CONTENTS

 1     Scope
        1.1     Service Requirements
        1.2     High Level Requirements
        1.3     Guidelines for protocol development
        1.4     Functional Reference Model
 2     References
 3     Definitions
        3.1     Functional Model Definitions
        3.2     Definition of Signalling Flow Objects
 4     Abbreviations
 5     Requirements
        5.1     General
        5.2     Addressing
                  5.2.1     Call Control
                  5.2.2     BNC Control
        5.3     Routing
                  5.3.1     Call Control
                  5.3.2     BIWF Selection Control
                  5.3.3     BNC Control
        5.4     Symmetry of call and bearer control
                  5.4.1     Call Control
                  5.4.2     BNC Control
        5.5     Connection configuration
        5.6     Essential features of the underlying signalling transport
        5.7     Flow control
        5.8     Independence from underlying signalling transport
        5.9     Concatenation
       5.10     Contention resolution
       5.11     Error reporting
       5.12     Unrecoverable failures
       5.13     Forward and backward compatibility
       5.14     Separation between signalling controls
       5.15     Performance Requirements
       5.16     Codec Negotiation
       5.17     Codec Modification
 6     Signalling Procedures
        6.1     Successful Call Set-up
                  6.1.1     Call Establishment
                  6.1.2     Bearer establishment
        6.2     Unsuccessful Set-up
        6.3     Release of a Successful Call
        6.4     Error Handling
        6.5     Echo Control Procedure
        6.6     Blocking and unblocking
        6.7     Call Automatic Repeat attempts
        6.8     Dual Seizure
        6.9     Reset
       6.10     Support of Codec Negotiation
       6.11     Support of Codec Modification
 7     General Signalling Transport Requirements
 8     Backbone Network Signalling Flows
        8.1     Successful Backbone Call and Backbone Network Connection Establishment
                  8.1.1     Establishment of a Backbone Network Connection
                  8.1.2     Establishment of a Backbone Network Connection with Transit Serving Node
                  8.1.3     Reuse of an Idle Backbone Network Connection
                  8.1.4     Establishment of a Backbone Network Connection with Codec Negotiation
                  8.1.5     Establishment of a Backbone Network Connection with Codec Negotiation and Transit Serving Node
                  8.1.6     Forward Connection Set-up with Call Mediation Node
                  8.1.7     Codec Modification Signalling Requirement Flows
        8.2     Call Release
                  8.2.1     Call Release
                  8.2.2     Call Release with Mediation Node
                  8.2.3     Call Release with Transit Serving Node
        8.3     Backbone Network Connection Release
Annex A - Capability Set 1 Services and Functions