Abstract: In a routing switch a technique for routing messages from an input port to an output port involves storing a plurality of sets of routing information in the routing switch, each set associated with a value of a header of the message. The technique involves grouping outputs which are suitable for outputting the same message. In the routing network, unicast packets include multiple headers and multicast packets include single headers. Sequence numbers of packets in the message are encoded in the packets by use of a longitudinal checksum. In the routing switch, messages are prioritized for routing in dependence on a priority allocated to the respective header.

Abstract: A communication system includes two high speed communication links formed by pairs of transformers at either end thereof. A phantom circuit formed by the pairs of transformers is used to distribute power to devices connected to the high speed links. In transmission part of a communications system, data is transmitted under the control of a continuously variable frequency clock. Transmission is on parallel data-strobe links, and the receive includes circuitry to identify on which parallel the data signal is preset. A method and circuitry is provided for transmitting and receiving dc balanced data strobe signals.