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