PetriCode examples -- Simple Framing Protocol (SFP): The model
The model for the Simple Framing Protocol, as all PetriCode models, is hierarchical with three distinct layers. The top layer (Protocol) is the Protocol Layer which defines the principal agents and the channels between them. The second layer, which includes the pages Sender and Receiver is the protocol layer where the interface and life cycle of each of the principle agents is defined. The final layer is the service layer where the life-cycle of each of the services are defined.
The Protocol Layer
The protocol level consists of the two principal agents of the SFP: The Sender and the Receiver. In additions there is, a channel between the two principals. The two principals are represented by substitution transitions annotated with <<principal()>> which indicates to the generator that the referenced pages are indeed principals agents of the protocol.