Abstract: A switch includes at least one input configured to receive data and at least two outputs configured to send data to at least two further switches in a network via at least two output links. Each output link has a known hop value. The switch further includes a direction determinator that determines a routing direction for the data from information identifying a relative location of the switch in the network and information identifying a destination of said data. A distributor within the switch processes the routing direction and direction information about each output link in order to select one of said at least two outputs for outputting said data. The selection that is made prioritizes output links for selection which have relatively higher known hop values.

Abstract: A switch for connection in a network of other like switches and includes memory for storing data packets, a control system arranged to control the switch to, upon receipt at one of the ingress or egress ports of notification of congestion at a downstream congested port, either store at said ingress port or egress port data packets received for said congested port or to communicate with an upstream port for storage at said upstream port of data packets destined for the congested port, and in dependence on the current of stored data, to send a message to a further upstream port informing the further upstream port of the congestion downstream. The memory is provided substantially only at the ingress ports or the egress ports of the switch.

Abstract: A switch includes at least one input configured to receive data and at least two outputs configured to send data to at least two further switches in a network via at least two output links. Each output link has a known hop value. The switch further includes a direction determinator that determines a routing direction for the data from information identifying a relative location of the switch in the network and information identifying a destination of said data. A distributor within the switch processes the routing direction and direction information about each output link in order to select one of said at least two outputs for outputting said data. The selection that is made prioritizes output links for selection which have relatively higher known hop values.

Abstract: A method of congestion management within a switch or network of connected switches is provided, wherein the or each of the switches has a plurality of ingress ports and a plurality of egress ports. The method involves, when congestion is detected at a first ingress or egress port, sending a message to an upstream port connected to the first ingress or egress port indicating that congestion has occurred at a particular port and requesting storage at the upstream port of data packets destined for that port; and, in dependence on the amount of data packets destined for the congested port stored at the upstream port, sending from the upstream port to a further upstream port a message informing the further upstream port of the congestion at the congested port, the further upstream port storing at the further upstream port data packets destined for the congested port.

Abstract: A switch for connection in a network of other like switches and includes memory for storing data packets, a control system arranged to control the switch to, upon receipt at one of the ingress or egress ports of notification of congestion at a downstream congested port, either store at said ingress port or egress port data packets received for said congested port or to communicate with an upstream port for storage at said upstream port of data packets destined for the congested port, and in dependence on the current of stored data, to send a message to a further upstream port informing the further upstream port of the congestion downstream. The memory is provided substantially only at the ingress ports or the egress ports of the switch.

Abstract: A method of congestion management within a switch or network of connected switches is provided, wherein the or each of the switches has a plurality of ingress ports and a plurality of egress ports. The method involves, when congestion is detected at a first ingress or egress port, sending a message to an upstream port connected to the first ingress or egress port indicating that congestion has occurred at a particular port and requesting storage at the upstream port of data packets destined for that port; and, in dependence on the amount of data packets destined for the congested port stored at the upstream port, sending from the upstream port to a further upstream port a message informing the further upstream port of the congestion at the congested port, the further upstream port storing at the further upstream port data packets destined for the congested port.