The Link Control Protocol (LCP) is used to establish the connection through an exchange of configure packets. This exchange is complete, and the LCP opened state entered, once a Configure-Ack packet has been both sent and received.
LCP allows for the negotiation of multiple options in a PPP session. MP is somewhat different from PPP, and therefore the following options are set for MP and are not negotiated:
no async control character map
no magic number
no link quality monitoring
address and control field compression
protocol field compression
no compound frames
no self-describing padding
Any non-LCP packets received during this phase must be silently discarded.