Multiprotocol Label Switching Architecture (MPLS) 2014-07-14 2018-02-27 Standards Action 0 Default/standard topology 1 IPv4 in-band management 2 IPv6 routing topology 3 IPv4 multicast topology 4 IPv6 multicast topology 5 IPv6 in-band management 6-3944 Unassigned (for future IGP topologies) 3945 Rainbow MRT MPLS MT-ID 3946 Default Profile MRT-Red MPLS MT-ID 3947 Default Profile MRT-Blue MPLS MT-ID 3948-3995 Unassigned (for future MRT-related values) 3996-4095 Reserved for Experimental Use 4096-65534 Unassigned (for MPLS topologies) 65535 Wildcard Topology