Configuring ERP with IEEE 802.1ag

To configure and initialize ERP using APS and IEEE 802.1ag (Dot1ag), you must set up one RPL owner and one or more non-RPL nodes. Other nonparticipating switches can exist in the ring.

You must perform the following minimum configuration tasks for the RPL owner:

Configure an ERP instance.
Set the left and right interfaces.
Set the role as owner.
Set the RPL.
Enable the configuration.

You must perform the following minimum configuration tasks for each non-RPL node:

Configure an ERP instance.
Set the left and right interfaces.
Configure the maintenance entity group end points (MEPs) from each ERN, which can have a role of RPL owner or non-RPL node, adjacent to switches not participating in the ERP configuration.
Enable the configuration.

IEEE 802.1ag can be used to monitor the ERP interfaces for signal failures. The dot1ag-compliance command allows MDs and MAs configured as part of IEEE 802.1ag to be associated with an ERP instance. Note the following:

With Dot1ag compliance enabled, ERP relies on signal fail or signal OK messages from the Dot1ag module.
Before enabling Dot1ag compliance in ERP, the user must create a CFM session between the links of the ERP instance.
For each ring interface, an MEP must be configured and the direction of the MEP must be down.
Once the CFM session is configured, the user must associate an MEP with the corresponding ERP ring interface.
With a CCM interval of 3.3 ms, CFM can detect a link failure within 10 ms. This helps ERP to achieve faster protection switching times, with traffic converging within 50 ms.

The following example configures IEEE 802.1ag compliance.

device(config)# erp 1
device(config-erp-1)# dot1ag-compliance
device(config-dot1ag-compliance)# left-interface domain-name md1 ma-name ma1 mep 2 remote-mep 4
device(config-dot1ag-compliance)# right-interface domain-name md1 ma-name ma3 mep 2 remote-mep 4
device(config-dot1ag-compliance)# enable

Use the no dot1ag-compliance command to disable the feature.

The domain-name parameter specifies the MD name for 802.1ag CFM.

The ma-name parameter specifies the maintenance association name. This can be up to 21 characters long.

Refering to the example topology above, corresponding configurations for this feature on Node 1 and Node 2 are as follows.

Node 1 Dot1ag configuration

protocol cfm
domain-name md1 id 1 level 7
ma-name ma2 id 2 vlan 222 priority 7
ccm-interval 3.3-ms
mep 2 down ethernet 0/1
!
!
ma-name ma3 id 3 vlan 222 priority 7
ccm-interval 3.3-ms
mep 1 down ethernet 0/2
!
erp 222
left-interface vlan 222 ethernet 0/1
right-interface vlan 222 ethernet 0/2
dot1ag-compliance 
left-interface domain-name md1 ma-name ma2 mep 2 remote-mep 1
right-interface domain-name md1 ma-name ma3 mep 1 remote-mep 2
enable
end

Node 2 Dot1ag configuration

protocol cfm
domain-name md1 id 1 level 7
  ma-name ma2 id 2 vlan 222 priority 7
   ccm-interval 3.3-ms
   mep 1 down ethernet 0/1
   !
  !
  ma-name ma1 id 1 vlan 222 priority 7
   ccm-interval 3.3-ms
   mep 2 down ethernet 0/2
!
erp 222
left-interface vlan 222 ethernet 0/1
right-interface vlan 222 ethernet 0/2
dot1ag-compliance
  left-interface domain-name md1 ma-name ma2 mep 1 remote-mep 2
  right-interface domain-name md1 ma-name ma1 mep 2 remote-mep 1
!
rpl-owner
rpl vlan 222 ethernet 0/2
enable
end