Saw a post on Hacker News discussing messaging. A comment mentioned Californium. Being the messaging nerd that I am, had to chase the reference. Little did I know there was a whole IETF protocol for machine to machine messaging on resource constrained devices, CoAP:
The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained networks in the Internet of Things. The protocol is designed for machine-to-machine (M2M) applications such as smart energy and building automation.
According to the IETF RFC (7252), CoAP has the following main features:
Web protocol fulfilling M2M requirements in constrained environments
UDP [RFC0768] binding with optional reliability supporting unicast and multicast requests.
Asynchronous message exchanges.
Low header overhead and parsing complexity.
URI and Content-type support.
Simple proxy and caching capabilities.
A stateless HTTP mapping, allowing proxies to be built providing access to CoAP resources via HTTP in a uniform way or for HTTP simple interfaces to be realized alternatively over CoAP.
Security binding to Datagram Transport Layer Security (DTLS) [RFC6347].
HTTPish packets over UDP with optional reliable transport.
Wonder if anybody uses CoAP in practice?