In the process of configuring, maintaining and terminating the point-to-point link, the PPP link goes through several distinct phases which are specified in the following simplified state diagram:
+------+ +-----------+ +--------------+ | | UP | | OPENED | | SUCCESS/NONE | Dead |------->| Establish |---------->| Authenticate |--+ | | | | | | | +------+ +-----------+ +--------------+ | ^ | | | | FAIL | FAIL | | +<--------------+ +----------+ | | | | | +-----------+ | +---------+ | | DOWN | | | CLOSING | | | +------------| Terminate |<---+<----------| Network |<-+ | | | | +-----------+ +---------+
Not all transitions are specified in this diagram. The following semantics MUST be followed.