Electronic and Postal Communications (Quality of Service) G.N. No. 416 (contd) _______ THIRD SCHEDULE _______ (Made under Regulation 10) QUALITY OF SERVICE PARAMETERS FOR INTERNATIONAL TELEPHONE SERVICES S/NO Definition 1 The relationship between the number of seizures that result in an answer signal and the total number of seizures. Measurement Target Values Answer Seizure Ratio (ASR) Percentage of seizures For active test calls placed by resulting in answer signal some test systems [ITU-T Rec. E.426]: (ITU-T Rec. E.425) Effective call attempts should ASR: ≥ 80%. be more than 60%. NER: ≥ 90%. 2 The relationship between the number of seizures and the sum of the number of seizures resulting in either an answer message, or a user busy, or a ring no answer, or in the case of ISDN a terminal rejection/unavailability 3 The call set up time can be defined as the time interval from the instant the user initiates a connection request until the complete message indicating call disposition is received by the calling terminal. 4 Network Efficiency Ratio (NER) Percentage of seizures For active test calls placed by resulting in answer signal or some test systems: NER: ≥ user failure(ITU-T Rec. 90%. E.425) Effective call attempts should be more than 60%. Call set-up time Mean values (in seconds) (ITU-T Rec. E.721; ITU-T Rec. E.771) Mean value of International call set-up time: < 8sec Blocked Call Rate Percentage of unsuccessful calls. An unsuccessful call is call attempt to a valid number, while in a coverage area, where Probability of end-to-end blocking (ITU-T Rec. E.771) 17 Mean value of end-to-end call blocking: < 5%