Users Guide

1036 Ethernet Ring Protection
to the ERP control process for local processing and also forward the received
R-APS to the next node if the next hop port is not blocked. When a node
receives its own generated R-APS message, it drops the R-APS message.
The node that actually generates the R-APS messages will always send
messages over both of its ring ports regardless of whether or not the R-APS
channels are blocked on its ring ports. Similarly, R-APS messages will be
received and processed regardless of whether or not the R-APS channel is
being blocked on its ring ports.
Traffic Channel
Each Ethernet Ring Protection (ERP) instance is responsible for protecting
one or more VLANs (known as traffic channels) that transport traffic over the
physical ring. All the nodes in the ring are required to have the same
protected VLANs. The traffic channel should have the ERP ring ports as
members.
Each traffic channel and each R-APS channel on the ring port are managed by
the Ethernet Ring Protection control process (ERP control process) of only
one Ethernet ring. The R-APS channel and traffic channel must be mapped
to an ERP instance.
Ring Scope
A ring may be configured per port or per VLAN. In a per port ring, there is
only one instance and, by default, all the VLANs that are participating in both
the ring ports are protected. In the per VLAN ring, multiple instances may be
configured and the administrator can define the protected VLANs for each
instance.
Ethernet Ring Protection Port Status
On an ERP ring, a ring port has a status of:
• Forwarding (unblocked): forwards data traffic and transmits and receives
R-APS PDUs.
• Discarding (blocked): only transmits and receives R-APS PDUs.