Quick Answer

The answer is that the LFIB is populated with the best label bindings as the final step in the MPLS LDP label distribution and FIB population order. This sequence is correct because IP routing and IGP convergence must occur first to establish reachability, followed by LDP neighbor discovery and session formation. Only then can LDP assign local labels to FECs and advertise them, with remote labels received and stored in the LIB. The LFIB is populated last because it requires the best label bindings—selected from the LIB based on the IP routing table—to be installed for actual packet forwarding. On the ENCOR 350-401 exam, this drag-and-drop task tests your understanding of the control plane versus data plane separation: a common trap is placing LFIB population before label advertisement, but remember that the LFIB is a forwarding table, not a learning table. A useful memory tip is "RIP L-LFIB"—Routing converges, Interfaces form LDP, Labels assigned, Learned remote labels, then Fill the LFIB.