LAG standby signaling to the CE on non-DF EVPN PEs (single-active)

As described in EVPN for MPLS tunnels, EVPN single-active multihoming PEs that are elected as non-DF must notify their attached CEs so the CE does not send traffic to the non-DF PE. This can be performed on a per-service basis that is based on the ETH-CFM and fault-propagation. However, sometimes ETH-CFM is not supported in multihomed CEs and other notification mechanisms are needed, such as LACP standby or power-off. This scenario is illustrated in Figure 1.

Figure 1. LACP standby signaling from the non-DF

Based on Figure 1, the multihomed PEs is configured with multiple EVPN services that use ES-1. ES-1 and its associated LAG is configured as follows:

*[ex:configure lag 1]
A:admin@PE-2# info
    admin-state enable 
    standby-signaling {power-off|lacp} 
    monitor-oper-group ”DF-signal-1" 
    mode access 
    port 1/1/c2/1 { 
    }
<snip>
ex:configure service system bgp evpn]
A:admin@PE-2# info 
    ethernet-segment "ES-1" { 
        admin-state enable 
        esi 0x01010000000000000000 
        multi-homing-mode single-active 
        oper-group ‟DF-signal-1” 
        association { 
            lag 1 { 
            } 
<snip>

When the oper-group is configured on the ES and monitored on the associated LAG:

Oper-groups cannot be assigned to ESs that are configured as virtual, all-active or service-carving mode auto.