The Goddard Mission Services Evolution Center (GMSEC) Message Bus is a robust, lightweight, fault-tolerant middleware implementation that supports all messaging capabilities of the GMSEC API, including publish/subscribe and request/reply. The Message Bus enables NASA to provide an open-source middleware solution, for no additional cost, that is self-configuring, easy to install, and can be used for the development of GMSEC-compliant components. Some professional capabilities provided by

this software include failover and fault tolerance, good performance, compression, debugging, and wide platform support.

This architecture is a distributed software system that routes messages based on message subject names and knowledge of the locations in the network of the interested software components. Functional software components register with the message bus, so that a location directory can be maintained. The functional applications then send messages onto the bus with an indication of the message type/subject/etc. Other applications that want to receive data register with the message bus and indicate what message types/subjects they want to receive. The message bus maintains a routing table where routes publish messages to the applications that have requested them. One message may be delivered to many different applications. Use of the message bus eliminates the need for each application to create separate communications paths with each application to which it interfaces.

The nature of the GMSEC Message Bus enables any project or user to quickly take the initial steps for creating or connecting GMSEC-compliant components, and for developing small systems without high license fees and learning curves. This software uses middleware to facilitate cross application or component communication on a software bus.

This work was done by Arturo Mayorga and John O. Bristow of Goddard Space Flight Center and Mike Butschky of Interface and Control Systems. For more information, download the Technical Support Package (free white paper) at under the Software category. GSC-15575-1

NASA Tech Briefs Magazine

This article first appeared in the January, 2011 issue of NASA Tech Briefs Magazine.

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