Router(config)# ip cef [distributed]
CEF operation can be verified with show ip cef.
MPLS is enabled by default on routers which support it. It can be disabled with no mpls ip.
MPLS and Label Distribution Protocol (LDP) must be enabled per interface.
Router(config-if)# mpls label protocol ldp
Router(config-if)# mpls ip
The MTU on an MPLS interface must be raised by four bytes for each potential label in a stack.
Router(config-if)# mpls mtu 1512
Setting the MTU with mpls mtu only modifies the MTU for MPLS packets, rather than all interface traffic.
All intermediate devices must support jumbo frames as well.
The status of LDP neighbors can be verified with show mpls ldp neighbor.