This value, delivered only via the gvrpFailure notification per the source, explains why a GVRP VLAN registration attempt failed on a port: lackOfResources(1) for filtering-database exhaustion, registrationRestricted(2) if Restricted VLAN Registration blocked it, or unsupportedVID(3) if the requested VLAN ID isn't supported. A network administrator reviews this in the trap payload to distinguish between a capacity issue, an intentional security restriction, or an invalid VLAN request from a peer. For example, seeing unsupportedVID(3) would tell the admin a neighboring device requested registration for a VLAN ID this switch simply doesn't support, rather than a resource or policy problem.