A protocol is a set of rules that defines how data is transmitted and received across a network. Protocols ensure that devices from different manufacturers can communicate correctly. Without protocols, computers would not know how to format, address, or interpret network messages.
TCP/IP (Transmission Control Protocol / Internet Protocol) is the fundamental suite of protocols used on the internet and most networks.
Reliable, connection-oriented protocol.
Before data is sent, a connection is established (3-way handshake).
Data is split into packets; each packet is acknowledged by the receiver.
If a packet is lost or corrupted, it is re-sent.
Packets are reassembled in the correct order.
Used for: web browsing, email, file downloads — where accuracy matters.
Faster but unreliable protocol.
No connection established before sending.
No acknowledgements — sender doesn't know if data arrived.
Lost packets are not re-sent.
Lower overhead = lower latency.
Used for: live video streaming, online gaming, VoIP — where speed matters more than perfection.
IP (Internet Protocol) handles the addressing and routing of packets. Every device on the internet has an IP address. IP decides which route packets take through the network.
| Protocol | Full name | Used for | Port |
|---|---|---|---|
| HTTP | HyperText Transfer Protocol | Requesting and receiving web pages (not secure — data is unencrypted) | 80 |
| HTTPS | HTTP Secure | Secure web browsing; uses TLS/SSL encryption; padlock in browser; banking, shopping | 443 |
| FTP | File Transfer Protocol | Uploading and downloading files between computers; used by web developers to upload website files to a server | 21 |
| SMTP | Simple Mail Transfer Protocol | Sending email from a client to a server, or between mail servers | 25/587 |
| IMAP | Internet Message Access Protocol | Reading email stored on a server; emails stay on the server (accessible from multiple devices) | 143/993 |
| POP3 | Post Office Protocol v3 | Downloads email from server to local device; email removed from server; older protocol | 110/995 |
The DNS is like the internet's phone book. It translates human-readable domain names (e.g. www.google.com) into IP addresses (e.g. 142.250.185.46) that computers can use to locate the server.
Without DNS, you would have to type in IP addresses to visit every website. DNS servers are maintained globally and are organised in a hierarchy.
| Feature | HTTP | HTTPS |
|---|---|---|
| Encryption | None — data sent in plaintext | TLS/SSL encryption — data is scrambled |
| Security | Data can be intercepted (man-in-the-middle attack) | Data cannot be read if intercepted |
| Padlock in browser | No | Yes 🔒 |
| Port | 80 | 443 |
| Used for | Non-sensitive websites | Banking, shopping, login pages — all modern sites |
8 questions · 22 marks
| Term | Definition |
|---|
Timed exam conditions.