CoAP / RFC 7252

Overview

CoAP, defined in RFC 7252, is a lightweight RESTful protocol designed for constrained devices and low-power, lossy networks. It uses the same request methods as HTTP but runs over UDP, which makes it a common choice for sensor networks and IoT deployments where full HTTP is too heavy. Secure CoAP runs over DTLS. Tenders for sensor-heavy or IoT deployments often list CoAP among the required device protocols.

Key requirements

RESTful request methods

Support the request methods the protocol defines (GET, POST, PUT, DELETE) for resources on devices.

Constrained transport

Operate over UDP so it suits low-power, lossy networks and constrained hardware.

Client and server roles

Act as the requesting side and, where needed, the responding side.

Secure communication

Protect traffic with DTLS where confidentiality and authentication are required.

How ControlBird aligns

Client and server

ControlBird acts as a CoAP client to read and write resources on constrained devices, and as a CoAP server to expose its own data to other systems.

RESTful access over UDP

It uses the protocol’s standard request methods over UDP to communicate with sensors and constrained endpoints.

Secure CoAP over DTLS

Endpoints can enable DTLS so CoAP traffic is encrypted and authenticated rather than sent in the clear.

Mapped into the entity model

CoAP resources bind to entities and fields like the other protocols, so device data flows into the same store, history, alarms, and dashboards.