.
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What is a client?
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What is the job of a NIC?
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What happens in a star network if one device's cable breaks?
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What is Bluetooth mainly used for?
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What is a network protocol?
Take Computer Networks, Connections and Protocols further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
LAN vs WAN
LAN: a group of connected computers on one site, run by a single organisation. WAN: connected computers spread across cities or countries over leased links.
Router vs Switch
Router: a device that forwards packets between separate networks using IP addresses. Switch: a device that delivers data to the right machine inside one LAN using MAC addresses.
Client-server vs Peer-to-peer
Client-server: a model where central machines provide services that other machines request. Peer-to-peer: a model where every computer has equal status and shares its resources directly.
Questions from this topic
Each one with the model answer underneath.
- 1
What is a computer network?
Model answer
A computer network is two or more computers or devices linked so that they can exchange data. Linked devices can share resources such as files, printers and an internet connection.
- 2
Define the term LAN.
Model answer
A LAN (Local Area Network) connects devices within a small geographical area, such as one building or site. A LAN is usually owned and managed by a single organisation.
- 3
Give two common examples of a LAN.
Model answer
A school network linking the computers in its classrooms is a LAN. A home network connecting a laptop, a phone and a smart TV to one router is a LAN too.
- 4
What is a WAN?
Model answer
A WAN (Wide Area Network) connects devices or LANs across a large geographical area, such as between cities or countries. The internet is the largest example of a WAN.
- 5
Why does a WAN usually rely on infrastructure owned by other companies?
Model answer
A WAN covers distances too great for one organisation to cable itself. The organisation leases lines from telecommunications companies or uses satellite links instead.
- 6
Why would a bank with branches all over the country use a WAN?
Model answer
A WAN links every branch to the bank's central systems. Staff in any branch can then reach the same customer records and accounts.
What is inside Levo
Six ways to work the same material.
Computer Networks, Connections and Protocols revision questions
- What does Computer Networks, Connections and Protocols cover in OCR GCSE Computer Science?
- 6 subtopics: lans, wans and network performance, client-server and peer-to-peer networks, network hardware, dns, hosting and the cloud, star and mesh topologies, wired and wireless connections, ip and mac addresses and protocols, standards and layers. Each one has its own page with questions and model answers.
- How is Computer Networks, Connections and Protocols organised?
- By the OCR J277 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Computer Networks, Connections and Protocols, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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