Marianville · Grade 11 ICT
Unit 2 · Transmission Media · Chapter 6

Choosing the Right Medium

Week 2 · Day 3 · Benchmark 11.4.1.2 Compare guided and unguided transmission media
Essential question

How do we pick the best medium for a real situation?

Learning objectives
  • Weigh cost, distance, speed and reliability
  • Recommend a medium for three different PNG scenarios
  • Justify each recommendation

Overview

There is no single 'best' cable or wireless link — the right medium depends on distance, budget, speed needed and the environment. A good technician thinks about trade-offs, not favourites.

The four questions

Before choosing, ask: (1) How far does the signal have to travel? (2) How much bandwidth do users need? (3) How much money is available? (4) Is the environment noisy, wet, or hard to reach with cable? The answers point to one or two sensible options.

Three PNG scenarios

A 40-PC school lab in Port Moresby: UTP Cat 6 to each desk, one fibre backbone to the server room. An island health clinic: VSAT for internet + local Wi-Fi for staff. An ISP backbone from Lae to Madang: long-haul single-mode fibre, with microwave as a backup path.

Hybrid is normal

Real networks mix media. Fibre backbone, copper to desks, Wi-Fi for phones. Understanding when to switch from one to the other is what makes a network designer useful.

Activity

Recommend a Medium

  1. Working in groups, take one scenario: (a) 4-PC teachers' room, (b) 100-PC secondary school lab, (c) village aid post 30 km from the nearest tower.
  2. Choose one or more media and justify with cost, distance, speed, environment.
  3. Present to the class and defend your choice.
Review questions
  1. Give one reason to prefer fibre over UTP for a backbone.
    Reveal answer

    Longer distance and higher bandwidth without interference.

  2. When is VSAT the sensible choice?
    Reveal answer

    When no cable or mobile tower reaches the site.

  3. What is a hybrid network?
    Reveal answer

    A network that combines two or more transmission media.

Take it home

Design the network for your dream classroom on paper: mark each cable type and every wireless link.

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