1
Scope
2 References
3 Definitions
4 Abbreviations
5 Protection characteristics
5.1 Monitoring methods and conditions
6 Protection group commands
6.1 End-to-end commands and states
6.2 Local commands
7 Protection architectures
7.1 Unidirectional and bidirectional
switching
7.2 Need for an APS/PCC channel
7.3 Revertive and non-revertive
switching
7.4 Provisioning mismatches
8 APS Protocol
8.1 APS channel format
8.2 Transmission and acceptance of APS
protocol
8.3 Request type
8.4 Protection types
8.5 Requested signal
8.6 Bridged signal
8.7 Control of bridge
8.8 Control of selector
8.9 Signal Fail of the protection
entity
8.10 Equal Priority Requests
8.11 Command Acceptance and Retention
8.12 Hold-off timer
8.13 Exercise operation
8.14 APS channel alarming
Appendix I – Examples
of operation
I.1 1+1 Unidirectional switching
I.2 1+1 Bidirectional switching
I.3 1:n Bidirectional switching
I.4 Exercise command operation