Unit 3.1

The Internet: Technology Background

IT 204: E-Commerce

Learning Objectives

By the end of this chapter, you will be able to:

✅ Define the core technologies that underpin the Internet.
✅ Explain the process of packet switching and its role in data transmission.
✅ Differentiate between the functions of TCP and IP in the TCP/IP protocol suite.
✅ Describe the client/server computing model.
✅ Analyze the context of Internet adoption in Nepal.

What is the Internet? 🌐

Definition: A global network of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide.

Think of it as a "network of networks" connecting:

🏢 Private & Business Networks
🏛️ Government Networks
🎓 Academic Networks
🏠 Public Networks

🕰️ Timeline: How the Internet Was Built

1969: ARPANET links its first computers (UCLA → Stanford Research Institute). The first message, "LO", crashes after two letters.
1974: Vint Cerf and Bob Kahn publish the design that becomes TCP/IP.
1 January 1983: "Flag day": ARPANET switches fully to TCP/IP. Many call this the birth of the modern Internet.
1989–1991: Tim Berners-Lee at CERN invents the World Wide Web, which runs on top of the Internet.
1995: The US backbone (NSFNET) is retired; the Internet becomes commercial, and e-commerce follows.

The Internet came first; the Web and e-commerce were built on it two decades later.

🎬 Watch: September 1969 at UCLA

The Foundation: Packet Switching

Instead of a dedicated connection, the Internet breaks data down into small pieces called packets.

Anatomy of a Packet 📦

Header

Destination Address (IP)
Source Address
Packet Number

Payload

The actual data chunk
(e.g., part of an image, email text)

These packets travel independently across the network and are reassembled at the destination.

📞 Circuit Switching vs 📦 Packet Switching

      📞 Circuit switching (old phone network)
      A dedicated path is reserved for the whole call.
The line sits idle during silences, and nobody else can use it.
If one link breaks, the call drops.

    

      📦 Packet switching (Internet)
      No reserved path; links are shared by everyone's packets.
Capacity is used only when data is actually sent.
If one link breaks, routers send packets another way.

    

Why it suits e-commerce: millions of short, bursty requests (a page view, a cart click) share the same network cheaply.

How Packet Switching Works ⚡

1. Slicing: A large file (e.g., a photo) is broken into small, numbered packets.
2. Addressing: Each packet's header is stamped with the destination IP address.
3. Routing: Packets are sent onto the network, taking different paths to the destination.
4. Reassembly: The destination computer collects all packets and reassembles them in the correct order.

This method is efficient and robust. If one path is congested, packets can find another way.

🎬 Watch: Your Data, in Parcels

🧮 Worked Example: Uploading a Product Photo

A seller uploads a 3 MB product photo. Each packet carries about 1,500 bytes, of which about 1,460 is data (example figures).

3 MB ≈ 3,000,000 bytes ÷ 1,460 ≈ 2,055 packets.
Each packet gets a header: source IP, destination IP, sequence number.
Packet #17 goes via Mumbai, packet #18 via Delhi. They can arrive out of order.
3 packets are lost on the way. TCP notices the gaps in the numbers and asks for only those 3 again, not the whole photo.

Numbering + resending only what's missing is what makes a "best effort" network reliable.

💳 Card Processing Flow Simulator

🛒 Customer

→

🏪 Merchant

→

🔒 Gateway

→

🏦 Acquiring Bank

→

💳 Card Network

→

🏛️ Issuing Bank

Click "Process Payment" to simulate a card transaction.

Log will appear here...

🇳🇵 Context: NPR 4,500 card payment at Daraz.com.np using a NIC Asia Visa card.

The Language of the Internet: TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is the fundamental communication protocol suite of the Internet.

It's not one protocol, but two main ones working together:

TCP: The "Manager"
IP: The "Postal Service"

TCP vs. IP: A Team Effort 🤝

TCP (Transmission Control Protocol)

🎯 The Reliability Manager

Breaks data into packets before sending.
Numbers the packets for reordering.
Checks that all packets have arrived.
Reassembles packets at the destination.

IP (Internet Protocol)

🗺️ The Address & Routing System

Responsible for addressing each packet with source & destination.
Routes the packets from one network to another.
It's the "best effort" delivery service.

🧱 The Four Layers of the TCP/IP Model

Layer	Job	Example protocols
4. Application	What the user's software speaks	HTTP/HTTPS, SMTP, DNS
3. Transport	Reliable delivery, ordering, resending	TCP, UDP
2. Internet	Addressing and routing packets	IP (IPv4, IPv6)
1. Network Interface	Putting bits on the physical medium	Ethernet, Wi-Fi, 4G/5G, fibre

Each layer only talks to the one above and below, so Wi-Fi can change to fibre without changing your browser.

🔢 IPv4 vs IPv6: Running Out of Addresses

IPv4 (1981)

32-bit address, e.g. 192.168.1.10

2³² ≈ 4.3 billion addresses

IPv6 (1998)

128-bit address, e.g. 2001:db8::1

2¹²⁸ ≈ 3.4 × 10³⁸ addresses

In February 2011, IANA handed out the last free blocks of IPv4 addresses to the regional registries.
With more phones than people on Earth, IPv4 can't give every device its own address, so ISPs share addresses (NAT) while moving to IPv6.

🔐 Security: 3D Secure Authentication Demo

🛒 Checkout — Daraz.com.np

Order: Sony Headphones — NPR 8,999

3DS Auth Steps

1. Merchant collects card data
2. Send to 3DS server for enrollment
3. Bank sends OTP to your phone
4. You enter OTP (challenge)
5. Bank verifies & authorizes

🇳🇵 NIC Asia & Global IME require 3DS OTP for all online card transactions.

The Dominant Structure: Client/Server Computing

Client/Server Model: A distributed structure that separates tasks between service providers (servers) and service requesters (clients).

🔍 Client

Requests information or services.
Examples: Your web browser, email app, a mobile game.

🗄️ Server

Provides the requested data or service.
Examples: Web server (hosting a site), mail server, database server.

Client/Server in Action: Visiting a Website

Client Request: Your browser (the client) sends a request for `google.com` to a DNS server.
IP Address: The DNS server returns the IP address for Google's server.
TCP/IP in Motion: Your browser sends an HTTP request packet (via TCP/IP) to that IP address.
Server Response: Google's web server (the server) receives the request and sends the website data back in packets.
Display: Your browser (client) reassembles the packets and renders the webpage.

🎬 Watch: Finding the Server

🙋 Quick Activity: Where Do Your Packets Go?

Lecturer demo (or try at home): on Windows type tracert google.com, on Mac/Linux traceroute google.com.

Each line is one router hop. Count them.

Guess first: how many hops from Kathmandu to Google? Under 5? 5–15? Over 15?

Every hop is a router reading the IP header and passing the packet on: IP at work, live.

Case Study: The Internet in Nepal 🇳🇵

The core technologies are global, but local context shapes adoption.

Challenges

💰 Cost: Still relatively high for a significant portion of the population.
🔌 Infrastructure: Underdeveloped in some rural/remote areas, leading to slower speeds.
📖 Digital Literacy: A barrier for some to fully utilize Internet resources.

Opportunities

🧑‍💻 Youth Population: Large, growing, and eager to adopt new technology.
🏛️ Government Support: Actively working to improve national infrastructure.
📈 Business Adoption: More businesses are using the internet for e-commerce and operations.

Nepal Telecom Tower

🇳🇵 Nepal Payment Methods Explorer (1/2)

Click a payment method above to explore it.

🇳🇵 Nepal Payment Methods Explorer (2/2)

Click a payment method above to explore it.

Nepal's Internet Market Landscape 📊

Several key players drive connectivity in the country:

Nepal Telecom

The state-owned incumbent, providing a wide range of services including mobile and fixed-line internet.

Ncell

A major private mobile network operator, a key driver of mobile broadband access across the nation.

WorldLink

One of the largest private Internet Service Providers (ISPs), especially dominant in the fiber-to-the-home (FTTH) market.

Key Point: The competition between these players is helping to drive down costs and improve service quality, accelerating internet adoption for e-commerce.

📊 BNPL Calculator — Buy Now, Pay Later

Product Price

NPR 10,000

Repayment Period

Interest Type

💰 Payment Breakdown

Product Price:NPR 10,000

Monthly Payment:NPR 3,333

Total Interest:NPR 0

Total Cost:NPR 10,000

🇳🇵 Khalti BNPL: 0% interest for 3 months on select merchants. Great for planned purchases!

Key Takeaways

A quick review of today's core concepts:

Packet Switching: The foundational method of breaking data into packets for efficient and robust transmission over shared networks.
TCP/IP: The two-part protocol suite that runs the Internet. TCP manages reliable data transfer, while IP handles addressing and routing.
Client/Server Model: The primary architecture of the web, where clients (like your browser) request resources from powerful, centralized servers.
Local Context Matters: Global technologies are shaped by local factors like infrastructure, cost, and policy, as seen in the case of Nepal.

💬 Think, Pair, Share (3 minutes)

1. A video call drops for half a second, but a file download never loses a byte. Which protocol behaviour explains the difference?

2. If ARPANET had used circuit switching, could an online shop serve 10,000 customers at once? Why or why not?

3. Your phone and your laptop at home show the same public IP address. How is that possible?

🧠 Payment Method Match Quiz

Question 1 of 5

Exam Practice 📝

Short answer

What is packet switching?
List the four layers of the TCP/IP model.
Distinguish between IPv4 and IPv6.

Exam Practice 📝 (continued)

Long answer

Explain the key technology concepts behind the Internet: packet switching, TCP/IP, and client/server computing.
Compare circuit switching and packet switching, and explain why packet switching suits e-commerce.

Revise the answers in the full note.

Image & Video Credits

Images

Internet map: The Opte Project, CC BY 2.5 (Wikimedia Commons)
BBN IMP: Don DeBold, CC BY 2.0 (Wikimedia Commons)
Vint Cerf: Veni Markovski, CC BY 3.0 (Wikimedia Commons)
IBM server rack: Jemimus, CC BY 2.0 (Wikimedia Commons)
Nepal Telecom tower: Janak Bhatta, CC BY 4.0 (Wikimedia Commons)

Videos (YouTube)

Your Data, in Parcels (11–100 s)
September 1969 at UCLA (22–95 s)
Finding the Server (74–127 s)

Thank You

Any questions?

Next Up: Unit 3.2 - Internet Infrastructure & The Web

Course Home | Unit 3 Overview

📖 Read the full note

Unit 3.1: The Internet: Technology Background