2.5. Transmission Media and Transceivers
đź’ˇ First Principle: All network communication ultimately travels over physical media. Copper carries electrical signals, fiber carries light pulses, and wireless uses radio waves. Each medium has trade-offs in distance, speed, cost, and interference resistance that determine where it's appropriate.
What breaks without media knowledge? Install Cat5e for a 10Gbps link—it won't work (Cat5e maxes at 1Gbps). Run single-mode fiber for a 50-meter data center connection—you've wasted money (multimode is cheaper for short distances). Deploy 2.4GHz wireless in a microwave-heavy cafeteria—constant interference.
Think of media like roads: copper is a city street (good for short trips, many intersections/interference potential), fiber is a highway (fast, long-distance, fewer interruptions), and wireless is air travel (no physical path needed, but affected by weather and obstacles).
