APC service provides a clean separation of the data paths from the control paths by encapsulating the data path creation and instantiation process. An operator is a unit of computation on some data. Only based on these attributes, is automatic composition of services possible. Communication using multicast is one way to deal with this. Each connector is characterized by a specific transport protocol.
Logical path is defined to be an ordered sequence of operators.
Each operator has an XML description associated with it, describing its attributes such as input type, output type, communication protocols supported. More importantly, each operator has various cost metrics associated with it. Users provide the goals for the optimization process. Depending on the applications, these goals can vary. Logical path creation process should return a list of possible paths, ordered by the decreasing cost based on the user's input parameters for optimization.