The invention features a method, apparatus, and computer program. The apparatus comprises a plurality of ports each adapted to receive Ethernet packets; and a data-link layer switch controller, when one of the Ethernet packets comprises an Internet protocol (IP) multicast packet comprising an IP multicast destination address and an IP source address, to select one or more of the ports based upon the IP multicast destination address and the IP source address; wherein the selected one or more ports transmit the Ethernet packet.