LDP-IGP synchronization is implemented to suppress IGP convergence until LDP is converged. After a fault occurs over the active link, LDP-IGP synchronization keeps forwarding traffic over the backup link LSP until the new LSP is set up on the active link. When the LDP converged, the backup link LSP is deleted. This is required as IPv4 traffic or VPN traffic are commonly recursively lookup and iterated into MPLS LSP based on BGP next hop information. If the IGP converged too early and send the traffic to active link over naked IP, intermediate router may not have the route entry/label to perform forwarding causing the traffic to drop at the intermediate router. We deploy IGP-IDP synchronization feature in ATN side