OpenDDS
OpenDDS is open source publish/subscribe middleware
OpenDDS is an open source implementation of the Object Management Group (OMG) Data Distribution Service (DDS), providing a publish/subscribe middleware solution for real-time distributed systems. OpenDDS includes development and run-time tools.
Full product information, source code, documentation, build instructions, and license information are available from http://www.opendds.org.
Commercial consulting, support, and training for OpenDDS are available. OpenDDS is in production use today...