This unsigned integer carries the VNI (VXLAN Network Identifier) value associated with a tunnel-to-VRF mapping event, and like its sibling objects is accessible only for notifications. It lets a trap receiver identify which VXLAN segment was involved when an hwNvo3VxlanVni2Vrf, hwNvo3VxlanVni2VrfClear, hwNvo3VxlanVrf2Vni, or hwNvo3VxlanVrf2VniClear notification fires. For example, an hwNvo3VxlanVni2Vrf trap carrying hwNvo3TnlVniId 5000 tells the admin that VNI 5000 was just mapped to a VRF instance and cannot be mapped to another VRF while that mapping stands.