mLACP and L3VPN Static Routes Overview
In a network where L3VPN and Cisco multichassis Link Aggregation Control Protocol (mLACP) features are enabled, and logical port channels have subinterfaces that are not configured with Link Aggregation Group (LAG) or Multichassis-LAG (MC-LAG), the subinterfaces associated with both active and standby PoAs can be in the active (UP) state.
Currently, the static routes are advertised through both active and standby PoAs to the core MPLS, because all port channel subinterfaces are active on both PoAs.
To prevent the static routes being advertised on a standby PoA, when a PoA moves to an inactive state, the static routes are blocked on all Layer 3 port-channel subinterfaces. When a PoA moves to an active state, static routes are allowed on all Layer 3 port-channel subinterfaces.
To block the standby PoA from advertising static routes to MPLS, MC-LAG notifies the platform manager about the change in the PoA state. The platform manager shuts down all subinterfaces associated with the standby PoA.
To allow the static routes on subinterfaces, when a PoA moves to active state, the platform manager activates all subinterfaces associated with the active PoA.