csOc3TimeElapsed is a read-only counter of the seconds elapsed since the start of the current 15-minute performance-measurement period on this OC3 port. Like its DS3 counterpart, it lets an admin judge how significant the error counts in the current interval are, since a burst of errors early in the window is more urgent than the same count near the end of it. For example, seeing csOc3SectionCurrentESs already at 20 while csOc3TimeElapsed shows only 45 seconds elapsed tells an admin the Section layer is degrading unusually fast this interval.