The user can enable LDP FECs over IGP shortcuts by configuring T-LDP sessions to the destination of the RSVP LSP. In this case, LDP FEC is tunneled over the RSVP LSP, effectively implementing LDP-over-RSVP without having to enable the ldp-over-rsvp option in OSPF or IS-IS. The ldp-over-rsvp and igp-shortcut options are mutually exclusive under OSPF or IS-IS.