CONTENTS

1)���� Clause 
2)���� References
3)���� New Annex A
Annex A� �� Inter-exchange signalling data link layer protocol in Private Integrated Services Networks (PISNs) � Overview of the functions of the data link layer for the support of inter-exchange signalling in PISNs and additions to concepts and terminology to accommodate PISN inter-exchange requirements
������� A.1���� Overview of the functions and procedures of the data link layer
����������������� A.1.1���� General
����������������� A.1.2���� Overview of data link layer structure
������� A.2���� Concepts and terminology
����������������� A.2.1���� General
����������������� A.2.2���� Data Link Connection Identification (DLCI)
���� �������������A.2.3���� Data link states
����������������� A.2.4���� Service characteristics