A method being performed by a switch connectable to a first network via a network interface and to a Customer Premises equipment, CPE, addressable by a first Medium Access Control, MAC, address via an interface of a first type , the method comprising: receiving , via the interface of the first type, a first unicast frame from the CPE, the first unicast frame having a destination address that is a second MAC address associated with the first network; and receiving , via the network interface, a second frame from the first network, the second frame having a destination address that is the first MAC address; characterized in that: the first network is an Open System Interface, OSI, Layer-2 Ethernet bridged network that uses MAC address-based routing, and the method further comprising: marking the first unicast frame as a first interface frame by placing an indication in the first unicast frame that the frame is a frame received via an interface of the first type: forwarding the first unicast frame to the first network as a marked frame; responsive to the second frame being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, discarding the second frame; and responsive to the second frame being a non-unicast frame or not being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, forwarding the frame to the CPE via the first type interface. receiving , via the interface of the first type, a first unicast frame from the CPE, the first unicast frame having a destination address that is a second MAC address associated with the first network; and receiving , via the network interface, a second frame from the first network, the second frame having a destination address that is the first MAC address; characterized in that: the first network is an Open System Interface, OSI, Layer-2 Ethernet bridged network that uses MAC address-based routing, and the method further comprising: marking the first unicast frame as a first interface frame by placing an indication in the first unicast frame that the frame is a frame received via an interface of the first type: forwarding the first unicast frame to the first network as a marked frame; responsive to the second frame being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, discarding the second frame; and responsive to the second frame being a non-unicast frame or not being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, forwarding the frame to the CPE via the first type interface. forwarding the first unicast frame to the first network as a marked frame; responsive to the second frame being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, discarding the second frame; and responsive to the second frame being a non-unicast frame or not being a unicast frame that comprises the indication that the frame is a frame received via an interface of the first type, forwarding the frame to the CPE via the first type interface. <EOS>