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AS & A Level · AS/A Level

Computer Science

Networks and protocols

Name: ____________________Date: October 10, 2026
  1. 1.

    Distinguish a switch's typical role within a local network from a router's role between IP networks.

    [3 marks] · no calculator
  2. 2.

    Explain what DNS contributes when a browser connects to a named website, and why resolving a name does not itself download the web page.

    [3 marks] · no calculator
  3. 3.

    A 12 MB file crosses a 24 Mb s^-1 link. Use decimal units and ignore overhead. Calculate minimum transfer time and explain why real time may be longer.

    [3 marks]
  4. 4.

    A file has 5000 payload bytes; each packet can carry at most 1400 payload bytes and adds a 40-byte header. Calculate packet count and total transmitted bytes, with no padding or retransmission.

    [3 marks]
  5. 5.

    Packets arrive out of order and one is missing. Explain how a reliable ordered transport can deliver the correct byte stream, and why IP routing alone does not guarantee this.

    [4 marks] · no calculator
  6. 6.

    For live voice, evaluate using a low-overhead datagram transport instead of reliable ordered transport, considering late packets as well as lost packets.

    [4 marks] · no calculator

Original, unofficial practice questions from SubjectScout — not official past-paper questions.

Marking points are indicative, not an official mark scheme. Accept equivalent valid methods and supported interpretations that address the task; award each mark once without requiring the model wording.