For computers to exchange data reliably, they follow agreed sets of rules called protocols. On top of those, the Internet offers many services — the web, email, chat, online banking and more. This chapter maps out the protocols you should know and the services they make possible.
1Internet protocols
A protocol is a set of rules that lets devices communicate. The key Internet protocols for your syllabus:
| Protocol | Full form | Used for |
|---|---|---|
| TCP/IP | Transmission Control Protocol / Internet Protocol | The core suite: splits data into packets, addresses them and reassembles them reliably |
| HTTP | HyperText Transfer Protocol | Transferring web pages between server and browser |
| HTTPS | HTTP Secure | Same as HTTP but encrypted (secure) — used for logins, payments |
| SMTP | Simple Mail Transfer Protocol | Sending email |
| POP3 | Post Office Protocol v3 | Receiving (downloading) email to your device |
- A protocol is a set of rules for communication; TCP/IP is the core suite that packetises and reliably delivers data.
- HTTP transfers web pages; HTTPS is the encrypted, secure version (used for logins and payments).
- SMTP sends email; POP3 receives/downloads email to your device.
2Remote login & file-transfer protocols
These protocols let you work on, or move files to/from, a computer somewhere else:
| Protocol | Purpose | Secure? |
|---|---|---|
| TELNET | Log in to and control a remote computer (old) | No (plain text) |
| SSH (Secure Shell) | Securely log in to and control a remote computer | Yes (encrypted) |
| FTP (File Transfer Protocol) | Upload/download files to/from a server | No |
| SFTP (SSH File Transfer Protocol) | Transfer files securely over SSH | Yes |
| SCP (Secure Copy Protocol) | Copy files securely between computers | Yes |
- TELNET and SSH let you log in to a remote computer; SSH is the secure (encrypted) one.
- FTP transfers files to/from a server; SFTP and SCP do it securely.
- Secure protocols encrypt data in transit so passwords and files can't be intercepted.
3Web services and e-services
Web services are the everyday things people do directly on the web:
- Chat — real-time text conversation (e.g. messaging apps).
- Email — sending and receiving electronic mail.
- Video conferencing — live audio/video meetings between people in different places.
E-services
E-services ("electronic services") are real-world activities delivered online:
| E-service | What it lets you do |
|---|---|
| e-Learning | Study courses online (like Vidaara) |
| e-Banking | Manage money and pay bills online |
| e-Shopping | Buy goods online |
| e-Reservation | Book tickets/seats (trains, flights, movies) |
| e-Governance | Use government services online (forms, taxes) |
| e-Groups | Online communities/mailing lists around a shared interest |
- Web services include chat, email and video conferencing.
- E-services deliver real-world tasks online: e-Learning, e-Banking, e-Shopping, e-Reservation, e-Governance, e-Groups.
- All of these run over Internet protocols like HTTP(S) and SMTP.
4Social networking and mobile technologies
Social networking platforms let people create profiles and connect, share posts, photos and videos, and message each other (e.g. Facebook, Instagram, X, LinkedIn). They are built on web and e-group ideas at a huge scale.
Mobile messaging
- SMS (Short Message Service) — short text-only messages (up to ~160 characters).
- MMS (Multimedia Messaging Service) — messages that can include pictures, audio and video.
Mobile network generations
| Generation | Brings |
|---|---|
| 3G | Mobile Internet, basic video calls |
| 4G | Fast Internet, smooth HD video streaming |
| 5G | Very high speed and very low delay (latency) — supports IoT, smart devices |
- Social networking platforms let people connect, share and message at large scale.
- SMS sends short text only; MMS can include pictures, audio and video.
- 3G→4G→5G are successive generations of mobile networks, each faster with lower delay.
★ Practical: match the protocol to the task
For each everyday action, name the protocol or service involved:
- Opening a shopping website that shows a padlock in the address bar.
- Your phone's mail app sending a message you wrote.
- Securely copying a project file to a school server.
- Sending a photo to a friend over your mobile network (not the Internet).
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