Achieving interoperability using CoAP

Application-layer interoperability using CoAP can be achieved by the introduction of three technologies: CoRE, LWM2M, and IPSO Smart Objects.

Discovering resources using CoRE

We've already mentioned CoRE in the previous chapter. The CoAP protocol is an artefact published by the IETF CoRE Working Group. Another artefact is the CoRE Link Format, which we've used to find what resources are available on a device. By performing a GET method call on the /.well-known/core resource, the caller will receive a Link Format document, briefly describing what resources are available on the device, and some minimal set of corresponding information, such as if the resource is observable or not.

The following is an example Link Format document, generated by our SensorCoap application developed in the previous chapter. New lines have been added for readability. Resources are separated by commas (,), and parameters for each resource are separated by semicolons (;). The obs...