Network Control Protocol

The Network Control Protocol is part of the [Point-to-Point Protocol]

NCP requires to establish the link first, after the link is established and authentication (if any) is successful, the connection goes to the networking state. In this state, PPP uses another protocol called Network Control Protocol (NCP). NCP is a set of control protocols to allow the encapsulation of data coming from network layer protocols into PPP frame.PPP requires two parties to negotiate not only at the data link layer, but also at the network layer. Before user data can be sent, a connection must be established at this level. The set of packets that establish and terminate a network layer connection for IP packets is called IP control protocol (IPCP).

<Internet Architecture and Protocols> by Behroz