LACP in EVPN active-active multihoming

An extra level of redundancy can be achieved in an Ethernet VPN (EVPN) active-active multihoming network by configuring the Link Aggregation Control Protocol (LACP) on both the endpoints of the link between the multihomed customer edge (CE) and provider edge (PE) devices. The link aggregation group (LAG) interface of the multihomed CE-PE link can either be in the active or in the standby state. The interface state is monitored and operated by LACP to ensure fast convergence on isolation of a multihomed PE device from the core.

When there is a core failure, a traffic null route can occur at the isolated PE device. With the support for LACP on the CE-PE link, at the time of core isolation, the CE-facing interface of the multihomed PE device is set to the standby state, thereby blocking data traffic transmission from and toward the multihomed CE device. After the core recovers from the failure, the interface state is switched back from standby to active.

To configure LACP in EVPN active-active multihoming network:

• On the multihomed CE device include the lacp active statement at the [edit interfaces aex aggregated-ether-options] hierarchy.
• On the multihomed PE device include the lacp active statement at the [edit interfaces aex aggregated-ether-options] hierarchy, and include the service-id number statement at the [edit switch-options] hierarchy.