D.L. Mills finite-state automaton with defined events, state transitions and actions. The following diagram shows a simplified graphical representation of this machine (see Section 3.4 for a detailed state transition table). +-------+ | |---------------+---------------+ +---->| Idle | A A | | |-----------+ | | | +-------+ | | | | | A Request | | Cease | Cease | Start | | Cease | | | | V | Refuse V | | | +-------+ Confirm +-------+ Up +-------+ | | |-------->| |-------->| | | | Aqsn | | Down | Down | Up | | | |----+ | | Exterior Gateway Protocol Formal Specification