Thresholding Overview - Cisco ASR 5000 Series Thresholding Configuration Manual

Chapter 1

Thresholding Overview

Thresholding on the system is used to monitor the system for conditions that could potentially cause errors or outage.
Typically, these conditions are temporary (i.e. high CPU utilization, or packet collisions on a network) and are quickly
resolved. However, continuous or large numbers of these error conditions within a specific time interval may be
indicative of larger, more severe issues. The purpose of thresholding is to help identify potentially severe conditions so
that immediate action can be taken to minimize and/or avoid system downtime.
The following thresholding models are supported by the system:
Alert: A value is monitored and an alert condition occurs when the value reaches or exceeds the configured high
threshold within the specified polling interval. The alert is then generated and/or sent at the end of the polling
interval.
In the example shown in the figure below, this model generates alerts during period 2, 3, and 5 at the point
where the count exceeded HT.
Alarm: Both high and low thresholds are defined for a value. An alarm condition occurs when the value reaches
or exceeds the configured high threshold within the specified polling interval. The alert is then generated
and/or sent at the end of the polling interval.
The alarm is cleared at the end of the first interval where the measured value is below the low threshold.
In the example shown in in the figure below, this model generates an alarm during period 2 when the count
exceeds HT. A second alarm is generated in period 6 when the count falls beneath LT. The second alarm
indicates a "clear" condition.
Figure 1.
HT
LT
HT = High Threshold
LT = Low Threshold
OL-25552-02
Example of Thresholding Model
1 2 3 4 5 6
Time
Cisco ASR 5000 Series Thresholding Configuration Guide ▄
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15