Rec. ITU-T X.224 (11/1993) PROTOCOL FOR PROVIDING THE OSI CONNECTION-MODE TRANSPORT SERVICE
FOREWORD
ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS AND OPEN SYSTEM COMMUNICATIONS
CONTENTS
SUMMARY
Introduction
1 Scope
2 References
    2.1 Identical Recommendations | International Standards
    2.2 Paired Recommendations | International Standards equivalent in technical content
3 Definitions
4 Abbreviations
    4.1 Data units
    4.2 Types of Transport Protocol data units
    4.3 TPDU Fields
    4.4 Times and associated variables
    4.5 Miscellaneous
5 Overview of the Transport Protocol
    5.1 Service provided by the Transport Layer
    5.2 Service assumed from the Network Layer
    5.3 Functions of the Transport Layer
    5.4 Classes and options when operating over CONS
    5.5 Characteristics of class 4 transport protocol when operating over CLNS
    5.6 Model of the Transport Layer
6 Elements of procedure
    6.1 Use of the network service
    6.2 Transport protocol data unit (TPDU) transfer
    6.3 Segmenting and reassembling
    6.4 Concatenation and separation
    6.5 Connection establishment
    6.6 Connection refusal
    6.7 Normal release
    6.8 Error release when operating over CONS
    6.9 Association of TPDUs with transport connections
    6.10 Data TPDU numbering
    6.11 Expedited data transfer
    6.12 Reassignment after failure when operating over CONS
    6.13 Retention and acknowledgement of TPDUs
7 Protocol classes
8 Specification for class 0: Simple class
    8.1 Functions of class 0
    8.2 Procedures for class 0
9 Specification for class 1: Basic error recovery class
    9.1 Functions of class 1
    9.2 Procedures for class 1
10 Specification for class 2: Multiplexing class
    10.1 Functions of class 2
    10.2 Procedures for class 2
11 Specification for class 3: Error recovery and multiplexing class
    11.1 Functions of class 3
    11.2 Procedures for class 3
12 Specification for class 4: Error detection and recovery class
    12.1 Functions of class 4
    12.2 Procedures for class 4
13 Structure and encoding of TPDUs
    13.1 Validity
    13.2 Structure
    13.3 Connection request (CR) TPDU
    13.4 Connection Confirm (CC) TPDU
    13.5 Disconnect Request (DR) TPDU
    13.6 Disconnect Confirm (DC) TPDU
    13.7 Data (DT) TPDU
    13.8 Expedited data (ED) TPDU
    13.9 Data acknowledgement (AK) TPDU
    13.10 Expedited data acknowledgement (EA) TPDU
    13.11 Reject (RJ) TPDU
    13.12 TPDU error (ER) TPDU
14 Conformance
Annex A (normative) State tables
A.1 General
A.2 Conventions
A.3 Tables
A.4 State tables for classes 0 and 2
A.5 State tables for classes 1 and 3
A.6 State tables for class 4 over CONS
A.7 State tables for class 4 over CLNS
Annex B (normative) Network connection management subprotocol
B.1 Introduction
B.2 Scope
B.3 Definitions
B.4 Abbreviations
B.5 Overview of the protocol
B.6 Elements of procedure
B.7 Protocol operation
B.8 Structure and encoding of TPDUs
B.9 Conformance
B.10 State Table
B.11 Diagram for NCMS protocol operation
Annex C (normative) PICS Proforma
C.1 General
C.2 Identification
C.3 Indices used in this annex
C.4 Based standard/recommendation conformance
C.5 General statement of conformance
C.6 Protocol implementation
C.7 NCMS functions
C.8 Initiator/responder capability for protocol classes 0 - 4
C.9 Supported functions
C.10 Supported TPDUs
C.11 Supported parameters of issued TPDUs
C.12 Supported parameters for received TPDUs
C.13 User data in issued TPDUs
C.14 User data in received TPDUs
C.15 Negotiation
C.16 Error handling
C.17 Timers and protocol parameters
Annex D (informative) Checksum Algorithms
D.1 Symbols
D.2 Arithmetic conventions
D.3 Algorithm for generating checksum parameters
D.4 Algorithm for checking checksum parameters
Annex E (informative) State tables for operation of class 4 over connection-mode and connectionless-mode ...
E.1 General
E.2 Conventions
E.3 Tables
E.4 State tables for Class 4
Appendix I Differences between Recommendation X.224 and ISO/IEC 8073:1992
I.1 Assignment to network connections
I.2 Conformance
I.3 Class negotiation
I.4 Precedence
I.5 Difference between Recommendation X.224 and ISO/IEC 8073