Path allocation system and method with fairness insurance mechanism for a fiber optic switch

摘要

A fiber optic switch (30) interconnects fiber optic channels (32) so that a fiber optic network can be implemented. Channel modules (34) provide ports (p1-pi) (33) for connection of the fiber optic channels (32). Each channel module (34) has a receive memory (84) for temporarily storing incoming data frames from the fiber optic channels (32) associated therewith. A switch module (36) having a data distribution network (42) interconnects each of the channel modules (34) and permits ultimate connection of a source channel (32) to a destination channel (32). A path allocation system (50), which controls the switch module (36), allocates the data paths between the channels (32). The path allocation system (30) has a scheduler (104) which maintains a destination queue (Qp1-Qpi) for each of the channels (32), a sentry (104) which determines when a new data frame (11) is ready to be routed, and an arbitrator (123) which arbitrates port availability and which grants transfer requests proposed by the scheduler (104). Significantly, the arbitrator (123) is equipped with fairness insurance mechanisms (130', 130'') for insuring that transfer requests are always timely and efficiently serviced.