PerfHighIntervalCount
A 64 bit 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. This definition is based on CounterBasedGauge64 TEXTUAL CONVENTION defined in RFC2856. The PerfHighIntervalCount type represents a non-negative integer, which may increase or decrease, but shall never exceed a maximum value, nor fall below a minimum value. The maximum value can not be greater than 2^64-1 (18446744073709551615 decimal), and the minimum value can not be smaller than 0. The value of a PerfHighIntervalCount, has its maximum value whenever the information being modeled is greater than or equal to its maximum value, and has its minimum value whenever the information being modeled is smaller than or equal to its minimum value. If the information being modeled subsequently decreases below (increases above) the maximum (minimum) value, the PerfHighIntervalCount also decreases (increases). Note that this TC is not strictly supported in SMIv2, because the 'always increasing' and 'counter wrap' semantics associated with the Counter64 base type are not preserved. It is possible that management applications which rely solely upon the (Counter64) ASN.1 tag to determine object semantics will mistakenly operate upon objects of this type as they would for Counter64 objects. This textual convention represents a limited and short-term solution, and may be deprecated as a long term solution is defined and deployed to replace it.