Communications technology
Learn the core concepts and decision-making in Cambridge 9626 Topic 14, then practise recall, application and transfer with fictional scenarios.
Section 14 · Communications technology
Exam scope and assessment notes
This is original StudyForA teaching and fictional practice based on Cambridge syllabus outcomes, not copied syllabus text, an official question, a required software brand or a Cambridge mark scheme. Practical software tasks here are planning and reasoning exercises; StudyForA does not inspect files created in spreadsheet, database, graphics, audio/video or animation software, simulate the practical exam environment, award official marks or predict a grade. Follow the software and file-format requirements issued by your centre for your exam year.
Before you begin
- Check whether your route is AS Level (Topics 1–11) or full A Level (Topics 1–21).
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Before Topic 14: communications technology
What you will learn
- Compare LAN, WAN, client-server, peer-to-peer, VPN and mobile networks; topologies, architecture and uses
- Explain NICs/WNICs, repeaters, hubs, switches, access points, gateways, bridges and routers
- Compare file/web/mail/application/print/FTP/proxy/virtual servers and server farms; explain cloud computing
- Compare media, bandwidth, bit rates, streaming, protocols, TCP/IP and OSI layers, routing, firewalls, wireless/mobile/satellite systems and disaster recovery
Networks connect devices and services
A LAN covers a limited site; a WAN connects sites over larger distances. Client-server centralises services; peer-to-peer shares directly. A VPN creates a protected tunnel over another network. NICs connect devices; switches forward within a LAN; routers connect networks; access points provide wireless access; gateways connect unlike systems. Servers provide file, web, mail, application, print, FTP or proxy services; virtual servers share physical capacity.
Capacity, protocols and resilience shape the experience
Bandwidth is a capacity measure; bit rate is the data transmitted per second. Streaming quality depends on source bit rate, available bandwidth and delay. Fibre, copper, wireless, lasers and mobile/satellite links differ in speed, reach, interference and cost. Protocols define communication; TCP supports reliable delivery, IP addresses/routes packets, and layered models divide responsibilities. Firewalls control access. Disaster recovery plans identify threats, protect backups and test recovery.
Sources for this lesson
Pause and explain
Which approach best demonstrates secure, reliable IT practice in communications technology?
Worked example
A school needs shared files, secure access from home and video lessons. Recommend a basic architecture and identify one bottleneck risk.
Show the worked solution
- Use a client-server LAN for managed shared files and access controls.
- Provide a VPN or secure cloud service for remote access.
- Check upload capacity and concurrent streaming demand.
Answer A client-server LAN with managed file and authentication services supports school controls. Remote staff can use a properly secured VPN, or an appropriately governed cloud service. Video lessons may saturate the school's uplink, so measure peak concurrent bandwidth and quality of service. Backups, tested recovery and firewall rules should protect availability and access.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A branch office is connected to headquarters using a VPN over the internet. Explain what the VPN does and what it does not guarantee.
Give me a hint
Describe the protected tunnel and the remaining endpoint/network risks.
Compare my reasoning
- Identify the public internet as the underlying network.
- Explain tunnelling and encryption/authentication at a high level.
- Name compromised endpoints or misconfiguration as residual risks.
A VPN establishes an authenticated, protected tunnel between endpoints over the internet, helping keep traffic confidential in transit. It does not guarantee that a compromised laptop, weak password, unsafe local network or misconfigured VPN is secure. Endpoint protection and access controls are still required.
Look for these in your work
- Explains the tunnel
- States scope
- Names residual risks
A live lesson uses 4 Mbit/s per learner and 180 learners watch at once. Estimate required downstream capacity before overhead and explain one practical margin.
Give me a hint
Multiply the per-stream bit rate by concurrent streams.
Compare my reasoning
- Convert 4 Mbit/s × 180 streams.
- State the theoretical aggregate.
- Allow headroom for protocol overhead and other traffic.
The streams need 720 Mbit/s in aggregate before overhead. The school should allow additional capacity for protocol overhead, other network use and bursts, and measure actual peak conditions. Adaptive streaming or a content-delivery service may reduce origin-server load but does not eliminate the school's access-link constraint.
Look for these in your work
- Calculates the aggregate
- States the assumption
- Adds realistic network headroom
A small company loses access to its server after a power failure. What should a disaster-recovery plan specify and test?
Give me a hint
Include threats, recovery order, backups, people and a timed exercise.
Compare my reasoning
- Identify likely threats and critical services.
- Define backup, recovery priority, roles and target times.
- Run restoration exercises and record gaps.
The plan should identify power/equipment and other threats, prioritise critical services, name responsible people, define alternate power or service arrangements, and specify backup locations and recovery steps. Test restoring data and operating the service within realistic targets, then update the plan from failures found. A backup that has never been restored is unverified.
Look for these in your work
- Covers people and process
- Includes protected backups
- Requires practical testing
Common mistakes
- Treating bandwidth and bit rate as identical
- Saying a VPN makes every endpoint secure
- Assuming cloud computing removes provider or outage risks
What can you explain now?
A branch office is connected to headquarters using a VPN over the internet. Explain what the VPN does and what it does not guarantee.
Compare with the explanation
A VPN establishes an authenticated, protected tunnel between endpoints over the internet, helping keep traffic confidential in transit. It does not guarantee that a compromised laptop, weak password, unsafe local network or misconfigured VPN is secure. Endpoint protection and access controls are still required.
Describe the protected tunnel and the remaining endpoint/network risks.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
What does a network protocol specify, and why do layered models help?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.