Users Guide

1034 Ethernet Ring Protection
Figure 26-1. Ethernet Ring Protection
The ring protection architecture uses the R-APS protocol to coordinate ring
protection actions within an Ethernet ring. When a failure is detected on a
ring port, the node detecting the failure will generate an R-APS Signal Fail
(SF) message along both the directions. This message notifies the other ring
nodes of the failure and causes a protection switch to occur. The RPL nodes
(owner and neighbor) unblock the RPL link.
When the failed link is restored, the nodes adjacent to the restored link send
R-APS No Request (NR) messages. Upon receiving this message, the RPL
owner blocks the RPL port and sends an R-APS No Request, RPL blocked
(NR, RB) message. This will cause all nodes other than RPL owner in the ring
to unblock all blocked ports.
Ethernet Ring Protection supports the following topologies:
• Single ring
• Shared ring node: A single node would participate in two physical rings and
bridge between them.
• Multi-ring (sub-ring without R-APS virtual channel)