Communication Protocols in the Internet of Systems

The Internet of Systems (IoS) connects sensors, machines, software, and services across many networks. Teams blend IT and OT, spread across sites and clouds, and expect data to move reliably. Good protocols reduce ambiguity, lower power use, and help systems scale without chaos.

In IoS, a layered view helps. The network layer uses IP, the transport layer uses TCP or UDP, and the application layer defines message formats. Because many devices are small or battery-powered, lightweight protocols are common. Popular choices include MQTT for publish/subscribe, CoAP for simple requests, AMQP for enterprise messaging, DDS for real-time data, and OPC UA for industrial interoperability.

Security and reliability cannot be afterthoughts. Use TLS or DTLS to protect data in transit, and strong authentication to verify identities. Plan for outages with durable sessions and sensible quality of service. Edge gateways often translate between protocols, letting old equipment talk to modern cloud services without replacing hardware.

Interoperability comes from standard models and compact data encoding. OPC UA offers a shared information model, while MQTT favors small, efficient payloads and CoAP supports CBOR or JSON. The best mix depends on latency, bandwidth, and safety needs. For tight real-time control, DDS or OPC UA TSN can be suitable; for simple telemetry, MQTT over TLS often works well.

Example in a smart factory: sensors publish temperature via MQTT to an edge broker. A gateway translates data for the control system through OPC UA, and streams it to an analytics service via DDS. A cloud app then consumes the data securely from the DDS stream.

Tip for practitioners: map device capabilities to protocol features, keep messages compact, and test end-to-end security. Document why each choice was made so future teams can maintain the system.

Key Takeaways

  • Choose protocol features based on data needs and latency.
  • Use gateways to bridge old and new systems.
  • Start security early and keep it manageable.