点对点协议(PPP)是专为建立简单的连接或链接而设计的，例如在两个不同的对等方或客户端之间传输数据包。基本上提供有限状态自动化以达到“打开”状态并进入NLP阶段。
有限站自动机由事件，状态和动作组成。事件基本上是过渡状态的类别。这些事件导致链接状态发生变化，也称为状态转换或状态转换。状态转换也称为状态机对事件的反应。
基本上有两个重要事件，即OPEN和CLOSE。
OPEN事件通常导致控制协议尝试建立或建立连接，而CLOSE事件导致终止连接。
此CLOSE事件还使状态机无需执行任何操作即可保持在此关闭状态。因此，可以说状态转换可以使机器保持其当前或当前状态。建立，维护和处理连接或链接的实际细节非常复杂，因为在与某些事件进行交互时，可能会导致链接中共有10种不同状态之一。要显示在该特定连接上运行的PPP链路(LCP)和NCP的状态，我们可以使用以下命令：
PPP控制协议的不同状态如下：
| Different States | Description |
|---|---|
| Initial | This state is Startup state. During this state, no occurring of OPEN event takes place and hardware is DOWN i.e. lower layer is unavailable. Restart timer is also not running during this state. |
| Starting | This state is generally Open Counterpart to Initial state. During this state, OPEN event usually occurs and gets initiated but hardware is still DOWN i.e. lower layer is still not available. Restart timer is also not running during this state. |
| Stopped | This state is generally Open Counterpart to Closed state During this state, hardware is generally UP i.e. link is available and even DOWN or TIMEOUT event usually occurs. Restart timer is also not running during this state. |
| Closed | During this state, hardware is generally UP i.e. link is available but no occurring of OPEN event takes place. Restart timer is also not running during this state. |
| Stopping | This state is generally Open Counterpart to Closing state During this state, link might be OPEN and remote station generally tries to CLOSE connection or link. |
| Closing | During this state, link might be UP, and occurring of CLOSE event takes place that tries to close link or connection. An attempt is also made to terminate to end connection by sending Terminate-Request but terminate request has nor has been received yet. Restart timer also starts running during this state. |
| Request-Sent | During this state, Configure-Request for configuring connection is sent usually but Configure-Ack has not been received yet nor has been sent. Restart timer also starts running during this state. |
| Ack-Sent | During this state, configure request is received usually i.e. Configure-Request and acknowledge is sent i.e. Configure-Ack. |
| Ack-RCVD | During this state, configure request is sent usually i.e. Configure-Request and acknowledge is received i.e. Configure-Ack. |
| Opened | During this state, acknowledge has been sent or transmitted and received i.e. Configure-Ack. Restart timer is also not running during this state. |