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Threshold Crossing Alerts Template

Threshold Crossing Alerts (TCAs) are preemptive, user-configurable alarms that are triggered when the specific thresholds are crossed.


They alarm on both rising and falling threshold crossing events (that is, floor and ceiling levels). For both levels, one value raises the alarm while another value clears it.


ON by Default

  • Appliance Capacity – Triggers when an appliance reaches 95% of its total flow capacity. It is not configurable and can be cleared only by an operator.

  • File-system utilization – Percent of non-Network Memory disk space filled by the appliance. This TCA cannot be disabled.

  • Tunnel latency – Measured in milliseconds, the maximum latency of a one-second sample within a 60-second span.

OFF by Default

  • LAN-side receive throughput – Based on a one-minute average, the LAN-side receive TOTAL for all interfaces.

  • WAN-side transmit throughput – Based on a one-minute average, the WAN-side transmit TOTAL for all interfaces.

  • TCAs based on an end-of-minute count:

    • Total number of flows

    • Total number of optimized flows

  • TCAs based on a one-minute average:

    • Tunnel loss post-FEC

    • Tunnel loss post-FEC

    • Tunnel OOP post-POC

    • Tunnel OOP post-POC

    • Tunnel reduction

    • Tunnel utilization (based on percent of configured maximum [system] bandwidth)

TCA Metrics

Times to Trigger – A value of 1 triggers an alarm on the first threshold crossing instance. The default sampling granularity (or rate or interval) is one minute.

This table lists the metrics of each type of threshold crossing alert:

Metrics for Threshold Crossing Alerts

TCA Name Unit Metric
Appliance Level    
WAN-side transmit throughput kbps Minute averageWAN–side transmit TOTAL for all interfaces
LAN-side receive throughput kbps Minute averageLAN–side receive TOTAL for all interfaces
Total number of optimized flows flows End of minute count
Total number of flows flows End of minute count
File-system-utilization % (non–Network Memory) End of minute count
Tunnel Level    
Tunnel latency msec Second-sampled maximum latency during the minute
Tunnel loss pre-FEC 1/10th % Minute average
Tunnel loss post-FEC 1/10th % Minute average
Tunnel OOP pre-POC 1/10th % Minute average
Tunnel OOP post-POC 1/10th % Minute average
Tunnel utilization % of configured bandwidth Minute average
Tunnel reduction % Minute average

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