MPLS mandatory use of CEF

MPLS uses various data structures to function, including a Forwarding Information Base (FIB). For Cisco router configured with MPLS, the FIB is the CEF table. CEF is the fundamental switching path for MPLS. Without CEF, MPLS forwarding does not occur. For this reason, CEF is mandatory for MPLS to function.

https://forum.networklessons.com/t/mpls-labels-and-devices/1283/24?u=lagapides