This is to announce what we believe is the first ROS2 RMW implementation that is not based on RTPS or DDS, you can find it here https://github.com/ros2/rmw_dps It runs over Intel’s Distributed Pub/Sub protocol for IoT (imaginatively named DPS-for-IoT) https://github.com/intel/dps-for-iot Full documentation for the DPS protocol and APIs is here https://intel.github.io/dps-for-iot
The base protocol is largely complete but we are working on some QoS features needed by ROS2. The package has been tested on Bouncy on Ubuntu 18.04 and Windows 10. Most of the ROS2 test cases are currently passing. The RMW implementation uses CBOR for payload serialization and the DPS API has a handy JSON translator. Without saying if this is a good or bad thing, this makes is easy to send or receive ROS2 messages without actually running any ROS2 code.
We welcome community participation and contributions to either the RMW or DPS code bases.