Critical alarms indicate the system or certain components within the system are unusable. These alarms require immediate attention.

Major alarms identify failures that are causing a critical degradation of service. These alarms require immediate attention.

Minor alarms identify failures that are causing service degradation. These failures do not cause the system to be inoperable.

Warning alarms identify failures that cause no significant degradation of service. The system does not report warning alarms to a services organization.