A tmnxOspfNgNbrStateChange notification is generated when there has been a change in the state of a non-virtual OSPF neighbor. This notification should be generated when the neighbor state regresses (e.g., goes from Attempt or Full to 1-Way or Down) or progresses to a terminal state (e.g., 2-Way or Full). When a neighbor transitions from or to Full on non-broadcast multi-access and broadcast networks, the notification should be generated by the designated router. A designated router transitioning to Down will be noted by the tmnxOspfNgIfStateChange notification.
Sources for this description
Netdisco MIB archive copiesNokia networking MIB copies (LibreNMS/Observium Community)