Cisco Nokia Arista Cisco Cisco The Interconnect Solution for Ethernet VPN defines Unknown MAC (Media Access Control) Route (UMR) utilization for Data Center Interconnect (DCI) when EVPN MPLS or EVPN VXLAN is used as an overlay network for such interconnects. The use of UMR has implications for EVPN MAC mobility procedures, for EVPN L2 and IRB operations, and for EVPN Proxy ARP/ND operations. This document describes additional enhancements required to EVPN procedures and operations when using UMR. This document updates RFC9014 to clarify and extend the proceduresfor UMR usage.