Everything worth knowing, nothing that isn't.
What it actually does
For every call attempt routed over a trunk, the signalling layer records whether the call reached an answered state (the called party picked up) or terminated in another disposition (busy, no answer, network failure, congestion). ASR is answered ÷ seized × 100. Operators compute ASR per destination prefix, per route, per hour. The complement, NER (Network Effectiveness Ratio), filters out user-caused non-answers (busy, no-answer) to isolate network-quality issues. Together they give a complete view of route health.
Why it matters commercially
ASR is the commercial scorecard for wholesale voice. A premium tier-1 route to a developed market sits at 55-70% ASR; a low-quality grey route is often under 30%. Voice buyers re-rank their route preferences daily based on ASR + ACD (Average Call Duration) — a low-ASR route is dropped from the LCR cascade. For contact centres, ASR drives campaign sizing: if ASR drops 5 points overnight, the dialler needs to seize 8-10% more calls to maintain the same answered-conversation count. BroadNet's Signaling & CDR Intelligence (/platforms/signaling-cdr) computes ASR per route per minute and alerts on degradation.
Latency, scale, and compliance angle
ASR is computed continuously from CDRs at carrier scale — hundreds of millions of call attempts per day on a tier-1 network. The classic computation is per 15-minute window per destination prefix, with rolling 1-hour and 24-hour aggregates. Anomaly-detection layered on top catches ASR collapse events within minutes. Compliance angle: ASR thresholds appear in wholesale interconnect SLAs ("ASR ≥ X% to destination Y"); breach triggers service credits or termination clauses.
Privacy and compliance considerations
ASR computation requires CDR access, which contains MSISDN-level data. In regulated markets (EU, KSA, UAE) the CDR store is in scope for data-protection law. Aggregate ASR figures (per route, per hour) are not personal data; the underlying CDRs that produce them are. Mature operator reporting separates the two and applies strict access control to the raw CDR feed.