Core isolation for logical tunnels stitching multi-homed EVPN and L2 circuit

Techniques are described to provide layer 2 (L2) circuit failover in the event connectivity to an Ethernet Virtual Private Network (EVPN) instance is lost. For example, if one of multi-homed provider edge (PE) devices loses connectivity to the EVPN instance, the PE device may mark its customer-facing interface as down and propagate the interface status to the access node such that the access node may update its routing information to switch L2 circuits to another one of the multi-homed PE devices having reachability to the EVPN instance. In some examples, the plurality of PE devices may further implement Connectivity Fault Management (CFM) techniques to propagate the interface status to the access node such that the access node may update its forwarding information to send traffic on a different L2 circuit to another one of the multi-homed PE devices having reachability to the EVPN instance.