Value,Purpose,Reference 0,Default/standard topology,[RFC7307] 1,IPv4 in-band management,[RFC7307] 2,IPv6 routing topology,[RFC7307] 3,IPv4 multicast topology,[RFC7307] 4,IPv6 multicast topology,[RFC7307] 5,IPv6 in-band management,[RFC7307] 6-3944,Unassigned (for future IGP topologies), 3945,Rainbow MRT MPLS MT-ID,[RFC8320] 3946,Default Profile MRT-Red MPLS MT-ID,[RFC8320] 3947,Default Profile MRT-Blue MPLS MT-ID,[RFC8320] 3948-3995,Unassigned (for future MRT-related values), 3996-4095,Reserved for Experimental Use,[RFC7307] 4096-65534,Unassigned (for MPLS topologies), 65535,Wildcard Topology,[RFC7307]