Start with the recap, study the fully worked examples, then use the practice problems to
check your understanding of Internet.
This page combines explanation, solved examples, and follow-up practice so you can move
from recognition to confident problem-solving in CS Thinking.
Concept Recap
A global network of interconnected computer networks that communicate using standardized protocols (TCP/IP). The internet is decentralized—no single authority controls it. It connects billions of devices worldwide by routing data as packets through a shared infrastructure of cables, routers, and wireless links.
The internet is the world's biggest network — it connects smaller networks together so any device can talk to any other device, anywhere.
Read the first worked example with the solution open so the structure is clear.
Try the practice problems before revealing each solution.
Use the related concepts and background knowledge badges if you feel stuck.
What to Focus On
Core idea:The internet is decentralized — no single authority controls it. It works because everyone agrees on the same protocols.
Common stuck point:The internet is not the same as the World Wide Web. The web is one service that runs on the internet (alongside email, streaming, etc.).
Sense of Study hint:When understanding the internet, trace the path of data: your device sends a request through your router, to your ISP, across backbone networks, to the destination server. The response travels back the same way. Protocols like TCP/IP ensure the data arrives correctly.
Worked Examples
Example 1
easy
What is the difference between the internet and the World Wide Web (WWW)?
Answer
The internet is the physical network infrastructure. The WWW is a service running on it (web pages via HTTP). Email, streaming, and gaming also use the internet.
First step
1
Step 1: The internet is the global network of interconnected computers and cables — the physical infrastructure that carries data.
Full solution
2
Step 2: The World Wide Web is a service that runs on the internet — it consists of web pages, websites, and links accessed through browsers using HTTP/HTTPS.
3
Step 3: Other services also run on the internet: email (SMTP), file transfer (FTP), video streaming, online gaming. The web is just one (very popular) use of the internet.
Many people use 'internet' and 'web' interchangeably, but they are different things. The internet is the infrastructure; the web is one of many applications built on top of it.
Example 2
medium
Describe what happens step by step when you type 'www.example.com' into a web browser and press Enter.What happens step by step when you type a URL and press Enter?
Example 3
medium
A packet has 5 hops to its destination. Each hop adds 10 ms. What is the minimum total latency just from hops?Each of the 5 hops adds 10 ms. What is the total minimum latency?
Example 4
hard
A 100 MB file is sent over a 10 Mbps link with no overhead. How many seconds does the transfer take?
Practice Problems
Try these problems on your own first, then open the solution to compare your method.
Example 1
medium
Explain what an IP address is and why DNS is needed. What would browsing the web be like without DNS?
Example 2
hard
Explain why the internet is described as a 'network of networks'. How does this decentralised structure make it resilient?The internet is a network of networks. Why does this make it resilient?
Example 3
easy
The internet and the World Wide Web are the same thing. True or false?
Example 4
easy
Which protocol family lets the internet route data between networks?
Example 5
easy
Is the internet controlled by a single central authority? Yes or no.
Example 6
easy
Does data on the internet usually travel directly from sender to receiver? Yes or no.
Example 7
easy
Browsing a website is using which: the internet, the Web, or both?
Example 8
easy
What makes billions of different devices able to communicate on the internet?
Example 9
easy
Sending an email and loading a webpage both use the internet but different ____.
Example 10
easy
Email is part of the World Wide Web. True or false?
Example 11
medium
Why does the internet keep working even if some routers fail?
Example 12
medium
A friend says 'the Web went down so the internet is gone.' Correct the statement precisely.
Example 13
medium
Data from your computer to a server passes through 4 routers on the way. How many hops (links traversed) is that, counting start-to-router-1 ... router-4-to-server?Data passes through 4 routers. Count the links (hops).
Example 14
medium
Which is infrastructure and which is a service: (a) TCP/IP routing of packets, (b) a website you visit?
Example 15
medium
Why is no single company able to 'turn off' the entire internet?
Example 16
medium
Your home internet works but one specific website is unreachable while others load. Internet down, or that site's server down?
Example 17
medium
Put in order from most general to most specific: World Wide Web, internet, a single web page.
Example 18
medium
Data passes through 6 routers from your phone to a server. How many links does it traverse?Data from phone to server passes through 6 routers. Count all links.
Example 19
medium
A site loads for everyone else but not for you, on every device in your home. Internet-wide outage, or your home connection?
Example 20
challenge
Explain how packet switching plus decentralization together make the internet fault-tolerant.
Example 21
challenge
A student claims 'I downloaded an app, so I used the Web.' When is this wrong?
Example 22
challenge
Why can two people in different countries on different ISPs still load the same website?
Example 23
easy
Name the protocol used to load most modern web pages securely.
Example 24
easy
What does DNS stand for?
Example 25
easy
Which is hardware: a router or HTTP?
Example 26
easy
Name one service that uses the internet but is not the World Wide Web.
Example 27
easy
Who manages your home internet connection physically?
Example 28
medium
DNS resolves www.example.com to 93.184.216.34. What two things has DNS told the browser?DNS resolves www.example.com to 93.184.216.34. What two things has DNS told the browser?
Example 29
medium
Why is the internet considered 'best-effort' delivery?
Example 30
medium
Why is decentralization a security feature of the internet?
Example 31
medium
What does TCP add on top of IP?
Example 32
medium
Why does the internet need standardized protocols?
Example 33
medium
What does ISP stand for and what role does it play?
Example 34
medium
A user pings a server and gets 40 ms round-trip. What is the approximate one-way latency, assuming symmetric paths?Round-trip time = 40 ms. What is the approximate one-way latency?
Example 35
hard
Explain why caching DNS answers locally speeds up web browsing.
Example 36
hard
Why does IPv6 exist alongside IPv4?
Example 37
hard
A CDN places copies of a website's content in many cities. How does this improve speed for users?A CDN places content closer to users. How does this improve speed?
Example 38
hard
What is net neutrality, in one sentence?
Example 39
hard
Why are passwords sent over HTTP (not HTTPS) dangerous?
Example 40
hard
Why do internet outages sometimes only affect one country or region?A cable between N. America and Europe fails. Why do outages sometimes stay regional?
Example 41
challenge
Explain how BGP (Border Gateway Protocol) makes the internet 'a network of networks' work in practice.BGP lets independent networks (autonomous systems) advertise reachability to each other.
Example 42
challenge
Why is the 'end-to-end principle' considered foundational to the internet's design?