CONTENTS

 1     Introduction
 2     Reference configuration at the user-network interface
        2.1     Functional groups and reference points
        2.2     Examples of physical realizations
        2.3     Basic characteristics of the interfaces at TB and SB reference points
        2.4     Relationship between ISDN interfaces
        2.5     Application of B-ISDN model to functional groups
 3     Physical layer information flows and interface functions
        3.1     Relation with other sublayers or entities
        3.2     Modes of operation
        3.3     Interface function
 4     UNI related OAM functions
Annex  A – Alphabetical list of abbreviations used in this Recommendation