Abstract: Multicast packets that are received on a port of a network device and forwarded to multiple output ports are stored in memory and respective primary control entries which define them are converted to secondary control entries defining multiple unicast packets before a scheduling algorithm is applied. The packets are reconstituted after the application of the scheduling algorithm has been applied to the control entries. For VPLS packets that are received on a single port and replicated multiple times on one or more output ports, a replication database may be used in conjunction with a replication engine to convert the control entry for a received packet into multiple control entries defining unicast packets for each of the destination ports before the scheduling algorithm is applied. This method is applicable to the replication of packets onto a Virtual Private LAN.

Abstract: A power supply unit controller for a rack enclosure in which a plurality of devices communicate via a backplane is disclosed. The controller reads at least one signal indicative of an output supply level being provided to the backplane by a power supply unit associated with the power supply unit controller and stores at least one value associated with a respective one of the at least one signal. The controller communicates the at least one value to one of the devices; and receives power for the power supply unit controller from the backplane.

Abstract: A bus analyser for analysing the operation of a bus to which a plurality of devices are connectable is disclosed. The devices are operatively coupled to a host device running a host application and the analyser is adapted to be housed in an enclosure which, in use, houses at least one of the devices. The analyser is arranged to extract data from the bus, process the extracted data; and communicate processed data to an environmental control and monitoring unit through a secondary communication bus.

Abstract: A power supply unit controller for a rack enclosure in which a plurality of devices communicate via a backplane is disclosed. The controller reads at least one signal indicative of an output supply level being provided to the backplane by a power supply unit associated with the power supply unit controller and stores at least one value associated with a respective one of the at least one signal. The controller communicatwa the at least one value to one of the devices; and receives power for the power supply unit controller from the backplane.

Abstract: A bus analyser for analysing the operation of a bus to which a plurality of devices are connectable is disclosed. The devices are operatively coupled to a host device running a host application and the analyser is adapted to be housed in an enclosure which, in use, houses at least one of the devices. The analyser is arranged to extract data from the bus, process the extracted data; and communicate processed data to an environmental control and monitoring unit through a secondary communication bus.