Maintenance Manager works within the constraints of the limited use license by utilising the internal HSQL database to store the maintenance records and this incurs no extra Netcool licensing costs.The maintenance window definitions consist of fields used to match incoming alerts to a particular window e.g. a maintenance window can be configured to apply to all alerts issued from a specific Node. The functionality offered by Impact means that the matching performed can be more flexible, such as supporting the use of regular expressions.