User equipment appends a header to a non-access stratum (NAS) message to form an encapsulated NAS message. The header is formed according to a wireline access network protocol. The user equipment transmits the encapsulated NAS message over a wireline connection between the user equipment and an interworking function of a core network. The interworking function receives the encapsulated NAS message over the wired connection and forwards the NAS message to a core network entity selected based on addressing information included in the header. A point-to-point control plane session can be established between the user equipment and the interworking function in response to a session request transmitted by the user equipment. The point-to-point control plane session can be used to convey encapsulated NAS messages, which can be used to request establishment of an NAS session for a user plane connection to the core network.