Figure 1 illustrates how the Ambient Network control space incorporates
the bearer and flow connectivity abstractions. The control
space encompasses the middle two layers in the figure. The con-trol space exposes the bearer abstraction to applications through
the Ambient Service Interface (ASI), its “upper” interface. It uses
the flow abstraction to control the connectivity plane functions regardless
of the underlying network technology; the “bottom” Ambient
Resource Interface (ARI) provides the flow abstraction.