节点包括两个或更多个环网被连接成环形，进行了ERP对于每个环网，所述环形网络作为用于在共享链路检测的故障的主环中的一个，其他子环网 用于环的通信系统中，共享节点终止所述共享链路检测各环形网络的两个或多个环的网络共享公用链路的故障，检测到在共享链路故障的故障 监视单元311，基于故障，用于确定环网内的交换处理单元312的检测结果是一个主环，当由切换单元312，在切换到R-APS帧之后的识别信息进行切换 商店包括ERP处理单元22-1和22-2用于传送或发送帧。

Node comprises two or more ring networks connected in a ring form, implement ERP for each ring network, one of the ring network and the measuring of detecting a failure in the shared link, the sub other ring network a communication system for the ring, shared nodes terminating the shared link detects a failure in each of the ring network for two or more of the ring network that share a common link, detect a failure in the shared link failure a monitoring unit 311, based on the detection result of the failure, the switching processor 312 which determines the ring network to the measuring, when the switching is performed by the switching processing unit 312, the identification information after switching to R-APS frame store includes an ERP processing units 22-1 and 22-2 to transfer or transmit the frame, the.