3.1.5 Timer Events
When the TableMaintenanceTimer expires, the server MAY<9> perform the following operations on its tables:
For each entry in the ServerVolumeTable, if the difference between the RefreshTime field and the CurrentRefreshTime value is more than 90, then the entry MUST be deleted.
Similarly, for each entry in the FileTable, if the difference between the RefreshTime field and the CurrentRefreshTime value is more than 90, then the entry MUST be deleted.
The CurrentRefreshTime value MUST be incremented.