A fiber optic switch interconnects fiber optic channels so that a fiber optic network can be implemented. Channel modules provide ports (p1-pi) for connection of the fiber optic channels. Each channel module has a receive memory for temporarily storing incoming data frames from the fiber optic channels associated therewith. A switch module having a data distribution network interconnects each of the channel modules and permits ultimate connection of a source channel to a destination channel. A path allocation system, which controls the switch module, allocates the data paths between the channels. The path allocation system has a scheduler which maintains a destination queue (Q.sub.p1 -Q.sub.pi) for each of the channels, a sentry which determines when a new data frame is ready to be routed, and an arbitrator which arbitrates port availability and which grants transfer requests proposed by the scheduler. Significantly, the arbitrator is equipped with fairness insurance mechanisms for insuring that transfer requests are always timely and efficiently serviced.