ITU-T G.8031 PDF

This Recommendation defines the APS protocol and linear protection switching mechanisms for point-to-point VLAN-based ETH subnetwork connection (SNC) in Ethernet transport networks. All other protection schemes, including point-to-multipoint and multipoint-to-multipoint, are for further study.

Linear 1+1 and 1:1 protection switching architectures with unidirectional and bidirectional switching are defined in this version of the Recommendation.

The APS protocol and protection switching operation for all other Ethernet network architectures, (for example, ring, mesh, etc.), are for further study.