Communication protocols you should know

Protocols are the rules that let devices, apps, and services talk to each other. A clear protocol stack makes networks predictable, helpful for troubleshooting and design. Two main transport options exist: TCP and UDP. TCP provides reliability, ordering, and error checking. It resends lost data and ensures packets arrive in the right order. UDP is faster and lighter but does not guarantee delivery.

Common protocols you will encounter

  • HTTP/HTTPS: web traffic. HTTP runs on TCP; HTTPS adds TLS encryption.
  • DNS: translates domain names to addresses.
  • SMTP/IMAP/POP3: email transfer protocols.
  • FTP/SFTP: file transfer; SFTP runs over SSH.
  • MQTT: lightweight publish-subscribe protocol for IoT, usually over TCP with a broker.
  • CoAP: constrained devices, often over UDP.
  • WebSocket: real-time channels over TCP for live apps.
  • TLS/SSL: encryption for many protocols (HTTPS, mail, etc.).
  • Bluetooth and Wi‑Fi: local links; Bluetooth for close devices, Wi‑Fi for larger networks.
  • IPv4 and IPv6: address schemes; most networks run dual-stack with translation.

How to choose a protocol

Choosing the right protocol is about balance. If you need reliability and order, TCP-based protocols are safer. For low overhead and speed, UDP-based or lightweight options can work, but you must handle loss at the application layer. Security matters: prefer encrypted variants such as TLS-enabled connections and avoid sending sensitive data in the clear.

For scale and energy, MQTT shines in many-device IoT setups, while CoAP targets constrained sensors. In networks with variable conditions, consider protocols that tolerate loss but provide timely updates, and design app logic to cope with retries and buffering.

Examples help: a web page uses HTTPS over TCP to keep data private. A home sensor might publish updates via MQTT over TLS to a broker, then receive commands in real time. Real-time apps often use WebSocket over TCP for a persistent channel.

Understanding where a protocol fits in the OSI model helps when debugging. Most application protocols sit on top of TCP or UDP, which are transport-layer choices built on IP addressing.

Key Takeaways

  • TCP vs UDP: choose based on reliability needs and network conditions.
  • Security matters: enable encryption (TLS) for privacy and integrity.
  • Get familiar with core protocols (HTTP/HTTPS, DNS, MQTT, CoAP, SMTP, WebSocket) to design and troubleshoot networks.