CONTENTS

 1     Scope
 2     References
 3     Definitions
 4     Abbreviations
 5     Conventions
 6     General
        6.1     Introduction to Recommendation structure
        6.2     Messages, parameters and information elements
        6.3     Use of Application Transport Mechanism
                  6.3.1     Introduction
                  6.3.2     Application Transport Instruction Indicators
                  6.3.3     Handling of Addressing Information
                  6.3.4     BAT ASE at a CMN
        6.4     Bearer control tunnelling
                  6.4.1     Bearer control tunnelling procedure
 7     Successful basic call set-up
        7.1     Introduction
        7.2     Forward address signalling - En bloc operation
                  7.2.1     Actions required at the originating SN
                  7.2.2     Actions required at an intermediate SN
                  7.2.3     Actions required at an intermediate CMN
                  7.2.4     Actions required at an outgoing gateway SN
                  7.2.5     Actions required at an outgoing gateway CMN
                  7.2.6     Actions required at an incoming gateway SN
                  7.2.7     Actions required at an incoming gateway CMN
                  7.2.8     Actions required at the destination SN
                  7.2.9     Called party number for operator calls
                 7.2.10     Called number for calls to testing and measuring devices
        7.3     Forward address signalling - overlap operation
                  7.3.1     Actions required at the originating SN
                  7.3.2     Actions required at an intermediate SN/CMN
                  7.3.3     Actions required at the destination SN
        7.4     Outgoing bearer set-up procedure
                  7.4.1     Per-call bearer set-up in forward direction
                  7.4.2     Per-call bearer set-up in backward direction
                  7.4.3     Per-call bearer set-up using bearer control tunnelling - fast set-up
                  7.4.4     Per-call bearer set-up using bearer control tunnelling - delayed forward
                  7.4.5     Per-call bearer set-up using bearer control tunnelling - delayed backward
        7.5     Incoming bearer set-up procedure
                  7.5.1     Per-call bearer set-up in forward direction
                  7.5.2     Per-call bearer set-up in backward direction
                  7.5.3     Per-call bearer set-up using bearer control tunnelling - fast set-up
                  7.5.4     Per-call bearer set-up using bearer control tunnelling - delayed forward
                  7.5.5     Per-call bearer set-up using bearer control tunnelling - delayed backward
        7.6     Continuity message
                  7.6.1     Actions required at the originating SN
                  7.6.2     Actions required at an intermediate SN
                  7.6.3     Actions required at a CMN
                  7.6.4     Actions required at the destination SN
        7.7     Address complete message or Connect message
                  7.7.1     Actions required at the destination SN
                  7.7.2     Actions required at an intermediate SN/CMN
                  7.7.3     Actions required at an outgoing gateway SN/CMN
                  7.7.4     Actions required at an incoming gateway SN/CMN
                  7.7.5     Actions required at the originating SN
                  7.7.6     Internal through connection of the bearer path and awaiting answer indication at the destination SN
        7.8     Answer message
                  7.8.1     Actions required at the destination SN
                  7.8.2     Actions required at an intermediate SN/CMN
                  7.8.3     Actions required at an outgoing gateway SN/CMN
                  7.8.4     Actions required at an incoming gateway SN/CMN
                  7.8.5     Actions required at the originating SN
                  7.8.6     Return of answer from automatic terminals
        7.9     Access Transport Parameter
       7.10     Storage and release of Initial Address Message information
 8     Additional set-up procedures
        8.1     Introduction
        8.2     Call Progress
                  8.2.1     Actions required at the destination SN
                  8.2.2     Actions required at an intermediate SN/CMN
                  8.2.3     Actions required at the originating SN
        8.3     Codec Negotiation
                  8.3.1     SN initiating codec negotiation
                  8.3.2     SN transiting codec negotiation
                  8.3.3     SN terminating codec negotiation
                  8.3.4     Outgoing bearer set-up procedure
                  8.3.5     Incoming bearer set-up procedure
                  8.3.6     Abnormal cases
        8.4     Echo Control
                  8.4.1     General
                  8.4.2     Procedures
        8.5     Propagation delay procedure
                  8.5.1     Procedure
        8.6     Signalling procedures for connection type allowing fallback
                  8.6.1     Actions in the forward direction
                  8.6.2     Actions in the backward direction - fallback indicated before answer
                  8.6.3     Actions in the backward direction - fallback indicated at answer
                  8.6.4     Actions in the backward direction - fallback does not occur
                  8.6.5     Echo control for connection types allowing fallback
        8.7     Transit network selection (national use)
        8.8     Support for Temporary Alternative Routing (TAR)
        8.9     Hop counter procedure
                  8.9.1     Actions at the initiating SN/CMN
                  8.9.2     Actions at an intermediate SN/CMN
                  8.9.3     Actions at the destination SN
       8.10     Charging
       8.11    Access delivery indication
       8.12     Information messages
                 8.12.1     Requesting information (national use)
                 8.12.2     Sending solicited information (national use)
                 8.12.3     Receiving a solicited information message (national use)
       8.13     Call collect request procedure
       8.14     Calling party number
       8.15     Calling Geodetic location procedure
                 8.15.1     Introduction
                 8.15.2     Transfer of Geodetic information
       8.16     Inter-nodal traffic group identification
                 8.16.1     Sending Inter-nodal traffic group identification
                 8.16.2     Receiving Inter-nodal traffic group identification
       8.17     Carrier selection information (national use)
                 8.17.1     Action required at the originating SN
                 8.17.2     Action required at an intermediate SN/CMN within the originating network
                 8.17.3     Action required at an outgoing national gateway SN/CMN
                 8.17.4     Action required at an incoming national gateway SN/CMN
                 8.17.5     Action required at the destination SN
                 8.17.6     Action required at an international gateway SN/CMN
       8.18     Global Call Reference
       8.19     Bearer Control Unit Identifier (BCU-ID)
                 8.19.1     General
                 8.19.2     Actions at an SN
                 8.19.3     Actions at a CMN
                 8.19.4     Selection of BCU-ID
                 8.19.5     Forward/Backward Bearer Establishment
       8.20     Out-of-band transport of DTMF and Tone information
                 8.20.1     Introduction
                 8.20.2     Procedures
 9     Unsuccessful call set-up
        9.1     Introduction
        9.2     Actions at a CSF initiating a release message
        9.3     Actions at an intermediate SN/CMN
        9.4     Actions at the controlling SN/CMN (i.e. the SN/CMN controlling the call)
                  9.4.1     Actions at a controlling SN
                  9.4.2     Actions at a controlling CMN
        9.5     Tones and announcements
                  9.5.1     Tones and announcements at an SN
                  9.5.2     Tones and announcements at a CMN
        9.6     Address incomplete
10     Mid-call procedures
       10.1     Introduction
       10.2     Suspend and resume
                 10.2.1     Suspend
                 10.2.2     Resume
                 10.2.3     Expiration of timer T6 or timer T38
       10.3     Forward Transfer message
       10.4     Codec modification/mid-call codec negotiation procedures
                 10.4.1     SN initiating codec modification
                 10.4.2     SN terminating codec modification
                 10.4.3     SN transiting codec modification
                 10.4.4     SN initiating mid-call codec negotiation
                 10.4.5     SN terminating mid-call codec negotiation
                 10.4.6     SN transiting mid-call codec negotiation
                 10.4.7     Abnormal codec modification/mid-call codec negotiation cases
11     Normal call release
       11.1     Introduction
       11.2     Release initiated by a calling party
       11.3     Release initiated by a called party
       11.4     Release initiated by the network
       11.5     Release sending procedure
       11.6     Release reception procedure
       11.7     Collision of Release messages
       11.8     Charging (national use)
12     Network features
       12.1     Introduction
       12.2     Simple segmentation
       12.3     Pre-release information transport
       12.4     Automatic repeat attempt
       12.5     Blocking and unblocking of CIC values
                 12.5.1     Introduction
                 12.5.2     CIC group blocking procedures
                 12.5.3     Interactions between CIC blocking and call set-up procedures
                 12.5.4     Abnormal CIC group blocking procedures
       12.6     CIC group query (national use)
                 12.6.1     General
                 12.6.2     Interpretation of CIC states
       12.7     Support for Hard To Reach Network Management functions
                 12.7.1     SN/CMN initiating HTR indication
                 12.7.2     SN receiving HTR indication
       12.8     Automatic congestion control
                 12.8.1     Receipt of a release message containing an automatic congestion level parameter
                 12.8.2     Actions taken during overload
       12.9     Signalling transport out-of-service and in-service indications
      12.10     Signalling transport congestion indications
13     Abnormal conditions
       13.1     Introduction
       13.2     Dual seizure
                 13.2.1     Unguarded interval
                 13.2.2     Detection of dual seizure
                 13.2.3     Preventive action
                 13.2.4     Action to be taken on detection of dual seizures
       13.3     Reset of CICs
                 13.3.1     Reset CIC procedure
                 13.3.2     Group reset procedure
                 13.3.3     Abnormal group reset procedures
       13.4     Receipt of unreasonable signalling information
                 13.4.1     Handling of message format errors
                 13.4.2     Handling of unexpected messages
                 13.4.3     General requirements on receipt of unrecognized messages and parameters
                 13.4.4     Procedures for the handling of the unrecognized messages or parameters
                 13.4.5     Procedures for the handling of responses indicating unrecognized information has been sent
                 13.4.6     Procedures for handling unreasonable parameters
                 13.4.7     Handling of the BICC_Error indication primitive
                 13.4.8     Compatibility for the BICC APM user application
       13.5     Unequipped CIC message (national use)
       13.6     Overlength messages
       13.7     Timer expiries
                 13.7.1     Failure in the Reset CIC procedure
                 13.7.2     Failure in the Group Reset procedure
                 13.7.3     Failure in the blocking/unblocking sequence
                 13.7.4     Failure to receive a Release Complete message - Timer T1 and T5
                 13.7.5     Failure to receive a response to an information request message (national use)
Annex A – Timers
Annex B – Procedures for reuse of idle bearers (network option)
        B.1     Introduction
        B.2     Procedures
                  B.2.1     Outgoing bearer set-up procedures
                  B.2.2     Incoming bearer set-up procedures
                  B.2.3     Continuity message
                  B.2.4     Codec negotiation
                  B.2.5     Release procedure
Annex C – Test calls
        C.1     Called number for test calls
Annex D – Start-up procedures
        D.1     Introduction
        D.2     Procedure for putting CICs into service
        D.3     Test procedures
Annex E – (Network Option) Procedures for use of Structured AAL1 bearers
        E.1     Introduction
        E.2     Procedures
                  E.2.1     Codec negotiation
                  E.2.2     Release procedure
Appendix I – Message flow examples
        I.1     Introduction to message flows
        I.2     Contents
Appendix II – Generic BCF functions
       II.1     Introduction
       II.2     BNC-ID
                 II.2.1     BNC-ID usage during call and bearer set-up
                 II.2.2     BNC-ID usage for idle bearer reuse procedure (Network option)
                 II.2.3     BNC-ID usage for structured AAL1 bearers
       II.3     Bearer release control
       II.4     BIWF address
       II.5     BNC characteristics