An ISP that provides private network services across the country has recently migrated their infrastructure to support MPLS technology. A network engineer configured mpls ip on all routers and impleme

Cisco Express Forwarding (CEF) is a prerequisite for MPLS functionality but does not control which interfaces participate in LDP label exchange.

The `mpls ldp sync` command synchronizes LDP session establishment with IGP convergence to prevent blackholing, not to control which interfaces LDP is enabled on.

RSVP-TE is a label distribution protocol used primarily for MPLS Traffic Engineering, not for automatically enabling LDP on IGP-associated interfaces.

The `mpls ldp autoconfig` command automatically enables LDP on interfaces that are participating in an IGP routing process, such as OSPF, and are also configured for MPLS IP forwarding. This directly achieves the goal of associating LDP label exchange with the active IGP instance on an interface, ensuring labels are distributed only where IGP routes are learned and MPLS is intended to run.