risingAlarm

RMON-MIB::risingAlarm #

The SNMP trap that is generated when an alarm entry crosses its rising threshold and generates an event that is configured for sending SNMP traps.

Variables #

  • alarmIndex
  • alarmVariable
  • alarmSampleType
  • alarmValue
  • alarmRisingThreshold

Definitions #

alarmIndex
An index that uniquely identifies an entry in the alarm table. Each such entry defines a diagnostic sample at a particular interval for an object on the device.
alarmVariable
The object identifier of the particular variable to be sampled. Only variables that resolve to an ASN.1 primitive type of INTEGER (INTEGER, Integer32, Counter32, Counter64, Gauge, or TimeTicks) may be sampled. Because SNMP access control is articulated entirely in terms of the contents of MIB views, no access control mechanism exists that can restrict the value of this object to identify only those objects that exist in a particular MIB view. Because there is thus no acceptable means of restricting the read access that could be obtained through the alarm mechanism, the probe must only grant write access to this object in those views that have read access to all objects on the probe. During a set operation, if the supplied variable name is not available in the selected MIB view, a badValue error must be returned. If at any time the variable name of an established alarmEntry is no longer available in the selected MIB view, the probe must change the status of this alarmEntry to invalid(4). This object may not be modified if the associated alarmStatus object is equal to valid(1).
alarmSampleType
The method of sampling the selected variable and calculating the value to be compared against the thresholds. If the value of this object is absoluteValue(1), the value of the selected variable will be compared directly with the thresholds at the end of the sampling interval. If the value of this object is deltaValue(2), the value of the selected variable at the last sample will be subtracted from the current value, and the difference compared with the thresholds. This object may not be modified if the associated alarmStatus object is equal to valid(1).
alarmValue
The value of the statistic during the last sampling period. For example, if the sample type is deltaValue, this value will be the difference between the samples at the beginning and end of the period. If the sample type is absoluteValue, this value will be the sampled value at the end of the period. This is the value that is compared with the rising and falling thresholds. The value during the current sampling period is not made available until the period is completed and will remain available until the next period completes.
alarmRisingThreshold
A threshold for the sampled statistic. When the current sampled value is greater than or equal to this threshold, and the value at the last sampling interval was less than this threshold, a single event will be generated. A single event will also be generated if the first sample after this entry becomes valid is greater than or equal to this threshold and the associated alarmStartupAlarm is equal to risingAlarm(1) or risingOrFallingAlarm(3). After a rising event is generated, another such event will not be generated until the sampled value falls below this threshold and reaches the alarmFallingThreshold. This object may not be modified if the associated alarmStatus object is equal to valid(1).

Meaning #

The RMON-MIB::risingAlarm SNMP trap is generated when an alarm entry crosses its rising threshold and meets the conditions for sending SNMP traps. This trap is triggered when the sampled value of a monitored object exceeds the rising threshold, indicating a significant change in the object’s value.

Impact #

Receiving this trap may indicate a potential issue with the monitored object or the system being monitored. The rising threshold crossing may signal an anomaly, error, or unexpected behavior that requires attention from network administrators or operators. Ignoring this trap may lead to undetected problems, performance degradation, or even system crashes.

Diagnosis #

To diagnose the issue, follow these steps:

  1. Identify the alarmIndex, which uniquely identifies the entry in the alarm table.
  2. Determine the object being monitored (alarmVariable) and its current value (alarmValue).
  3. Verify the sampling method (alarmSampleType) and the rising threshold (alarmRisingThreshold) that was exceeded.
  4. Analyze the historical data and recent trends to understand the cause of the rising threshold crossing.
  5. Check the system logs and other monitoring tools for correlated events or errors.

Mitigation #

To mitigate the issue, consider the following steps:

  1. Investigate and address the root cause of the rising threshold crossing.
  2. Adjust the alarmRisingThreshold to a more suitable value, if necessary.
  3. Implement additional monitoring or logging to provide more insights into the system behavior.
  4. Consider setting up additional alarm entries for similar variables to provide early warnings for potential issues.
  5. Develop and implement a corrective action plan to prevent similar events from occurring in the future.
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