ITU-T Recommendation E.427 Telephone network and ISDN. Quality of service, network management and traffic engineering. Collection and statistical analysis of special quality of service observation data for measurements of customer difficulties in the …

CCITT Recommendation E.426 Telephone network and ISDN. Quality of service, network management and traffic engineering. General guide to the percentage of effective attempts which should be observed for international telephone calls ITU-T Recommendation E.425 Series E: Overall network operation, telephone service, service operation and human factors. Network management – Checking the quality of the international telephone service. Internal automatic observations CCITT Recommendation E.424 Telephone network and ISDN. Quality of service, network management and traffic engineering. Test calls CCITT Recommendation E.428 Telephone network and ISDN. Quality of service, network management and traffic engineering. Connection retention CCITT Recommendation E.430 Telephone network and ISDN. Quality of service, network management and traffic engineering. Quality of service framework CCITT Recommendation E.431 Telephone network and ISDN. Quality of service, network management and traffic engineering. Service quality assessment for connection set-up and release delays