What Is Computer Networking
A
computer network
is a system where computers exchange data via communication protocols.
The
Internet
is the largest network, composed of many interconnected networks using the
TCP/IP protocol suite
.
The 5-Layer Network Model
From bottom to top:
Physical Layer
– Transmits raw bits via media (cables, fiber, Wi-Fi)
Data Link Layer
– Provides reliable local transmission (MAC addressing, Ethernet)
Network Layer
– Handles routing and addressing across networks (IP, ICMP)
Transport Layer
– Ensures end-to-end communication (TCP, UDP)
Application Layer
– Supports user-facing protocols (HTTP, FTP, WebSocket)
Key Protocols:
Application Layer: HTTP, WebSocket
Transport Layer: TCP vs UDP
Network Layer: IP, DNS
HTTP: The Foundation of the Web
HTTP vs HTTPS
Feature
HTTP
HTTPS
Encryption
No (plain text)
Yes (via TLS/SSL)
Default Port
80
443
Security
Vulnerable to attacks
Protects against MITM, sniffing
Full Process: How a Browser Loads a Page
User enters
https://google.com
Browser uses DNS to resolve domain to an IP address