A network interface device includes a fabric interface, adapted to exchange messages over a switch fabric with a plurality of host processors, the messages containing data, and a network interface, including one or more ports adapted to be coupled to a network external to the switch fabric. Message processing circuitry is coupled between the fabric interface and the network interface, so as to enable at least first and second host processors among the plurality of the host processors to use a single one of the ports substantially simultaneously so as to transmit and receive frames containing the data over the network.