scope:

This Recommendation defines the automatic protection switching (APS) protocol and protection switching mechanisms for ETH layer Ethernet ring topologies. The protection protocol defined in this Recommendation enables protected point-to-point, point-to-multipoint and multipoint-tomultipoint connectivity within the ring or interconnected rings, called "multi-ring/ladder network" topology.

The ETH layer ring maps to physical layer ring structure.

Protection schemes for the other layers, including ETY layer, are out of scope of this Recommendation.