Ethernet ring protection switching (Eth-ring) provides ITU-T G.8032 specification compliance to achieve resiliency for Ethernet Layer 2 networks. Similar to G.8031 linear protection (also called Automatic Protection Switching (APS)), G.8032 Eth-ring is implemented on Ethernet OAM and often referred to as Ring Automatic Protection Switching (R-APS).
Eth-rings are supported on VPLS SAPs. VPLS services supporting Rings SAPs can connect to other rings and Ethernet service using VPLS, and R-VPLS SAPs. The Eth-ring service enables rings for core network or access network resiliency. A single point of interconnection to other services is supported. The Eth-ring service is a VLAN service providing protection for ring topologies and the ability to interact with other protection mechanisms for overall service protection. This ensures failures detected by Eth-ring only result in R-APS switchover when the lower layer cannot recover, and that higher layers are isolated from the failure.
Rings are preferred in data networks where the native connectivity is laid out in a ring or there is a requirement for simple resilient LAN services. Because of the symmetry and the simple topology, rings are viewed a good solution for access and core networks where resilient LANS are required. The Nokia implementation of G.8032 Eth-ring can be used for interconnecting access rings and to provide traffic engineered backbone rings. The 7210 SAS implementation of G.8032 Eth-ring supports dual interconnected rings with sub-rings.
Eth-rings use one VID per control per ring instance and use one (typically) or multiple VIDs for data instances per control instance. A dedicated control VLAN (ERP VLAN) is used to run the protocol on the control VID. G.8032 controls the active state for the data VLANs (ring data instances) associated with a control instance. Multiple control instances allow logically separate rings on the same topology. The Nokia implementation supports dot1q, and QinQ encapsulation for data ring instances. The control channel supports dot1q and QinQ encapsulation.