
Refer to the exhibit. An engineering team must update the network configuration so that data traffic from router A to router D continues in case of a network outage between routers B and C. During a recent outage on the B-C link, the IGP traffic path was switched to the alternate path via routers E and F. but label forwarding did not occur on the new path. Which action ensures that traffic on the end-to-end path continues?
Correct Answer: D
Enabling MPLS LDP IGP Synchronization ensures that the IGP advertises a route only if there is a corresponding label binding from LDP. This synchronization helps prevent blackholing traffic when there is a direct link failure in the network. When the B-C link failed, the IGP could find an alternate path via routers E and F, but without LDP synchronization, the labels for MPLS were not available on this new path, leading to traffic loss. By enabling LDP IGP Synchronization, routers will only use paths for which a complete set of labels exists, ensuring label forwarding occurs on the alternate path.
The information provided is based on the Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) course materials, which cover the configuration, verification, troubleshooting, and optimization of Service Provider IP network infrastructures, including MPLS LDP IGP Synchronization