Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 542)

512 Multi-Service IronWare Switching Configuration Guide
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Ethernet Ring Protection
15
NOTE
Before configuring ERP, you must configure a VLAN and the ports you require for your deployment.
This chapter describes ERP components, features, and how to configure, and manage ERP.
Ethernet Ring Protection components
An ERP deployment consists of the following components:
• Roles assigned to devices, called Ethernet Ring Nodes (ERN)
• Interfaces
• Protocols — ERP alone or with IEEE 802.1ag
• ERP messaging
• ERP operational states
• ERP timers
ERN roles
In an Ethernet ring topology you can assign each ERN one of three roles:
• Ring Protection Link Owner (RPL owner) — One RPL owner must exist in each ring; its role is to
prevent loops by maintaining a break in traffic flow to one configured link while no failure
condition exists within the ring.
• Non-RPL node — Multiple non-RPL nodes, can exist in a ring; but they have no special role and
perform only as ring members. Ring members apply and then forward the information received
in R-APS messages.
• Ring Protection Link (RPL) node — RPL nodes block traffic to the segment that connects to the
blocking port of the RPL owner. The RPL node is used in dual-end blocking and is part of the
FDB optimization feature.
Each device can only have one role at any time. Non-ERN devices can also exist in topologies that
use IEEE 802.1ag.
ERN interfaces
In addition to a role, each ERN has two configured interfaces:
• Left interface
• Right interface
Traffic enters one interface (ingress) and exits the device using the other interface (egress). The
right and left interfaces are physically connected.
You must configure these left and right interfaces in the same pattern across all ERNs within a
topology. For example you can assign the interfaces as left/right, left/right, left/right, and so on. It
is not acceptable, however, to assign interfaces in random order, such as left/right in the
configuration of one ERN and then right/left in the configuration of the next ERN.
Protocols
You can configure standalone ERP or ERP with IEEE 802.1ag support.