International Standards Organization 6.14 Retention until acknowledgement of TPDUs 6.15 Resynchronization 6.16 Multiplexing and demultiplexing 6.17 Explicit flow control 6.18 Checksum 6.19 Frozen references 6.20 Retransmission on timeout 6.21 Resequencing 6.22 Inactivity control 6.23 Treatment of protocol errors 6.24 Splitting and recombining 7. Protocol Classes 7.0 Protocol description of class 0: simple class 7.1 Protocol description of class 1: basic error recovery class 7.2 Protocol description of class 2: multiplexing class 7.3 Protocol description of class 3: error recovery and multiplexing class 7.4 Protocol description of class 4: error detection and recovery class 8. Encoding 8.1 Summary 8.2 Structure 8.3 Connection Request (CR) 8.4 Connection Confirm (CC) 8.5 Disconnect Request (DR) 8.6 Disconnect Confirm (DC) 8.7 Data (DT 8.8 Expedited Data (ED) 8.9 Data Acknowledgement (AK) 8.10 Expedited Data Acknowledgement (EA) 8.11 Reject (RJ) 8.12 TPDU Error (ERR) Section Three - Conformance 9. Conformance 0. Introduction The Transport Protocol Standard is one of a set of International Standards produced to facilitate the interconection of computer systems. The set of standards covers the services and protocols required to achieve such interconnection. The Transport Protocol Standard is positioned with respect to other related standards by the layers defined in the Reference Model for Open Systems Interconnection (ISO 7498). It is most closely related to, and lies within the field of application of the Transport ISO Transport Protocol Specification