VNA Thresholding Limitations for Specific SDN Engine API Metrics

Products

• Network Observability
• Virtual Network Assurance
• CA Performance Management

Issue/Introduction

When configuring a Threshold Profile in DX NetOps Performance Management for the VNA Gateway device (specifically using the "Successful API Requests" metric), administrators may find that the threshold does not trigger even when a specific SDN endpoint (e.g., Viptela, Cisco ACI) is unreachable or experiencing authentication failures.

Metrics for "VNA Engine API Requests" or "VNA Engine Successful Requests" remain non-zero, preventing alerts based on a fixed value (e.g., alerting when requests drop below 1).

Environment

• DX NetOps Virtual Network Assurance (All Versions)
• DX NetOps Performance Management

Cause

This behavior occurs due to how the VNA Gateway device handles component synchronization for self-monitoring:

1. Aggregate Metrics: VNA does not sync individual engine/plugin components for the VNA GW device. Consequently, metrics such as "Successful API Requests" are collected as a single aggregate value representing all active engines and self-monitoring tasks.
2. Global Thresholds: Thresholds applied to the VNA GW device check for one combined value across all engines rather than evaluating each engine or plugin independently.
3. Internal Traffic: Successful requests from other functional plugins or internal VNA self-monitoring processes will keep the aggregate success count above zero, even if one specific SDN endpoint has failed.

Resolution

There is currently no dedicated metric isolated purely for a specific SDN endpoint on the VNA GW device that can be used for individual thresholding.