A VoIP route can look profitable on paper yet quietly drain revenue through failed calls and unexpectedly short conversations. For wholesale telecom providers identifying these problems early requires more than checking termination rates — it requires consistent monitoring of call performance.
Answer-Seizure Ratio (ASR) and Average Call Duration (ACD) are two essential metrics that help operators evaluate route behavior and investigate performance changes. When combined with call detail records (CDRs) and cost analysis they provide a practical foundation for identifying underperforming routes and making better routing decisions.
Understanding ASR and ACD in VoIP Route Monitoring
What ASR Reveals About Call Completion
ASR measures the percentage of eligible call attempts that result in answered calls. A commonly used calculation is:
ASR = Answered Call Attempts ÷ Total Eligible Call Attempts × 100
For example if a route receives 2,000 eligible call attempts and 1,300 are answered its ASR is 65%.
A declining ASR may indicate destination problems carrier issues signaling failures or changes in calling patterns. However a low value does not automatically prove that a route is defective because unanswered calls and traffic composition also influence the result.
What ACD Reveals About Connected Calls
ACD measures the average duration of connected calls over a defined period. It is commonly calculated by dividing total connected call duration by the number of answered calls.
If 600 answered calls generate 1,800 connected minutes the ACD is three minutes.
A sudden drop in ACD may warrant investigation into premature disconnections routing changes or shifts in customer behavior. Longer calls are not automatically better either because duration depends on the purpose and type of traffic.
Together ASR and ACD help operators understand two different aspects of route performance: how often calls connect and how long connected calls typically last.
Warning Signs That a VoIP Route Is Underperforming
Recognizing Changes Before They Affect Customers
A route rarely announces that it is becoming unreliable. Instead performance changes appear gradually in call statistics and operational reports. Monitoring ASR and ACD helps operators identify these changes before they become persistent problems.
Watch for these warning signs:
Falling ASR: Fewer eligible call attempts result in answered calls.
Declining ACD: Connected calls become shorter than the route's normal baseline.
Sudden metric fluctuations: Performance changes sharply during a specific time window.
Inconsistent destination performance: A route performs well for some destinations but poorly for others.
Repeated carrier-related failures: CDRs show recurring rejection codes or unsuccessful attempts associated with a particular route.
Example: Finding a Hidden Performance Problem
Suppose a route's ASR falls from 68% to 42% over several hours. At the same time its ACD drops from 3.2 minutes to 1.4 minutes.
These changes justify an investigation but do not establish the cause. The operator should examine call failure codes, destination patterns and carrier performance to determine whether the issue is related to signaling, traffic composition or another factor.
Comparing the route against its own historical performance is often more useful than applying a universal ASR or ACD threshold to every destination.
How to Analyze ASR and ACD Together
Why One Metric Is Never Enough
ASR and ACD measure different aspects of call behavior. Looking at only one can lead to incorrect conclusions about route quality.
Consider four possible patterns:
High ASR and stable ACD: Call completion and connected-call duration are consistent with expectations.
Low ASR and stable ACD: Fewer calls connect but answered calls have typical durations.
High ASR and falling ACD: Many calls connect but conversations are becoming shorter.
Falling ASR and falling ACD: Both completion and connected-call duration warrant investigation.
These patterns are diagnostic clues rather than definitive quality ratings. For example a short ACD could reflect legitimate brief calls while a low ASR may be normal for destinations with many unanswered attempts.
Use a Practical Comparison
Imagine two routes carrying comparable traffic to the same destination.
Route A has an ASR of 72% and an ACD of 3.4 minutes. Route B has an ASR of 54% and an ACD of 2.1 minutes.
Route A appears stronger on both metrics in this example. Before changing traffic allocation the operator should confirm that both reports use the same measurement definitions and cover comparable time periods.
The next step is to compare termination rates, failure codes and customer requirements. This helps determine whether the apparent performance difference justifies a routing change.
Using Monitoring Data to Optimize Routing Decisions
From Performance Analysis to Action
Once an underperforming route has been identified the next task is deciding what to do about it. Depending on the findings operators may investigate the carrier, adjust routing priorities or temporarily reduce traffic through the affected route.
A structured workflow helps prevent unnecessary changes:
Identify a meaningful deviation from the route's baseline.
Verify that the sample size is sufficient for a reliable comparison.
Examine CDRs and failure codes to narrow down possible causes.
Compare alternative routes for the same destination.
Review the cost and expected performance of each alternative.
Make a controlled routing change and monitor the result.
Why Dynamic Routing Can Help
Some softswitch platforms support routing strategies based on measured performance. Sippy Softswitch documents quality-based routing that can monitor ACD, ASR and post-dial delay across vendor connections.
DeNovoLab Class 4 Fusion also documents routing strategies that include ASR-based and ACD-based routing alongside least-cost and other routing methods. Its platform overview describes integrated routing, switching, reporting and CDR storage.
These approaches can reduce dependence on manual route selection. However automated decisions need appropriate thresholds and safeguards. A temporary performance dip should not automatically trigger repeated route changes without sufficient evidence.
Choosing Telecom Software for ASR and ACD Monitoring
What to Look for in a Softswitch
The usefulness of ASR and ACD monitoring depends on the quality of the underlying data and how easily teams can act on it.
Look for capabilities such as:
Route-level and carrier-level performance reports
Filters for destination and time period
CDR access with detailed call outcomes
Configurable alerts and performance thresholds
Dynamic routing based on supported quality metrics
Integration with billing and cost analysis
Historical reporting for trend comparisons
These capabilities help operators move from observing metrics to investigating problems and making informed changes.
DeNovoLab Compared With Other Platforms
DeNovoLab Class 4 Fusion combines switching routing billing reporting and monitoring capabilities within an integrated telecom environment. Its published platform overview also describes centralized CDR data and support for high-volume telecom reporting.
Sippy provides documented quality-based routing features for vendor connections while PortaOne's PortaSwitch ecosystem includes routing and billing workflows alongside call records and reporting.
The differences should be evaluated against the actual requirements of each operator. Businesses should compare reporting detail, routing controls, integration needs and operational costs rather than assume that one platform is universally superior.
For a wholesale VoIP provider the priority is choosing software that makes route problems visible and provides practical ways to respond.
Best Practices for Continuous Route Performance Monitoring
Establish a Repeatable Monitoring Routine
ASR and ACD monitoring is most effective when it becomes part of daily network operations rather than an occasional report review.
Use these practices to improve consistency:
Set destination-specific baselines: Different destinations and traffic types naturally produce different results.
Review trends over multiple periods: Compare recent performance with historical data.
Use appropriate sample sizes: Avoid reacting to small numbers of calls.
Investigate failure codes: Determine why calls failed instead of relying on percentages alone.
Include commercial data: Compare route performance with termination costs and expected margins.
Automate meaningful alerts: Set thresholds that reflect normal variation and business requirements.
Verify every routing adjustment: Measure whether the change improved performance without increasing costs unnecessarily.
Measure Business Outcomes
A successful monitoring process should do more than improve a dashboard. It should help reduce avoidable routing failures, support better carrier selection and make operational problems easier to investigate.
Track changes in call completion, route costs, customer complaints and recurring failure patterns. Reviewing these indicators together provides a more complete picture of whether routing improvements are delivering business value.
Conclusion: Turn Route Monitoring Into Better Telecom Decisions
ASR and ACD monitoring helps wholesale VoIP providers recognize underperforming routes by revealing changes in call completion and connected-call duration. These metrics become more valuable when combined with CDR analysis, carrier performance data and cost comparisons.
The objective is not to maximize ASR or ACD in isolation. It is to identify the reasons behind performance changes and choose routes that meet customer expectations while supporting sustainable margins.
DeNovoLab Class 4 Fusion brings switching, routing, billing, reporting and monitoring capabilities together for telecom operators seeking a more integrated approach to route management.
Want to improve visibility into your VoIP routes? Visit www.denovolab.com to explore Class 4 Fusion and evaluate how its routing and monitoring capabilities can support your telecom operations.
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