PerfIntervalCount
A counter associated with a performance measurement in a previous 15 minute measurement interval. In the case where the agent has no valid data available for a particular interval the corresponding object instance is not available and upon a retrieval request a corresponding error message shall be returned to indicate that this instance does not exist (for example, a noSuchName error for SNMPv1 and a noSuchInstance for SNMPv2 GET operation). In a system supporting a history of n intervals with IntervalCount(1) and IntervalCount(n) the most and least recent intervals respectively, the following applies at the end of a 15 minute interval: - discard the value of IntervalCount(n) - the value of IntervalCount(i) becomes that of IntervalCount(i-1) for n >= i > 1 - the value of IntervalCount(1) becomes that of CurrentCount - the TotalCount, if supported, is adjusted.