• ITU-T Rec. X.225 (11/1988) – SESSION PROTOCOL SPECIFICATION FOR OPEN SYSTEMS INTERCONNECTION FOR CCITT APPLICATIONS
  • CONTENTS
  • 0 Introduction
  • 1 Scope and field of application
  • 2 References
  • 3 Definitions
  • 4 Symbols and abbreviations
    • 4.1 Data units
    • 4.2 SPDU fields
    • 4.3 Timer variables
    • 4.4 Miscellaneous
    • 4.5 Local variables
  • 5 Overview of the session protocol
    • 5.1 Model of the session layer
    • 5.2 Services provided by the session layer
    • 5.3 Services assumed from the transport layer
    • 5.4 Functions of the session layer
    • 5.5 Functional units
    • 5.6 Tokens
    • 5.7 Negotiation
    • 5.8 Local variables
  • 6 Use of the transport service
    • 6.1 Assignment of a session connection to the transport connection
    • 6.2 Reuse of the transport connection
    • 6.3 Use of transport normal data
    • 6.4 Use of transport expedited data
    • 6.5 Flow control
    • 6.6 Transport disconnection
  • 7 Elements of procedure related to SPDUs
    • 7.1 CONNECT SPDU
    • 7.2 OVERFLOW ACCEPT SPDU
    • 7.3 CONNECT DATA OVERFLOW SPDU
    • 7.4 ACCEPT SPDU
    • 7.5 REFUSE SPDU
    • 7.6 FINISH SPDU
    • 7.7 DISCONNECT SPDU
    • 7.8 NOT FINISHED SPDU
    • 7.9 ABORT SPDU
    • 7.10 ABORT ACCEPT SPDU
    • 7.11 DATA TRANSFER SPDU
    • 7.12 EXPEDITED SPDU
    • 7.13 TYPED DATA SPDU
    • 7.14 CAPABILITY DATA SPDU
    • 7.15 CAPABILITY DATA ACK SPDU
    • 7.16 GIVE TOKENS SPDU
    • 7.17 PLEASE TOKENS SPDU
    • 7.18 GIVE TOKENS CONFIRM SPDU
    • 7.19 GIVE TOKENS ACK SPDU
    • 7.20 MINOR SYNC POINT SPDU
    • 7.21 MINOR SYNC ACK SPDU
    • 7.22 MAJOR SYNC POINT SPDU
    • 7.23 MAJOR SYNC ACK SPDU
    • 7.24 RESYNCHRONIZE SPDU
    • 7.25 RESYNCHRONIZE ACK SPDU
    • 7.26 PREPARE SPDU
    • 7.27 EXCEPTION REPORT SPDU
    • 7.28 EXCEPTION DATA SPDU
    • 7.29 ACTIVITY START SPDU
    • 7.30 ACTIVITY RESUME SPDU
    • 7.31 ACTIVITY INTERRUPT SPDU
    • 7.32 ACTIVITY INTERRUPT ACK SPDU
    • 7.33 ACTIVITY DISCARD SPDU
    • 7.34 ACTIVITY DISCARD ACK SPDU
    • 7.35 ACTIVITY END SPDU
    • 7.36 ACTIVITY END ACK SPDU
    • 7.37 Additional elements of procedure for segmented SSDUs
  • 8 Structure and encoding of SPDUs
    • 8.1 TSDU structure
    • 8.2 SPDU structure
    • 8.3 SPDU identifiers and associated parameter fields
    • 8.4 Additional encoding rules for segmented SSDUs
  • 9 Conformance to this standard
  • ANNEX A – State tables
  • A.1 General
  • A.2 Notation for state tables
  • A.3 Conventions for entries in state tables
  • A.4 Actions to be taken by the SPM
  • A.5 Definitions of sets and variables
  • A.6 Notes to Tables A-7/X.225 to A-15/X.225:
  • ANNEX B – Relationship to CCITT Recommendation T.62 encoding
  • ANNEX C – PGIs and PIs reserved for use by Recommendation T.62
  • ANNEX D – Compatibility between protocol version 1 and protocol version 2
  • APPENDIX I – Differences between Recommendation X.225 and ISO International Standard 8327