QoS includes dependable timeliness, availability/reliability, data
quality, etc. In order to achieve the JBI promise of getting the Right
Information to the Right People at the Right Time, QoS must be
addressed over the full life cycle of JBI information objects, from
"discription and discovery" to "delivery and error recovery".  


DDS also has implications for other battlefield communications equipment, shipboard networks and avionics, as well as for medical or industrial automation systems. 


The distribution of real-time data is becoming paramount for what the
military calls "threat assessment," as is the need to alert military
units from different countries of impending threats. Hence, a standard
like DDS could make "a significant difference," said Michael Rogosin,
general manager for European, Middle Eastern and African markets at
Real-Time Innovations (RTI).  


In a typical scenario, a data set collected by a ship-based radar
indicating a threat may need to be communicated to a different data
set detected by avionics radar. Without standardized middleware in
place, it's unlikely the two sets of intelligence picked up by
individual software applications could be fused for real-time
analysis, Rogosin said.  


The issue of real-time data distribution and communication gets more
complicated when multinational forces operate together. Until now,
there has been no global middleware that would make defense
electronics systems and applications interoperable. "The
military/aerospace market takes the Object Management Group very
seriously. They will adopt the standard very vigorously," predicted
Bruce Ericson, RTI's marketing vice president.  


The Corba standard is designed for client-server communications that
distributes objects. But there has been no standard for a
"data-centric real-time system" that needs a major amount of data
distribution, according to RTI. Instead of a model in which the client
initiates communications and invokes the server operations to change
or access information, many in the industry believe a
publish-subscribe model offers a better mechanism for moving lots of
data between applications.  


Publish-subscribe systems, which connect anonymous information
producers (publishers) with information consumers (subscribers), are
well suited for developing fault-tolerant systems, proponents
said. The distributed application is composed of processes, each
running in a separate address space, often on different
computers. Each process may simultaneously publish and subscribe to
distributed information.