Networking Basics · 11
🔌 Network Media
What physically carries your data — cables, fiber, and radio waves⏱ ~2 min
🏗️Media is the road your data drives on
Just as goods travel by truck (road), train (rail), or plane (air), data travels through different physical media. Each has trade-offs: trucks are flexible but slow; planes are fast but expensive. Copper cable, fiber optic, and wireless each have their own speed, distance, and cost profile — network engineers pick the right one for each job.
The Three Types of Network Media
🟤 Copper (Twisted Pair)
- •Data travels as electrical pulses
- •Most common — used in Ethernet (Cat5e, Cat6, Cat6A)
- •Max speed: 10 Gbps (Cat6A)
- •Max distance: ~100 meters per segment
- •Vulnerable to electromagnetic interference (EMI)
- •Cheap and easy to terminate
- •Used for: office LANs, home networks
💡 Fiber Optic
- •Data travels as pulses of light through glass or plastic
- •Single-mode: long distances (100+ km), used by ISPs
- •Multi-mode: shorter distances, used in data centers
- •Immune to EMI — perfect for industrial environments
- •Much harder to tap than copper — any light leakage degrades signal and can trigger alerts
- •Expensive to install; connectors require precision
- •Used for: ISP backbone, data centers, campus networks
Wireless — the invisible medium
- •Data travels as electromagnetic waves (radio frequencies) through air
- •WiFi (802.11) — most common; 2.4 GHz and 5 GHz bands
- •Cellular (4G LTE / 5G) — provided by mobile carriers; 5G reaches speeds over 1 Gbps
- •Bluetooth — short range (~10m), low power; connects peripherals (headphones, keyboards)
- •Satellite — for remote areas with no cables; high latency due to signal traveling 35,000 km to orbit
- •No physical security — signals travel in all directions and can be intercepted
| Media | Speed | Distance | Cost | Interference Risk |
|---|---|---|---|---|
| Copper (Cat6) | Up to 10 Gbps | 100 m | Low | Moderate (EMI) |
| Fiber (single-mode) | 100+ Gbps | 100+ km | High | None |
| WiFi 6 (802.11ax) | Up to 9.6 Gbps | ~50 m | Medium | High (crowded spectrum) |
| 5G Cellular | Up to 10 Gbps | City-wide | Medium | Low |
| Satellite (LEO) | Up to 200 Mbps | Global | High | Weather affects signal |
★ FactFiber optic cables are so fast because light travels at ~200,000 km/s through glass — about 2/3 the speed of light in a vacuum. A single hair-thin glass fiber can carry over 100 terabits per second using different colors (wavelengths) of light simultaneously, a technique called WDM (Wavelength Division Multiplexing).
🔒 SecurityCopper cables can be tapped with inexpensive equipment — an attacker physically clips onto the cable and reads electrical signals. Fiber is significantly harder to tap: a technique called macrobending (bending the fiber to cause light leakage) can intercept signals, but it degrades signal strength and requires specialized equipment. This is why fiber is preferred over copper for high-security links, though no physical medium is completely tap-proof. Wireless is the most exposed — signals radiate in all directions, making passive eavesdropping possible from a parking lot with no physical access required.
🧠Quick Checkfirst try = +5 XP
A hospital needs to run a network connection 500 meters between two buildings. The cable will pass near high-powered medical imaging machines (MRI) that generate strong electromagnetic fields. Which media type should they use?
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