Microsoft Certified Systems Engineer (MCSE) Question:

Point to Point protocol helps communication between 2 computers over a serial cable, phone line or other fiber optic lines. E.g. Connection between an Internet Service Provider and a host. PPP also provides authentication. PPP operates by sending Request packets and waiting for Acknowledge packets that accept, reject or try to change the request.

The protocol is also used to negotiate on network address or compression options between the nodes. PPP has a number of phases as below:

* Link dead: - takes place when the connection fails.
* Link Establishment Phase: - Used to establish connection. If authentication is desired, it moves to next phase.
* Authentication Phase: - Allows the nodes to authenticate each other.
* Network-Layer Protocol Phase: - here, the network control protocols come into play. Data transport, closing of the protocols takes place in this phase.
* Link Termination Phase: - here, the connection is terminated.