If the event represents a threshold crossing event, the two
objects h3cDot3OamEventWindowHi and h3cDot3OamEventWindowLo form an
unsigned 64-bit integer yielding the window over which the
value was measured for the threshold crossing event (e.g. 5,
when 11 occurrences happened in 5 seconds while the threshold
was 10). The two objects are combined as:
h3cDot3OamEventLogWindow = ((2^32) * h3cDot3OamEventLogWindowHi)
+ h3cDot3OamEventLogWindowLo
Otherwise, this value is returned as all F's (0xFFFFFFFF) and
adds no useful information.