A tmnxMobGwSysGrpCardRedStChange notification is generated when the the redundancy state of this card changes. [CAUSE] A card failure will change the card redundancy state to 'notValid'. When an active card goes down, standby card will become active which will trigger a state change to 'active'. When a 'standbyInProg' card becomes in sync with the active card, state will be changed to 'standby'. [EFFECT] When card goes down, it will not be able to provide any mobile gateway services supported by the system. [RECOVERY] If the card goes down, operator's assistance is needed to get the card back online.
Sources for this description
Nokia networking MIB copies (LibreNMS/Observium Community)