Networking

Route How to forward packets though internet or intranet

Switch Layer 2 process in OSI model

WLAN Wireless Local Area Network

What is Networking?

Networking refers to the practice of interconnecting computing devices to share resources, exchange data, and communicate seamlessly. It encompasses hardware, software, protocols, and infrastructure enabling devices (like computers, servers, smartphones, IoT gadgets) to “talk” to each other locally or globally.

Core Goals of Networking

1. Resource Sharing: Access printers, storage, or applications across devices.
2. Communication: Enable email, messaging, video calls, and collaboration tools.
3. Data Exchange: Transfer files, databases, or real-time information (e.g., stock prices).
4. Remote Access: Control devices or services from anywhere (e.g., cloud servers).
5. Centralized Management: Administer users, security, and updates efficiently (e.g., Active Directory).

Key Components

Component	Role
Hardware	Routers, switches, access points, firewalls, cables, network cards.
Software	Operating systems, protocols (TCP/IP), applications (web browsers, VPN clients).
Media	Wired (Ethernet, fiber optic) or wireless (Wi-Fi, cellular, Bluetooth).
Protocols	Rules governing data transmission (TCP, UDP, IP, HTTP, DNS, DHCP).
Topology	Layout of devices (star, mesh, bus, ring).

Types of Networks

Type	Scope	Example
PAN (Personal)	10 meters	Bluetooth headset + phone.
LAN (Local)	Building/campus	Office Wi-Fi, home network.
WAN (Wide)	Cities/countries	Internet, corporate network branches.
MAN (Metropolitan)	City-wide	ISP infrastructure in a metro area.
VPN (Virtual)	Secure overlay network	Remote access to company resources.

How Networking Works: The OSI Model

A 7-layer framework standardizing communication:

1. Physical (Layer 1): Electrical signals, cables, Wi-Fi radio waves.
2. Data Link (Layer 2): MAC addresses, switches, error detection (Ethernet).
3. Network (Layer 3): IP addresses, routing (routers, IP).
4. Transport (Layer 4): Reliable data delivery (TCP/UDP, ports).
5. Session (Layer 5): Establishes/manages connections.
6. Presentation (Layer 6): Data formatting (encryption, compression).
7. Application (Layer 7): User-facing apps (HTTP, FTP, SMTP).

🔑 Simplified Analogy:
Sending a letter:

• Application: Writing the content.
• Transport: Putting it in an envelope (TCP = tracked mail; UDP = postcard).
• Network: Adding destination/sender addresses (IP).
• Data Link: Postal carrier routing between stations (MAC/switches).
• Physical: Delivery truck (cables/Wi-Fi).

Critical Protocols

• TCP/IP: Foundation of the internet (reliable, connection-oriented).
• UDP: Fast but unreliable (used for video streaming, gaming).
• HTTP/HTTPS: Web browsing.
• DNS: Translates google.com → 172.217.0.142.
• DHCP: Automatically assigns IP addresses to devices.
• BGP: Routes traffic between ISPs on the internet.

Why Networking Matters

• Internet Access: Global connectivity.
• Business Operations: Cloud services, remote work, e-commerce.
• Emerging Tech: IoT (smart homes), 5G, edge computing.
• Security: Firewalls, intrusion detection, VPNs protect data.
• Scalability: From small homes to hyperscale data centers.

Networking vs. Internet

• Networking: Broader concept (any device interconnection).
• Internet: A global WAN connecting millions of networks using TCP/IP.

Fun Fact:

The internet handles ~350 billion emails and ~5 billion Google searches daily. Over 95% of web servers run on Linux-powered networking infrastructure!

In essence: Networking is the digital nervous system of modern life — invisible yet essential for everything from streaming cat videos to running global finance.