  Due to the advancement of computing and communication technology, networked
control systems may soon become prevalent in many control applications. While
the capability of employing the communication network in the control loop
certainly provides many benefits, it also raises several challenges which need
to be overcome to utilize the benefits.
  In this chapter, we focus on one major challenge: a middleware framework that
enables a networked control system to be implemented. Indeed our thesis is that
a middleware for networked control sys important for the future of networked
control systems.
  We discuss the fundamental issues which need to be considered in the design
and development of an appropriate middleware for networked control systems. We
describe \emph{Etherware}, a middleware for networked control system which has
been developed at the University of Illinois, as an example of such a
middleware framework, to illustrate how these issues can be addressed in the
design of a middleware. Using a networked inverted pendulum control system as
an example, we demonstrate the powerful capabilities provided by Etherware for
a networked control system.
