Knowledge Organiser: Network Protocols
Key Terms
- Protocol: A set of agreed rules for how data is transmitted between devices
- HTTP: HyperText Transfer Protocol — transfers web pages (not secure)
- HTTPS: HTTP Secure — encrypted web pages
- FTP (OCR and Edexcel): File Transfer Protocol — transfers files between computers
- SMTP: Simple Mail Transfer Protocol — sends emails
- POP3 (Edexcel; OCR names POP): Post Office Protocol — downloads emails from server to device
- IMAP: Internet Message Access Protocol — syncs emails, keeps on server
Must-Know Facts
- HTTP is insecure, plain text; HTTPS is encrypted
- HTTPS must be used for banking, shopping, any sensitive data
- SMTP sends emails; POP3/IMAP receive emails
- POP3: downloads then deletes from server; IMAP: keeps emails on server, syncs all devices
- FTP transfers files but sends data and passwords in plain text
- Without HTTPS, data is transmitted in plain text and can be intercepted
Key Concepts
- Why protocols are needed: Devices from different manufacturers must agree on rules to communicate
- Why HTTPS uses encryption: Encryption scrambles data so it cannot be read if intercepted
- SMTP vs POP3/IMAP: SMTP is for sending only; POP3/IMAP are for receiving only
- POP3 vs IMAP: POP3 downloads to one device; IMAP syncs across multiple devices
Common Mistakes
- Saying SMTP is for receiving emails: SMTP is for sending emails only — POP3 and IMAP are used to receive emails; mixing these up is a very common exam error
- Confusing HTTP and HTTPS: HTTP transmits data in plain text (insecure); HTTPS encrypts data — always use HTTPS for any site handling personal data or passwords
- Saying protocols are optional: Protocols are essential agreed rules — without them, devices from different manufacturers could not communicate at all
- Mixing up POP3 and IMAP: POP3 downloads emails to one device and deletes them from the server; IMAP keeps emails on the server and syncs across all devices — IMAP is preferred for multiple devices