Description: This trap is generated by the SNMP Agent when the Agent has detected a transition in the link condition between the Radio and the NMU.. This trap may be filtered by 'mgmtNMULinkTrapControl', which is a specific Trap control that can be used to specifically enable or disable this trap. See the definition of this variable above for details about this filter, and the other trap filtering mechanisms. The 'trapSequenceNumber,' variable bound within the trap can be used by management stations and network administrators to detect when a trap has been lost during transmission. The 'mgmtNMULinkSeverity' variable bound within the trap indicates the configured severity level associated with this event. A value of 'LINK-UP', indicates that the link between the Radio and NMU is not in an alarm state. A value of 'LINK-DOWN', however, means that the link between the two entities might be down or one side stops responding to the othe side. The row/column variables included in the trap are: system.trap.trapSequenceNumber; radio.mgmt.mgmtNMULinkSeverity.