An apparatus includes a collective switch hardware architecture, including an input arrangement circuit including multiple input ports and multiple outputs. The input arrangement circuit routes its multiple input ports to selected ones of its outputs. The collective switch hardware architecture includes collective reduction logic coupled to the multiple outputs of the input arrangement circuit and having multiple outputs. The collective reduction logic includes ALU(s) and arbitration and control circuitry. The ALU(s) and arbitration and control circuitry support multiple simultaneous collective operations from different collective classes, and support arbitrary input port and output port mapping to different collective classes. The collective switch hardware architecture further includes an output arrangement circuit including a multiple inputs coupled to the multiple outputs of the collective reduction logic and including multiple output ports. The output arrangement circuit is configured to route its multiple inputs to selected ones of its output ports.