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OCR H446 1.3.3 Packet and circuit switching

Part 4 of 10 · H446 1.3.3 · Networks

Switching is easy to recite and harder to choose between, and that choice is where the H446 1.3.3 marks sit. This worksheet models packet and circuit switching side by side, then makes students recommend one for workloads whose constraints pull in different directions.

Students will:

  • describe how each method allocates a route and capacity
  • compare the two methods on failure response, ordering and use of available capacity
  • justify a switching choice from the constraint a scenario actually states
  • state the drawback accepted by each recommendation rather than presenting one method as always better

Inside: 5 explanation cells, 1 multiple-choice question, 2 fill-in-the-blanks cells and 2 written answers. 24 marks, about 35 to 45 minutes.

Series: H446 1.3.3 · Networks, part 4 of 10.

Shared by Coding PathwayVerified teacher

  • 10 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 31 Aug 2026
  • Updated 3 Sept 2026

Preview

The whole resource, exactly as a class sees it. Answers and marking are held back.

Packet and circuit switching

Both methods move data between endpoints, but they allocate routes and capacity differently. A good recommendation begins with the scenario's constraint, not an absolute rule.

Compare states, not slogans

Circuit switching and packet switching comparedCircuit switchingone route and capacity established firstpredictable resource; unused capacity can be wastedPacket switchingP1P3P2P4numbered packets may take available routesshared capacity; variable delay/order; resilient reroutingChoose from the scenario constraint, not from an absolute rule that one method is always better.

Circuit switching establishes a dedicated end-to-end circuit and reserves capacity for the session. This can give predictable capacity/delay, but setup is required and reserved capacity may sit unused.

Packet switching divides data into addressed packets that share network links and may take different routes. It can use capacity efficiently and reroute around failure, but delay/order can vary and packets need reconstruction.

Worked recommendation

A remote-control link requires stable, predictable capacity continuously for ten minutes, and the organisation can afford reserved capacity. A circuit is defensible because dedicated resources meet the stated predictability need.

A public information service sends bursts to thousands of users over resilient shared infrastructure. Packet switching is defensible because traffic can share capacity and packets can be rerouted. Neither conclusion follows from ‘voice versus data’ alone.

Multiple choice1 mark

Which feature belongs to packet switching?

  • ACapacity is reserved on one end-to-end circuit before every session
  • BAll data must arrive in order because the route is fixed
  • CNo control information is needed
  • DIndependently addressed packets may take different available routes
Fill in the blanks4 marks
Circuit switching establishes a gap 1 route and reserves gap 2. Packet switching divides data into gap 3 that share links and may arrive out of gap 4.
  • dedicated
  • capacity
  • packets
  • order
  • DNS
Written answer6 marks

Compare packet and circuit switching using three matched criteria: route/capacity, failure response and delay/utilisation.

For each criterion, state both sides and the consequence. Avoid three isolated advantages.

Students type their answer here.

Apply the model independently

The remaining tasks change the context or reduce the support. Complete them without copying the worked model, then check that each explanation connects a mechanism to its consequence.

Written answer9 marks

Recommend packet or circuit switching for each: (1) intermittent environmental readings across a network with occasional link failures; (2) a paid control channel requiring reserved, predictable capacity for a fixed session; (3) a school file-download service with bursty demand. Justify each from at least two constraints.

Feature → scenario effect → judgement. A qualified alternative can earn credit when fully reasoned.

Students type their answer here.

Fill in the blanks4 marks
A circuit reserves an end-to-end checkpoint gap 1. Packet switching shares network checkpoint gap 2. Packets may be checkpoint gap 3 at the receiver. A recommendation must follow the scenario checkpoint gap 4.

Review your understanding

Before submitting, check that you can explain the main distinction in your own words, apply it in an unfamiliar context and justify each consequence rather than only naming a feature.