A network switch adaptive routing mechanism wherein each input port includes an input arbiter and each output port includes and output arbiter

A network switch device comprising a plurality of input ports and output ports, a switch network comprising interconnected switch elements arranged to connect any input to any output, each output port including an output arbiter operable to determine which switch element is to connect an input port to that output port, at least one input port including an input arbiter operable to determine which switch element or elements are to complete a connection from the input port concerned to an output port, wherein each output arbiter is operable to receive a switch request signal from a switch element connected with an associated output port, to determine to which input port the output port is connected, in dependence upon such a received switch request signal, and to signal connection status information via said switch elements to that input arbiter associated with said input port, the input arbiter being operable to select only one output port in dependence upon received connection status information, thereby to complete a single connection from said input port to a single output port. The crossbar switch arrangement provides a connection mechanism that allows concurrent adaptive routing selections of arbitrary connections to switch outputs from all of the switch inputs from a single data transfer cycle.