US Patent 12126532 Using ARP to identify locally attached source

The present disclosure describes using Address Resolution Protocol (ARP) to determine whether a host is behind a PE or not behind a PE. In a use case, for example, advertising a Selective Provider Multicast Service Interface Auto-Discovery (S-PMSI-AD) route to advertise encapsulation of a multicast group is triggered by receiving multicast traffic for that group from a host device behind the provider edge (PE) device. Multicast traffic received from behind remote PEs will not trigger a S-PMSI-AD route.