Several typical network redundancy techniques stipulated in IEC62439 standards are introduced: CRP (Cross-network Redundancy Protocol ),DRP( Distributed Redundancy Protocol), MRP (Media Redundancy Protocol ),BRP( Beacon Redundancy Protocol) ,PRP( Parallel Redundancy Protocol) and HSR (High-availability Seamless Ring). CRP supports mono-/dual-network redundancy, connecting with one/two independent networks via two ports. DRP is based on the ring topology and implemented in switch. MRP recovers the communication of ring network within a defined time when a single failure occurs in link or switch. BRP redundant network is composed of two interconnected top switches, each linking a star/line/ring subnet. PRP realizes the dual sending and receiving of message at LRE in end node. HSR network consists of the switching end nodes arranged in a ring,each having two ports. Comparison shows that,PRP/HSR is the. Ideal solution of network redundancy in applicability,adaptability and failure recovery.%介绍了IEC62439标准中的几种典型的网络冗余技术,包括跨网冗余协议(CRP)、分布冗余协议(DRP)、媒介冗余协议(MRP)、信标冗余协议(BRP)、并行冗余协议(PRP)和高可用性无缝冗余协议(HSR).CRP支持单网和双网冗余,通过2个端口跨接到1个或2个独立的网络中实现冗余.DRP是基于环网拓扑的冗余模式,在交换设备上实现.MRP可以在网络连接或是交换设备单点故障的时候以确定性时间恢复环网通信.BRP冗余网络架构可以看成2个互连的顶层交换机,各级连一个星形、线形或是环形子网.PRP在终端节点内的LRE层实现了报文的双发、双收.经过比较,指出PRP/HSR方案不论是在应用方面或网络冗余的适应性以及对故障的恢复性能方面,都是理想的通信网络的冗余方案.
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