A device comprising: a control bus; a plurality of requesting circuits each accessible on the control bus, wherein each of the plurality of requesting circuits is operable to dispatch read or write requests to the control bus for delivery to at least one of a plurality of receiving circuits, and the plurality of receiving circuits each accessible on the control bus, and each of which is operable to receive requests from the at least one control bus and service the requests by providing at least one of read or write access to storage associated with the respective receiving circuit, wherein the control bus provides a ring path configured to support, the requests in circulation in the ring path, wherein the control bus is configured to propagate each of at least some of the requests at least until those requests have been serviced by at least one of the receiving circuits.