CONTENTS

 1     Scope
 2     References
 3     Terms and definitions
 4     Abbreviations
 5     Convention
 6     Description of services
        6.1     General
        6.2     Service parameters
 7     Architecture of the protocol
        7.1     Service provided by the underlying layer
        7.2     Link Flow Control
        7.3     Link set-up
        7.4     Link acknowledgement
        7.5     Multiplexing
        7.6     VC sequence and retransmission control
        7.7     VC-flow control
        7.8     VC segmentation and reassembly
        7.9     VC signalling
 8     Description of the DTE/DCE interface (physical layer)
 9     Coding of frames and packets
        9.1     General
        9.2     Description of frames
        9.3     Description of packets
        9.4     Meaning of the frame and packet fields
        9.5     Coding of the Type field
10     Link and VC-level procedures
       10.1     Identification of the link connection
       10.2     Generic status request procedure
       10.3     Future upgrades with upward compatibility
       10.4     Segment definition
       10.5     Flow control at the link layer
       10.6     Link set-up and disconnection
       10.7     Procedure for positive and negative acknowledgements of PDU
       10.8     Error correction
       10.9     Multiplexing / demultiplexing
      10.10     Numbering of packets at the VC layer
      10.11     Re-ordering of data packets
      10.12     Flow control at the VC layer
      10.13     Data transfer
      10.14     Interrupt procedure
      10.15     Reset of a virtual circuit
11     Signalling coding
       11.1     Message functional definitions and contents
       11.2     General message format and information elements coding
       11.3     Addressing
       11.4     Handling of coding errors
12     Procedures for permanent virtual circuit service
13     Signalling procedures for switched virtual circuits
       13.1     Set-up and clearing procedures
       13.2     Procedure for restart
       13.3     Effects of clearing and restart procedures on transfer of packets
14     Procedures for user facilities
       14.1     Incoming calls barred
       14.2     Outgoing calls barred
       14.3     Packet size negotiation facility
       14.4     Assured / non-assured data transfer negotiation facility
       14.5     Throughput negotiation facilities
       14.6     Closed user group related facilities
       14.7     Fast select
       14.8     Reverse charging
       14.9     Reverse charging acceptance
      14.10     Local charging prevention
      14.11     Network User Identification (NUI) related facilities
      14.12     Transit network selection related facilities
      14.13     Hunt group
      14.14     Call redirection and call deflection related facilities
      14.15     Called line address modified notification
      14.16     Transit delay selection and indication
      14.17     Alternative addressing facilities
Annex A – Additional information for interworking between X.25 and X.45 protocols
        A.1     Throughput mapping
        A.2     Data transfer option
        A.3     Signalling coding mapping
Appendix I – Subscription parameters
        I.1     Subscription parameters per interface
        I.2     Subscription parameters per PVC