1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
5.1 Representation of octets
6 Introduction
7 Ring protection characteristics
7.1 Monitoring methods and conditions
7.2 Ethernet traffic and bandwidth consideration
7.3 Ethernet ring protection switching performance
8 Ring protection conditions and commands
9 Ring protection architectures
9.1 Revertive and non-revertive switching
9.2 Protection switching triggers
9.3 Protection switching models on a single Ethernet ring
9.4 Traffic channel blocking
9.5 R-APS channel blocking
9.6 FDB flush
9.7 Ethernet ring protection switching models for interconnection
10 Protection control protocol
10.1 Principles of operations
10.2 Protection switching behaviour
10.3 R-APS format
10.4 Failure of protocol defect
Appendix I – Ring protection network objectives
Appendix II – Ethernet ring network objectives
Appendix III – Ring protection scenarios
Appendix IV – Considerations for different timers
IV.1 State machine use of timers
IV.2 Guard timer use to block outdated R-APS messages
Appendix V – Interconnected rings example
V.1 Configuration for interconnected rings
V.2 Topology examples for interconnected Ethernet rings
Appendix VI – Protection switching for multiple ERP instances
VI.1 Multiple ERP instances
VI.2 Applying protection mechanisms to multiple ERP instances
VI.3 Protection switching model for multiple ERP instances
VI.4 Multiple instances of interconnected rings
Appendix VII – Guidelines for the configuration of VIDs and ring IDs of R-APS
channels
VII.1 Sub-ring with an R-APS virtual channel
VII.2 Sub-ring without an R-APS virtual channel
VII.3 Backward compatibility
Appendix VIII – Flush optimization
VIII.1 Flushing FDB consideration
VIII.2 Scenarios of unnecessary FDB flushing
VIII.3 Example of FDB flush optimization
VIII.4 Additional definition of the ERP control process model and
state machine
VIII.5 DNF status
Appendix IX – Guidelines for management procedures
IX.1 An example procedure for removing an Ethernet ring node
IX.2 Management procedures to exit the FS state in case of failure
of an Ethernet ring node under an FS condition
IX.3 Replacing an ITU-T G.8032 (2008) v1 Ethernet ring node with an
ITU‑T G.8032 (2010) v2 Ethernet ring node
Appendix X – Minimizing segmentation in interconnected rings
X.1 Characterization of the segmentation issue
X.2 Class of double faults addressed
X.3 Procedure for minimization of segmentation
Appendix XI – End-to-end service resilience
XI.1 Generic end-to-end service resilience
XI.2 Layering ITU-T G.8031 protection over ITU-T G.8032
XI.3 Access sub-ring connected to major ring
XI.4 Non-ERP node connected in a major ring
Bibliography