ITU-T Rec. X.224 (11/1988) – TRANSPORT 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 Types of transport protocol data unit
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
5.5 Model of the transport layer
6 Elements of procedure
6.1 Assignment to network connection
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
6.9 Association of TPDUs with transport connections
6.10 Data TPDU numbering
6.11 Expedited data transfer
6.12 Reassignment after failure
6.13 Retention until acknowledgment of TPDUs
6.14 Resynchronization
6.15 Multiplexing and demultiplexing
6.16 Explicit flow control
6.17 Checksum
6.18 Frozen references
6.19 Retransmission on timeout
6.20 Resequencing
6.21 Inactivity control
6.22 Treatment of protocol errors
6.23 Splitting and recombining
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 acknowledgment (EA)
13.11 Reject (RJ) TPDU
13.12 TPDU error (ER) TPDU
14 Conformance
ANNEX A – State tables
A.1 Conventions
A.2 General
A.3 State tables for Classes 0 and 2
A.4 State tables for Classes 1 and 3
A.5 State tables for Class 4
ANNEX B – Transport protocol identification
B.1 Introduction
B.2 Conveyance of PI TPDU
B.3 Encoding of the PI TPDU
APPENDIX I – Checksum algorithms
I.1 Symbols
I.2 Arithmetic conventions
I.3 Algorithm for generating checksum parameters
I.4 Algorithm for checking checksum parameters
APPENDIX II – Differences between Recommendation X.224 and ISO 8073 (1986)
II.1 Defect reports
II.2 Conformance
II.3 Class negotiation
II.4 Precedence
II.5 Assignment to network connections
II.6 Transport protocol identification
II.7 Checksum algorithms