Unit 3.2
The Infrastructure of the Internet
IT 204: E-Commerce
Learning Objectives 🎯
By the end of this chapter, you will be able to:
- ✅ Describe the internet backbone.
- ✅ Explain the role of an Internet Service Provider (ISP).
- ✅ Identify TCP/IP as the core protocol of the internet.
A Global Network of Networks
The internet isn't a single entity. It's a vast, interconnected system of smaller networks operating on a global scale.
Think of it as a hierarchy, from massive global highways down to the street you live on.
The Internet's Hierarchical Structure
Tier 1: The Backbone
🌍 Global high-speed fiber-optic networks.
Tier 2: ISPs
🏢 Regional & local providers connecting to the backbone.
Tier 3: End Users
🏠 You, your home, your business.
Layer 1: The Internet Backbone 🌐
Definition: A network of very high-speed fiber-optic cables that span the globe, both overland and undersea.
- ⚡ Capable of transmitting terabits of data per second.
- 🔗 Undersea cables connect continents, forming the physical basis for global communication.
- 🏢 Owned and operated by a small number of large telecommunication companies (Tier 1 Providers).
Discussion Point: Who Owns the Internet?
This is a common question! The answer is complex.
Answer: No single person or entity owns the internet. However, a handful of large companies (Tier 1 providers like AT&T, Lumen, Orange) own and operate the physical backbone infrastructure.
They "peer" with each other to exchange traffic without cost, forming the core of the global network.
Layer 2: Internet Service Providers (ISPs)
Definition: Companies that provide individuals and businesses with access to the internet.
ISPs act as the "on-ramp" to the internet highway.
- They purchase high-speed connectivity from backbone providers.
- They then sell this access in smaller packages to their customers.
Practical Application: ISPs in Nepal 🇳🇵
How does Nepal connect to the global internet?
Major ISPs:
- WorldLink
- Vianet
- Nepal Telecom (NTC)
- Classic Tech
Global Connectivity:
Nepalese ISPs connect to the global backbone primarily through terrestrial fiber-optic links via India (e.g., to Mumbai) and China.
This makes our internet access dependent on the infrastructure and policies of our neighbors.
Analogy: The Internet Highway System 🚗
Let's make this easier to understand:
- The Backbone is like the national highway system (e.g., Prithvi Highway) – massive, high-speed, long-distance.
- ISPs are the city and town roads that connect to the main highways.
- Your Home Network is your personal driveway, giving you access to the local roads.
The Protocol: TCP/IP 📜
How does all this complex hardware work together seamlessly?
TCP/IP (Transmission Control Protocol/Internet Protocol) is the fundamental suite of communication protocols that governs the entire system.
It's the universal language and rulebook of the internet.
How TCP/IP Works (A Simple View)
It ensures your data gets from A to B reliably.
- Packetizing: TCP breaks your data (e.g., an email) into small pieces called packets.
- Addressing: IP adds an address to each packet, like putting a letter in a stamped envelope.
- Routing: Routers across the internet read the addresses and forward the packets towards their destination.
- Reassembly: TCP at the destination reassembles the packets in the correct order and checks for errors.
This process allows for efficient, fault-tolerant data transmission across a complex global network.
Key Takeaways 🔍
Three core components make up the internet's infrastructure:
- The Backbone: A global network of high-speed fiber-optic cables forms the core.
- ISPs: They provide the crucial link between the backbone and end-users like us.
- TCP/IP: The protocol suite that provides the rules, ensuring reliable communication across the entire network.