A switching system having input ports and output ports and comprising an input queued (IQ) switch with virtual channels. Typically, only one virtual channel can, at a given time, access a given output port. Typically, the IQ switch includes an arbiter apparatus that controls the input ports and output ports to ensure that an input port transmits at most one cell at a time, and/or that an output port receives a cell over only one virtual channel, and/or an output port receives at most one cell at a time.