Core MPLS

This section provides a detailed explanation of Label Distribution Protocol, commonly known as LDP, within the service provider core network. It focuses on how LDP is configured, verified, and troubleshot as the MPLS underlay used to forward customer Layer 2 VPN and Layer 3 VPN traffic. Throughout this section, learners will understand how LDP enables routers in the provider core to exchange MPLS labels and build label-switched paths across the network. These label-switched paths allow customer traffic to move efficiently through the MPLS backbone without the core routers needing to maintain detailed customer routing information. The training covers the practical steps required to configure LDP, confirm that label exchange is working correctly, and verify MPLS forwarding behavior across the service provider infrastructure. It also explains common troubleshooting methods for issues such as missing labels, broken neighbor relationships, incorrect forwarding paths, and VPN traffic reachability problems. By the end of this section, learners will have a stronger understanding of how LDP supports MPLS-based service provider networks and how it functions as a critical foundation for delivering reliable L2VPN and L3VPN services.