A session management function (SMF) sends, to a network repository function (NRF), a discovery request for at least one user plane function (UPF) that supports a layer 2 tunneling protocol (L2TP) tunnel. The SMF receives, from the NRF, a discovery response comprising an identity of a UPF that supports the L2TP tunnel. The SMF selects, based on the UPF supporting the L2TP tunnel, the UPF. The SMF sends, to the UPF, a session request message comprising tunnel information of the L2TP tunnel.