IEC 62439-3:20 21规定了两种相关的冗余协议，在任何网络元件发生故障时，可提供零恢复时间的无缝切换: ？PRP（并行冗余协议），其允许将节点连接到两个单独的网络，同时允许仅将节点连接到一个网络；和 ？HSR（高可用性无缝冗余），允许对环形网络中的双端口节点或网状网络中的多端口节点进行线程处理。

IEC 62439-3:2021 specifies two related redundancy protocols that, in the event of failure of any network element, provide seamless switchover with zero recovery time:
？ PRP (Parallel Redundancy Protocol), which allows attaching nodes to two separate networks while allowing attachment of nodes to one network only; and
？ HSR (High-availability Seamless Redundancy), which allows threading two-port nodes in a ring or multi-port nodes in a meshed network.