Common protocols including TCP/IP (Transmission Control Protocol/Internet…

The idea

A protocol is a set of rules for how devices exchange data. TCP/IP is the core suite: IP addresses and routes packets between networks, while TCP splits data into segments, numbers them and reassembles them, requesting retransmission of lost segments. HTTP transfers web pages between a browser and a web server; HTTPS does the same but encrypts the traffic using TLS, protecting passwords and card details. FTP moves files between a client and a server, often for uploading website content. POP downloads email from a server to one device, typically removing it from the server. IMAP keeps email on the server and synchronises folders and read status across multiple devices. SMTP sends outgoing email from a client to a server and between servers. In the exam you may match a protocol to a task or explain the difference between two similar protocols.

What earns the marks

• TCP/IP is the foundational suite: IP handles addressing and routing, while TCP provides reliable, ordered delivery by segmenting data and checking for errors.
• HTTP is used by web browsers and servers to request and transfer web pages and other resources.
• HTTPS is HTTP carried over an encrypted connection, commonly using TLS, so data such as login details cannot easily be read in transit.
• FTP transfers files between a client and a server and is often used to upload or download website files.
• POP downloads email to a single device and may delete it from the server, whereas IMAP stores email on the server and synchronises it across devices.
• SMTP sends outgoing email from a client to a mail server and relays email between mail servers.

Common mistakes and how to put them right

• Swapping POP and IMAP.

  Put it right by remembering POP is a download-and-often-delete protocol for one device, while IMAP keeps messages on the server and synchronises multiple devices.

• Using SMTP to receive email.

  Put it right by stating that SMTP is for sending and relaying outgoing mail, while POP or IMAP is used to retrieve it.

• Saying HTTPS is just a faster HTTP.

  Put it right by explaining that HTTPS adds encryption and authentication, usually through TLS, rather than changing the speed.

Exam tips

• Match each protocol to a clear everyday action: browsing, secure browsing, file transfer, sending mail, downloading mail or synchronising mail.
• When comparing POP and IMAP, mention server storage and multi-device access explicitly.
• For TCP/IP, separate the roles of IP (addressing and routing) and TCP (reliable delivery) in your answer.