User's Manual

User’s Manual of SGS-5240 Series Managed Switch
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4.2.17 ERPS
ITU-T G.8032 Ethernet Ring protection switching (ERPS) is a link layer protocol applied on Ethernet loop protection to
provide sub-50ms protection and recovery switching for Ethernet traffic in a ring topology.
ERPS provides a faster redundant recovery than Spanning Tree topology. The action is similar to STP or RSTP, but the
algorithms between them are not the same. In the Ring topology, every switch should be enabled with Ring function and two
ports should be assigned as the member ports in the ERPS. Only one switch in the Ring group would be set as the RPL owner
switch that one port would be blocked, called owner port, and PRL neighbor switch has one port that one port would be blocked,
called neighbor port that connect to owner port directly and this link is called the Ring Protection Link or RPL. Each switch
will sends ETH-CCM message to check the link status in the ring group. When the failure of network connection occurs, the
nodes block the failed link and report the signal failure message, the RPL owner switch will automatically unblocks the PRL to
recover from the failure.