Abstract: A method of queuing data packets, said data packets comprising data packets of a first packet type and data packets of a second packet type. The method comprises grouping received packets of said first and second packet types into an ordered series of groups, each group comprising at least one packet, maintaining a group counter indicating the number of groups at the beginning of the series of groups comprising only packets of the second packet type, and transmitting a packet. A packet of the second packet type is available for transmission if but only if the group counter is indicative that the number of groups at the beginning of the series of groups comprising only packets of the second packet type is greater than zero.

Abstract: A switching device comprising at least one ingress port and at least one egress port. The switching device is arranged to receive data packets through the at least one ingress port and to forward received data packets to respective ones of the at least one egress port. The switching device further comprises a primary buffer arranged to store data packets received via at least one of the least one ingress ports and a secondary buffer associated with the primary buffer. The switching device is adapted to select a data packet from the primary buffer and if but only if the secondary buffer satisfies a least one first predetermined criterion, transfer the selected data packet to the secondary buffer.

Abstract: A switching device comprising a plurality of ingress ports and a plurality of egress ports. The switching device is arranged to receive data packets through the ingress ports and to forward received data packets to respective ones of the egress ports. The switching device further comprises an ingress module for each of the ingress ports, each ingress module being arranged to receive data packets from a respective single one of the ingress ports and to store the received data packets in one of a plurality of data structures provided by the ingress module, each ingress module being further configured to select a data packet from one of the plurality of data structures, and to request permission to transmit the selected data packet to an egress port.