Antaira Industrial Ethernet Switches
LMP-0501 Series User Manual V1.0
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Ethernet Ring Protection Switching (ERPS)
, defined in ITU-T G8032, implements a protection
switching mechanism for Ethernet traffic in a ring topology. By performing the ERPS function,
potential loops in a network can be avoided by blocking traffic to flow to the ring protection link
(RPL) to protect the entire Ethernet ring.
In a network with ring topology that runs ERPS, only one switch is assigned as an
“owner” that is
responsible for blocking traffic in RPL so as to avoid loops. The switch adjacent to the RPL owner
is called the RPL “neighbor” node that is responsible for blocking its end of the RPL under normal
condition. Other participating switches adjacent to the RPL owner or neighbor in a ring are
members or RPL next-neighbor nodes to this topology and normally forward receive traffic.
ERPS, like STP, provides a loop-free network by using polling packets to detect faults. When a
fault occurs, ERPS heals itself by sending traffic over a protected reverse path less than 50ms
and recover quickly to forward traffic. Because of this fault detection mechanism, the network
broadcast storm problem could be avoided as well.
5.5.1 ERPS Status
Below,
Figure 5.18,
shows the network redundancy ring status with the Ethernet Ring Protection
Switch (ERPS) protocol.
Figure 5.18
– Redundant Ring Network – ERPS Status
