Synchronization between LDP and IGP applies to MPLS networks where primary and backup LSPs exist. LSPs are established between LSRs based on IGP. When the LDP session on the primary LSP fails (not due to a link failure) or the faulty primary LSP is restored, you can enable synchronization between LDP and IGP to prevent traffic interruption caused by the active/standby switchover.
Before configuring synchronization between LDP and IGP, configure a local LDP session. For details, see Configuring Basic Functions of MPLS LDP.