This object sets the alarm severity, major or minor, raised when a statistical threshold is exceeded on the SONET section layer, with the MIB noting that by default a threshold crossing alarm (TCA) does not raise any alarm at all. An administrator must explicitly configure this to major or minor if they want threshold crossings on section-layer error counters to generate a visible alarm rather than being silently recorded. For example, leaving this at its default of none would mean that even if the errored-seconds threshold is repeatedly exceeded on the section layer, no alarm would be raised to alert the administrator.