CONTENTS

SECTION  1  –  GENERAL
 1     Scope
 2     Normative references
        2.1     Identical Recommendations | International Standards
        2.2     Paired Recommendations | International Standards equivalent in technical content
        2.3     Additional References
 3     Definitions
        3.4     Session protocol definitions
 4     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     Protocol version numbers
        5.6     Functional units
        5.7     Tokens
        5.8     Negotiation
        5.9     Local variables
SECTION  2  –  SESSION  PROTOCOL  SPECIFICATION
 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
                 7.11.1     Content of DATA TRANSFER SPDU
                 7.11.2     Sending the DATA TRANSFER SPDU
                 7.11.3     Receiving the DATA TRANSFER SPDU
       7.12     EXPEDITED SPDU
                 7.12.1     Content of EXPEDITED SPDU
                 7.12.2     Sending the EXPEDITED SPDU
                 7.12.3     Receiving the EXPEDITED SPDU
       7.13     TYPED DATA SPDU
                 7.13.1     Content of TYPED DATA SPDU
                 7.13.2     Sending the TYPED DATA SPDU
                 7.13.3     Receiving the TYPED DATA SPDU
       7.14     CAPABILITY DATA SPDU
                 7.14.1     Content of CAPABILITY DATA SPDU
                 7.14.2     Sending the CAPABILITY DATA SPDU
                 7.14.3     Receiving the CAPABILITY DATA SPDU
       7.15     CAPABILITY DATA ACK SPDU
                 7.15.1     Content of CAPABILITY DATA ACK SPDU
                 7.15.2     Sending the CAPABILITY DATA ACK SPDU
                 7.15.3     Receiving the CAPABILITY DATA ACK SPDU
       7.16     GIVE TOKENS SPDU
                 7.16.1     Content of GIVE TOKENS SPDU
                 7.16.2     Sending the GIVE TOKENS SPDU
                 7.16.3     Receiving the GIVE TOKENS SPDU
       7.17     PLEASE TOKENS SPDU
                 7.17.1     Content of PLEASE TOKENS SPDU
                 7.17.2     Sending the PLEASE TOKENS SPDU
                 7.17.3     Receiving the PLEASE TOKENS SPDU
       7.18     GIVE TOKENS CONFIRM SPDU
                 7.18.1     Content of GIVE TOKENS CONFIRM SPDU
                 7.18.2     Sending the GIVE TOKENS CONFIRM SPDU
                 7.18.3     Receiving the GIVE TOKENS CONFIRM SPDU
       7.19     GIVE TOKENS ACK SPDU
                 7.19.1     Content of GIVE TOKENS ACK SPDU
                 7.19.2     Sending the GIVE TOKENS ACK SPDU
                 7.19.3     Receiving the GIVE TOKENS ACK SPDU
       7.20     MINOR SYNC POINT SPDU
                 7.20.1     Content of MINOR SYNC POINT SPDU
                 7.20.2     Sending the MINOR SYNC POINT SPDU
                 7.20.3     Receiving the MINOR SYNC POINT SPDU
       7.21     MINOR SYNC ACK SPDU
                 7.21.1     Content of MINOR SYNC ACK SPDU
                 7.21.2     Sending the MINOR SYNC ACK SPDU
                 7.21.3     Receiving the MINOR SYNC ACK SPDU
       7.22     MAJOR SYNC POINT SPDU
                 7.22.1     Content of MAJOR SYNC POINT SPDU
                 7.22.2     Sending the MAJOR SYNC POINT SPDU
                 7.22.3     Receiving the MAJOR SYNC POINT SPDU
       7.23     MAJOR SYNC ACK SPDU
                 7.23.1     Content of MAJOR SYNC ACK SPDU
                 7.23.2     Sending the MAJOR SYNC ACK SPDU
                 7.23.3     Receiving the MAJOR SYNC ACK SPDU
       7.24     RESYNCHRONIZE SPDU
                 7.24.1     Content of RESYNCHRONIZE SPDU
                 7.24.2     Sending/receiving the RESYNCHRONIZE SPDU without symmetric synchronization
                              7.24.2.1     Sending the RESYNCHRONIZE SPDU without symmetric synchronization
                              7.24.2.2     Receiving the RESYNCHRONIZE SPDU without symmetric synchronization
                              7.24.2.3     Resynchronization contention without symmetric synchronization
                 7.24.3     Sending/receiving the RESYNCHRONIZE SPDU with symmetric synchronization
                              7.24.3.1     Sending the RESYNCHRONIZE SPDU with symmetric synchronization
                              7.24.3.2     Receiving the RESYNCHRONIZE SPDU with symmetric synchronization
                              7.24.3.3     Resynchronization contention with symmetric synchronization
       7.25     RESYNCHRONIZE ACK SPDU
                 7.25.1     Content of RESYNCHRONIZE ACK SPDU
                 7.25.2     Sending/receiving the RESYNCHRONIZE ACK SPDU without symmetric synchronization
                              7.25.2.1     Sending the RESYNCHRONIZE ACK SPDU without symmetric synchronization
                              7.25.2.2     Receiving the RESYNCHRONIZE ACK SPDU without symmetric synchronization
                 7.25.3     Sending/receiving the RESYNCHRONIZE ACK SPDU with symmetric synchronization
                              7.25.3.1     Sending the RESYNCHRONIZE ACK SPDU with symmetric synchronization
                              7.25.3.2     Receiving the RESYNCHRONIZE ACK SPDU with symmetric synchronization
       7.26     PREPARE SPDU
                 7.26.1     Content of PREPARE SPDU
                 7.26.2     Sending the PREPARE SPDU
                 7.26.3     Receiving the PREPARE SPDU
       7.27     EXCEPTION REPORT SPDU
                 7.27.1     Content of EXCEPTION REPORT SPDU
                 7.27.2     Sending the EXCEPTION REPORT SPDU
                 7.27.3     Receiving the EXCEPTION REPORT SPDU
       7.28     EXCEPTION DATA SPDU
                 7.28.1     Content of EXCEPTION DATA SPDU
                 7.28.2     Sending the EXCEPTION DATA SPDU
                 7.28.3     Receiving the EXCEPTION DATA SPDU
       7.29     ACTIVITY START SPDU
                 7.29.1     Content of ACTIVITY START SPDU
                 7.29.2     Sending the ACTIVITY START SPDU
                 7.29.3     Receiving the ACTIVITY START SPDU
       7.30     ACTIVITY RESUME SPDU
                 7.30.1     Content of ACTIVITY RESUME SPDU
                 7.30.2     Sending the ACTIVITY RESUME SPDU
                 7.30.3     Receiving the ACTIVITY RESUME SPDU
       7.31     ACTIVITY INTERRUPT SPDU
                 7.31.1     Content of ACTIVITY INTERRUPT SPDU
                 7.31.2     Sending the ACTIVITY INTERRUPT SPDU
                 7.31.3     Receiving the ACTIVITY INTERRUPT SPDU
       7.32     ACTIVITY INTERRUPT ACK SPDU
                 7.32.1     Content of ACTIVITY INTERRUPT ACK SPDU
                 7.32.2     Sending the ACTIVITY INTERRUPT ACK SPDU
                 7.32.3     Receiving the ACTIVITY INTERRUPT ACK SPDU
       7.33     ACTIVITY DISCARD SPDU
                 7.33.1     Content of ACTIVITY DISCARD SPDU
                 7.33.2     Sending the ACTIVITY DISCARD SPDU
                 7.33.3     Receiving the ACTIVITY DISCARD SPDU
       7.34     ACTIVITY DISCARD ACK SPDU
                 7.34.1     Content of ACTIVITY DISCARD ACK SPDU
                 7.34.2     Sending the ACTIVITY DISCARD ACK SPDU
                 7.34.3     Receiving the ACTIVITY DISCARD ACK SPDU
       7.35     ACTIVITY END SPDU
                 7.35.1     Content of ACTIVITY END SPDU
                 7.35.2     Sending the ACTIVITY END SPDU
                 7.35.3     Receiving the ACTIVITY END SPDU
       7.36     ACTIVITY END ACK SPDU
                 7.36.1     Content of ACTIVITY END ACK SPDU
                 7.36.2     Sending the ACTIVITY END ACK SPDU
                 7.36.3     Receiving the ACTIVITY END ACK SPDU
       7.37     Additional Elements of Procedure for Segmented SSDUs
                 7.37.1     Content of the SPDU
                 7.37.2     Sending the SPDU
                 7.37.3     Receiving the SPDU
 8     Structure and encoding of SPDUs
        8.1     TSDU structure
        8.2     SPDU structure
                  8.2.1     SPDUs     
                  8.2.2     PGI units
                  8.2.3     PI units     
                  8.2.4     Identifier fields
                  8.2.5     Length indicator field
                  8.2.6     Parameter fields
                  8.2.7     Parameter values
                  8.2.8     User information fields
        8.3     SPDU identifiers and associated parameter fields
                  8.3.1     CONNECT (CN) SPDU
                  8.3.2     OVERFLOW ACCEPT (OA) SPDU
                  8.3.3     CONNECT DATA OVERFLOW (CDO) SPDU
                  8.3.4     ACCEPT (AC) SPDU
                  8.3.5     REFUSE (RF) SPDU
                  8.3.6     FINISH (FN) SPDU
                  8.3.7     DISCONNECT (DN) SPDU
                  8.3.8     NOT FINISHED (NF) SPDU
                  8.3.9     ABORT (AB) SPDU
                 8.3.10     ABORT ACCEPT (AA) SPDU
                 8.3.11     DATA TRANSFER (DT) SPDU
                 8.3.12     EXPEDITED (EX) SPDU
                 8.3.13     TYPED DATA (TD) SPDU
                 8.3.14     CAPABILITY DATA (CD) SPDU
                 8.3.15     CAPABILITY DATA ACK (CDA) SPDU
                 8.3.16     GIVE TOKENS (GT) SPDU
                 8.3.17     PLEASE TOKENS (PT) SPDU
                 8.3.18     GIVE TOKENS CONFIRM (GTC) SPDU
                 8.3.19     GIVE TOKENS ACK (GTA) SPDU
                 8.3.20     MINOR SYNC POINT (MIP) SPDU
                 8.3.21     MINOR SYNC ACK (MIA) SPDU
                 8.3.22     MAJOR SYNC POINT (MAP) SPDU
                 8.3.23     MAJOR SYNC ACK (MAA) SPDU
                 8.3.24     RESYNCHRONIZE (RS) SPDU
                 8.3.25     RESYNCHRONIZE ACK (RA) SPDU
                 8.3.26     PREPARE (PR) SPDU
                 8.3.27     EXCEPTION REPORT (ER) SPDU
                 8.3.28     EXCEPTION DATA (ED) SPDU
                 8.3.29     ACTIVITY START (AS) SPDU
                 8.3.30     ACTIVITY RESUME (AR) SPDU
                 8.3.31     ACTIVITY INTERRUPT (AI) SPDU
                 8.3.32     ACTIVITY INTERRUPT ACK (AIA) SPDU
                 8.3.33     ACTIVITY DISCARD (AD) SPDU
                 8.3.34     ACTIVITY DISCARD ACK (ADA) SPDU
                 8.3.35     ACTIVITY END (AE) SPDU
                 8.3.36     ACTIVITY END ACK (AEA) SPDU
        8.4     Additional encoding rules for segmented SSDUs
                  8.4.1     First SPDU in sequence
                  8.4.2     Subsequent SPDUs in a sequence
SECTION  3  –  CONFORMANCE
 9     Conformance to this Recommendation | International Standard
        9.1     Static conformance requirements
        9.2     Dynamic conformance requirements
        9.3     Protocol Implementation Conformance Statement
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.4.1     Invalid intersections
                  A.4.2     Valid intersections
                  A.4.3     Receipt of SPDUs
        A.5     Definitions of sets and variables
                  A.5.1     Functional units
                  A.5.2     Tokens
                  A.5.3     SET of tokens
                  A.5.4     Variables
                               A.5.4.1     TEXP
                               A.5.4.2     Vact
                               A.5.4.3     Vnextact
                               A.5.4.4     Vrsp and Vrspnb
                               A.5.4.5     Vrsps, Vrspr, Vspnbs, and Vrspnbr
                               A.5.4.6     SPMwinner
                               A.5.4.7     Vtca
                               A.5.4.8     Vtrr
                               A.5.4.9     Vcoll
                              A.5.4.10     Vdnr
                              A.5.4.11     V(A)
                              A.5.4.12     V(M)
                              A.5.4.13     V(R)
                              A.5.4.14     Vsc
                              A.5.4.15     V(Ado)
                              A.5.4.16     V(Adi)
                              A.5.4.17     V(As), V(Ar)
                              A.5.4.18     V(Ms), V(Mr)
                              A.5.4.19     V(Rs), V(Rr)
                              A.5.4.20     Discard-rcv-flow – Discard-snd-flow
Annex B – PGIs and PIs reserved for use by Recommendation T.62
Annex C – Relationship to Recommendation T.62 encoding
Annex D – Differences between Protocol Version 1 and Protocol Version 2