Supported Platforms
Configuring Ethernet Ring Protection Switching (CLI Procedure)
You can configure Ethernet ring protection switching (ERPS) on connected switches to prevent fatal loops from disrupting a network. ERPS is similar to spanning-tree protocols, but ERPS is more efficient than spanning-tree protocols because it is customized for ring topologies. You must configure at least three switches to form a ring. One of the links, called the ring protection link (RPL) end interface, is blocked until another link fails—at this time the RPL link is unblocked, ensuring connectivity.
 | Note: Ethernet OAM connectivity fault management (CFM) can be used with ERPS to detect link faults faster in some cases. See Configuring Ethernet OAM Connectivity Fault Management (CLI Procedure). The time needed for switchover to the ERPS link is affected by three settings—link failure detection time, the number of nodes in the ring, and the time it takes to unblock the RPL after a failure is detected. |
| Note: Do not configure redundant trunk groups on ERPS interfaces. You can configure VSTP on ERPS interfaces if the VSTP uses a VLAN that is not part of the ERPS control VLAN or data channel VLANs. The total number of ERPS and VSTP or MSTP instances is limited to 253. |
Before you begin:
- Optionally, configure two interfaces on each switch as trunk ports. See Configuring Gigabit Ethernet Interfaces (CLI Procedure).
- Configure a VLAN to act as a control VLAN for ERPS if your interfaces are trunk ports. Configure the same VLAN on all switches and associate the two network interfaces from each of the switches with the VLAN. See Configuring VLANs for EX Series Switches (CLI Procedure). If you have multiple ERPS instances, the control VLANs and data channel VLANs must not overlap.
- Data channels are optional on the ERPS link. If you plan to use them, configure a VLAN for each data channel.
To configure ERPS:
| Note: You must configure at least three switches, with only one switch designated as the RPL owner node. |
- RSTP and EPRS cannot both be configured on a ring port,
and RSTP is configured by default. Disable RSTP on each switch interface:user@switch#setrstpinterface interface-name disable
- Create a node ring on each switch:[edit protocols]user@switch# set protection-group ethernet-ring ring-name
- Configure a control VLAN for the node ring if the links
are trunk ports:[edit protocols protection-group ethernet-ring ring name]user@switch# set control-vlan vlan-name-or-vlan-id
- Configure the east interface of the node ring with the
control-channel interface. In addition, configure either the east
interface or the west interface (but not both) as a link end.[edit protocols protection-group ethernet-ring ring-name]user@switch# set east-interface control-channelchannel-nameuser@switch# set east-interface ring-protection-link-end
- Configure the west interface of the node ring with the
control-channel interface. In addition, configure either the east
interface or the west interface (but not both) as a link end.[edit protocols protection-group ethernet-ring ring-name]user@switch# set west-interface control-channel control-channel-interface-addressuser@switch# set west-interface ring protection link end
- Configure only one switch as the RPL owner node:[edit protocols protection-group ethernet-ring ring-name]user@switch# set ring-protection-link-owner
- The restore interval configures the number of minutes
that the node does not process any Ethernet ring protection (ERP)
protocol data units (PDUs). When a link goes down, the ring protection
link (RPL) activates. When the downed link comes back up, the RPL
receives notification, restores the link, and waits the length of
time indicated by the restore interval before issuing another block
on the same link. Optionally, configure the restore interval on each
switch:[edit protocols protection-group ethernet-ring ring-name]user@switch# set restore-interval restore-interval-value
- The guard interval prevents ring nodes from receiving
outdated messages (called RAPs). Optionally, configure the guard interval
on each switch:[edit protocols protection-group ethernet-ring ring name]user@switch# set guard-interval guard-interval-value
Note: Local settings take priority over global settings.
Global settings are used when no local settings are present. Optionally, you can also configure these global settings on the switch:
- restore interval
- guard interval
- ERP traceoptions: file, page size, file size, flag name
- Optionally, reconfigure the global guard interval on each
switch:[edit protocols protection-group ethernet-ring ring name]user@switch# set guard-interval guard-interval-value
- Optionally, reconfigure the global restore interval on
each switch:[edit protocols protection-group ethernet-ring ring name]user@switch# set restore-interval restore-interval-value
- After detection of a link failure, switching takes place
after the hold interval has expired. Optionally, reconfigure the global
hold interval on each switch:[edit protocols protection-group ethernet-ring ring name]user@switch# set hold-interval hold-interval-value
- Optionally, configure VLANs for data channels on the ERPS
link:[edit protocols protection-group ethernet-ring ring name]user@switch# set data-channel vlan-name
