2     References
 3     Terms and definitions
 4     Abbreviations
 5     Protection classifications
 6     Applications considerations
        6.1     MS shared protection rings
        6.2     MS shared protection rings (transoceanic application)
        6.3     MS dedicated protection rings
        6.4     Unidirectional and bidirectional protection switching
        6.5     Linear VC trail protection
        6.6     Subnetwork connection protection
        6.7     Linear multiplex section protection switching
 7     SDH trail protection
        7.1     Linear multiplex section protection
                  7.1.1     MSP protocol
                  7.1.2     MSP commands
                  7.1.3     MSP conditions
                  7.1.4     Switch operation
        7.2     MS shared protection rings
                  7.2.1     Two- and four-fibre MS shared protection rings
                  7.2.2     Network objectives
                  7.2.3     Application architecture
                  7.2.4     Switch initiation criteria
                  7.2.5     Protection switch protocol
                  7.2.6     Protection algorithm operation
                  7.2.7     Examples
        7.3     MS dedicated protection rings
        7.4     Linear VC trail protection
                  7.4.1     Network architecture
                  7.4.2     Network objectives
                  7.4.3     Application architecture
                  7.4.4     Switch initiation criteria
                  7.4.5     Protection switching protocol
                  7.4.6     Protection algorithm operation
 8     SDH subnetwork connection protection
        8.1     Network architecture
        8.2     Network objectives
        8.3     Application architecture
                  8.3.1     Routing
                  8.3.2     1 + 1 unidirectional protection switching
                  8.3.3     Other architectures
        8.4     Switch initiation criteria
                  8.4.1     1 + 1 unidirectional protection switching
                  8.4.2     Other architectures
        8.5     Protection switching protocol
                  8.5.1     1 + 1 unidirectional protection switching
                  8.5.2     Other architectures
        8.6     Protection algorithm operation
                  8.6.1     1 + 1 unidirectional protection switching algorithm
                  8.6.2     Other architectures
Annex A – MS shared protection rings (transoceanic application)
        A.1     Application
        A.2     Network objectives
        A.3     Application architecture
        A.4     Switching criteria
        A.5     Protection switch protocol
        A.6     Protection algorithm operation
Annex B – Multiplex section protection (MSP) 1 + 1 optimized protocol, commands and operation
        B.1     1 + 1 bidirectional switching optimized for a network using predominantly 1 + 1 bidirectional switching
                  B.1.1     Lockout
                  B.1.2     Secondary section failure
                  B.1.3     K1/K2 byte coding
                  B.1.4     K2 byte coding
                  B.1.5     Primary section mismatch
        B.2     Switch commands
        B.3     Switch operation
Appendix I – Examples of protection switching in an MS shared protection ring
        I.1     Unidirectional signal fail (span) in a four-fibre ring
        I.2     Unidirectional signal fail (ring)
        I.3     Bidirectional signal fail (ring)
        I.4     Unidirectional signal degrade (ring)
        I.5     Node failure
        I.6     Unidirectional SF-R pre-empting a unidirectional SD-S on non-adjacent spans
        I.7     Unidirectional SF-S pre-empting a unidirectional SF-R on adjacent spans – SF-S and SF-R detected at non-adjacent nodes
        I.8     Unidirectional SF-R pre-empting a unidirectional SD-S on adjacent spans
        I.9     Unidirectional SF-R coexisting with a unidirectional SF-R on non-adjacent spans
       I.10     Node failure on a ring with extra traffic capability (see Figure I.11)
       I.11     Unidirectional SF-S pre-empting a unidirectional SF-R on adjacent spans – SF-S and SF-R detected at adjacent nodes
Appendix II – Generalized squelching logic
       II.1     Squelching for unidirectional (and bidirectional) circuits
       II.2     Squelching of multiply dropped and multiply sourced unidirectional circuits
                 II.2.1     Multiply dropped unidirectional circuits
                 II.2.2     Multiply sourced unidirectional circuits
                 II.2.3     Application to ring interworking