CONTENTS

�1���� Introduction
������� 1.1���� Purpose
������� 1.2���� Scope
������� 1.3���� Abbreviations
������� 1.4���� Related Recommendations
������� 1.5���� Methodology of availability specification
������� 1.6���� Organization of this Recommendation
�2���� ISDN 64 kbit/s packet-switched connection type (PSCT) availability performance
������� 2.1���� PSCT availability function
������� 2.2���� PSCT availability parameters
������� 2.3���� PSCT availability objectives
�3���� ISDN 64 kbit/s circuit-switched connection type (CSCT) availability performance
������� 3.1���� CSCT availability function
������� 3.2���� CSCT availability parameters
������� 3.3���� CSCT availability objectives
�4���� ISDN 64 kbit/s dedicated-circuit connection type (DCCT) availability performance
������� 4.1���� DCCT availability function
������� 4.2���� DCCT availability parameters
������� 4.3���� DCCT availability objectives
Annex A � Sampling estimation of ISDN availability parameters
������� A.1���� Estimation of the availability state of switched ISDN 64 kbit/s connection type portions
������� A.2���� Procedure for estimating availability of switched ISDN 64 kbit/s connection type portions
������� A.3���� Procedure for estimating mean time between connection portion outages of switched ISDN 64 kbit/s connection types
������� A.4���� Statistical basis of Phase I minimal test with N = 4
������� A.5���� Application of the sequential probability ratio test (SPRT) to the Phase I minimal test for availability
Annex B � Representative end-to-end availability performance of ISDN 64 kbit/s connection types
������� B.1���� Representative end-to-end design availability performance of ISDN 64 kbit/s packet‑switched connection type (PSCT)
������� B.2���� Derivation of the end-to-end �95th percentile� availability from �worst-case� availabilities of connection portions
Annex C � Related availability parameters
Annex D � Factors to be specified in reporting ISDN availability performance of 64 kbit/s connection types
������� D.1���� Planned hours of connection portion availability