Question

A network engineer is troubleshooting label allocation on an MPLS core running LDP. On a Cisco IOS XR router, the engineer observes that the same local label value is advertised to all LDP peers for a given IGP prefix, regardless of which interface the LDP session uses. A colleague expected each interface to allocate a distinct label for the prefix. Which statement correctly explains this behavior?

Accepted Answer

LDP uses per-platform label space by default, so a single label is allocated per prefix and shared across all interfaces and LDP sessions.

Answer

LDP uses per-interface label space by default, so the router is misconfigured and should assign unique labels per interface.

Answer

The behavior indicates LDP is operating in downstream-on-demand mode, which forces one label per platform.

Answer

The router has enabled independent label distribution control, which collapses all interface labels into a single value.