Quality Metrics
Ref: ITU-T Recommendation E.411
ASR
Answer Seizure Ratio
Direct Telecom Definition • Carrier Industry Standard
The percentage of answered telephone calls relative to the total number of call attempts (seizures).
Technical Definition & Carrier Engineering Standards
ASR is one of the most critical wholesale VoIP quality metrics. It measures the network efficiency and termination route health by calculating the proportion of call seizures that result in a connected answer state (SIP 200 OK). High ASR indicates reliable bilateral routes and accurate CLI delivery.
Standard Formula / Protocol Algorithm
ASR (%) = (Total Answered Calls / Total Seizures) × 100