OSI Model

OSI Layer 1 Unwrapped! The Physical Layer

4:59Coming soon

A user's computer is slow after an office move. The settings are perfect, the link light is green — and nothing in software will ever fix it, because the problem is in the road. In this episode Professor Flows takes you down to Layer 1 of the OSI model, the Physical layer, using Byte City's three kinds of road: asphalt (copper), the glass express tube (fiber) and the radio tower (wireless).

You'll learn

What Layer 1 actually does — and why it never reads what it carries
Twisted pair: why the twist matters, the 100-metre limit, Cat 5e vs Cat 6 vs Cat 6A
Fiber: multimode vs single-mode, and why light ignores electrical noise
Wireless: shared air, distance, and 2.4 vs 5 and 6 GHz
What lives at Layer 1: cables, connectors, transceivers, repeaters and hubs
The four ways Layer 1 breaks: attenuation, interference, crosstalk and damage
A real fix: reading link speed with Get-NetAdapter and finding a broken pair

Chapters

0:00The slow desk
0:30Layer 1 has one job: move bits
0:56Road 1: copper and twisted pair
1:47Road 2: fiber
2:17Road 3: wireless
2:44What lives at Layer 1 — and how it breaks
3:29The real thing: Get-NetAdapter and the broken pair
4:10Exam corner
4:28Recap and next time

Exam objectives: CompTIA Network+ N10-009: 1.1 (OSI model), 1.5 (transmission media and transceivers), 5.2 (cable and physical interface issues).

Byte City is not affiliated with or endorsed by CompTIA.