Internet and Its Uses · 4 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 7% of your exam marks.
Network topologies, protocols (HTTP, TCP/IP, FTP, DNS) and network hardware appear consistently.
A protocol is a set of rules that govern how devices on a network communicate with each other.
Without a protocol, two computers could send data but neither would understand what the other was sending. Protocols define the format of packets, the order of messages, error handling, and many other details.
The CIE syllabus names a small set of protocols you should know.
TCP/IP is the foundational protocol suite of the internet. TCP splits data into packets and reassembles them; IP routes the packets between networks.
Almost every other internet protocol (HTTP, HTTPS, FTP, SMTP) runs on top of TCP/IP.
HTTP (Hypertext Transfer Protocol) is the protocol used by web browsers to request web pages from web servers and receive the response.
GET request) and how the server replies (with the HTML content).HTTPS (Hypertext Transfer Protocol Secure) is HTTP with encryption added on top, using TLS/SSL.
The lock icon in the browser's address bar indicates HTTPS is in use.
FTP is a protocol used for transferring files between a client and a server over a network.
POP3 and IMAP are protocols used by email clients to receive messages from an email server.
SMTP is the protocol used to send emails from a client to a server, and between mail servers.
POP3/IMAP pull emails down; SMTP pushes them out. The pair work together to deliver a message from sender to recipient.
| Protocol | Used for |
|---|---|
| TCP/IP | The core transport and addressing layer that everything else runs on |
| HTTP | Web browsing (unencrypted) |
| HTTPS | Web browsing with encryption |
| FTP | File transfer between client and server |
| SMTP | Sending email |
| POP3 | Retrieving email (older, downloads and deletes from server) |
| IMAP | Retrieving email (modern, keeps emails on server) |
Protocols are what make the internet work as one giant network rather than many incompatible private systems. A web browser written in California can read a website hosted in Singapore because both ends speak the same HTTPS/TCP/IP protocols. The two sides do not need to know anything about each other except that they both follow the same agreed rules.