A communication apparatus includes at least one input port, multiple output ports, at least one Serial-to-Parallel (S/P) converter and at least one Parallel-to-Serial (P/S) converter. The S/P converter is operative to receive from the input port an input data stream that is to be cross-connected to a destination output port, and to separate the input data stream into multiple sub-streams. Each of the switching planes includes at least one input for receiving a respective sub-stream from the S/P converter; multiple outputs, each output associated with a respective one of the output ports; and switching circuitry, which is configured to switch the respective sub-stream to the output that is associated with the destination output port. The P/S converter is coupled to the outputs of the switching planes so as to combine the multiple sub-streams switched by the switching circuitry into a combined output data stream at the destination output port.