Networking From the Ground Up

Lesson Promise

By the end of this lesson, you will understand what a network is, how IP addresses and ports identify endpoints, how data is packaged into packets, and how the network stack's layers work together to deliver data from one machine to another.

Narration Draft

Part 1 — What Is a Network? (3:00) A network connects computers so they can exchange data. Explain IP addresses (like street addresses), ports (like apartment numbers), and packets (like envelopes). Show how a web request is split into many packets.

Part 2 — The Client-Server Model (3:00) The client asks, the server responds. Explain the request-response cycle, sockets, and stateful vs stateless servers. Why most services centralize in servers rather than using peer-to-peer.

Part 3 — Network Layers (5:00) The five-layer model: Application (HTTP), Transport (TCP), Network (IP), Link (Ethernet), Physical (cable/radio). Each layer adds a header (encapsulation). Trace a packet through all five layers — what each header contains and what each layer contributes.

Part 4 — TCP vs UDP (4:00) TCP: connection-oriented, reliable, ordered. UDP: connectionless, best-effort, fast. When to use each. The three-way handshake for TCP.

Visual Sequence

1. Computers connected by roads — analogy for a network
2. IP address as street address, port as apartment number
3. Data split into packets with headers and sequence numbers
4. Five-layer encapsulation diagram: HTTP → TCP segment → IP packet → Ethernet frame → bits
5. TCP three-way handshake animation
6. TCP reliability: sequence numbers, ACKs, retransmission

Companion Material

• Article: What Is a Network?
• Article: The Client-Server Model
• Diagram: Network Layers in a Request
• Trace: Packet Through Network Layers
• Practice: Calculate Network Latency
• Interview: TCP vs UDP