(MultiProtocol Over ATM) An ATM Forum standard that provides routing of legacy protocols (IP, IPX, etc.) over ATM networks. MPOA separates the routing processing from the actual forwarding. A route server performs the routing calculations and sends its results to the ATM switches and edge devices which perform high-speed forwarding of the packets. Before MPOA, LAN emulation (LANE) required a router to communicate between subnets. See virtual routing, I-PNNI and LANE.