Loopback-based MPLS over IPv4/IPv6 GRE and UDP encapsulation

This feature enables loopback-based transport of MPLS traffic across non-MPLS IPv4 or IPv6 networks using GRE or UDP encapsulation. MPLS-labeled packets are encapsulated with outer IP and GRE or UDP headers and forwarded through loopback-based tunnel interfaces. You can use this capability to extend MPLS connectivity across standard IP infrastructure while preserving MPLS forwarding between tunnel endpoints. UDP encapsulation can also provide source-port entropy for more effective ECMP load balancing across the intermediate IP network.