what is the exact difference between Closed and Stopped State in PPP State machine

Question

I wanted to know what is the exact difference between Closed and Stopped State in PPP State machine.

It would be great full if someone explain in detail.

I am designing ppp stack using C++.

Thanks a lot in advance.

Answer 1

If I remember right the difference is that the Closed state gets entered because of something like an administrative action (ie., the user is stopping PPP).

The stopped state occurs when the link is terminated by the other side.

RFC 1661 has the details, even if it's not the easiest read - just follow the state machines defined there and you should be OK.

Answer 2

"Closed" means the PPP state machine for that link, has been shut down (closed) through either some user intervention (link shutdown) or the underlying physical layer going down (alarm detection, etc).

"Stopped" means either 1) The PPP state machine did not succeed in the negotiation and hence stopped, and will retry after some time, or 2) The peer terminated the session, and the local side will re-initiate negotiation after some time.