Interlogix NS3550-2T-8S User Manual - Manual (Page 338)

IFS NS3552-8P-2S AND NS3550-2T-8S User Manual
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4.19 Ring
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.