An emergency-management office relies on the MPLS underlay to forward labeled unicast traffic across the county core. What is LDP’s primary role in that design?
Select an answer to reveal the explanation.
Short Explanation
LDP is the label mailman for the underlay. Wherever the IGP knows a prefix, LDP hands out a transport label so P and PE routers can build LSPs. It isn’t the RT factory and it isn’t IPsec.
Full Explanation
Label Distribution Protocol advertises bindings between underlay FEC prefixes—typically those learned via the IGP—and local labels, enabling unicast transport LSPs across the MPLS core. Route targets are MP-BGP VPN constructs, encryption is orthogonal, and NHRP belongs to DMVPN. Understanding LDP’s transport-label role is foundational before blaming VPN signaling for underlay LSP breaks.