Abstract: The present invention discloses a memory sharing mechanism based on priority elevation. In accordance with the present invention, there is provided an apparatus and method for transporting packets of data in a communication device, wherein each packet is assigned one of several priorities and received based on memory state information. The method comprises the steps of storing the received packets in a memory and modifying the assigned priority of any of the packets causing congestion within the memory.

Abstract: A method and system for reducing arbitration latency employs speculative transmission (STX) without prior arbitration in combination with routing fabric scheduled arbitration. Packets are sent from source locations to a routing fabric through scheduled arbitration, and also through speculative arbitration, to non-contentiously allocate outputs that were not previously reserved in the routing fabric to the speculatively transmitted packets.

Abstract: A method for scheduling unicast and multicast traffic in an interconnecting fabric performs within each time slot the following steps. First a multicast cell scheduling (61) and independently thereof a unicast cell scheduling (62) is performed. Then, the unicast cell schedule and the multicast cell schedule are merged to a merged schedule (63), wherein in the case a scheduled connection cannot be included in the merged schedule the scheduled connection is included in the merged schedule in a later time slot (66, 63).

Abstract: A communication system which consists of several modules—operating in parallel on segments of a packet—to increase speed and handling capacity. One module acts as master, the others are slave modules controlled by control signals derived by the master module. It is important that in each module the data segment and the respective control signal of each packet are correctly synchronized, because in large systems the data paths carrying packet segments and the control signal paths may have substantially different delays. The invention provides for measurement of the propagation delay differences and for introducing a controlled delay in each slave module, so that data segments and control signals can be correctly correlated by delaying either the one or the other. Synchronization packets are transmitted besides normal data packets, for obtaining time stamps which are used to determine the delay difference.

Abstract: A method is described to operate a crossbar switch comprising a crossbar fabric with N sending and M receiving ports, with port cards connected to at least one sending and/or receiving port each of the crossbar fabric, said crossbar switch further comprising a control unit connected with the port cards via discrete control channel links, wherein C ports are clustered on a single receiving port card so that such a receiving port card in a single time-step can receive up to C data cells from C sending port cards simultaneously. According to said method the control channel links are used to relay up to C acknowledgements between at least one receiving port card and at least one sending port card.

Abstract: A communication system which consists of several modules—operating in parallel on segments of a packet—to increase speed and handling capacity. One module acts as master, the others are slave modules controlled by control signals derived by the master module. It is important that in each module the data segment and the respective control signal of each packet are correctly synchronized, because in large systems the data paths carrying packet segments and the control signal paths may have substantially different delays. The invention provides for measurement of the propagation delay differences and for introducing a controlled delay in each slave module, so that data segments and control signals can be correctly correlated by delaying either the one or the other. Synchronization packets are transmitted besides normal data packets, for obtaining time stamps which are used to determine the delay difference.

Abstract: For switching or transmitting data packets, one can provide communication systems which consist of several modules —operating in parallel on segments of a packet —to increase speed and handling capacity. One module acts as master, others are slave modules controlled by control signals derived by the master module. It is important to correctly synchronize in each module the data segment and the respective control signal of each packet, because in large systems the data paths carrying packet segments and the control signal paths may have substantially different delays. The invention provides for measurement of the propagation delay differences and for introducing a controlled delay in each slave module, so that data segments and control signals can be correctly correlated by delaying either the one or the other. Synchronization packets are transmitted besides normal data packets, for obtaining time stamps which are used to determine the delay difference.

Abstract: A method is described to operate a crossbar switch comprising a crossbar fabric with N sending and M receiving ports, with port cards connected to at least one sending and/or receiving port each of the crossbar fabric, said crossbar switch further comprising a control unit connected with the port cards via discrete control channel links, wherein C ports are clustered on a single receiving port card so that such a receiving port card in a single time-step can receive up to C data cells from C sending port cards simultaneously. According to said method the control channel links are used to relay up to C acknowledgements between at least one receiving port card and at least one sending port card.

Abstract: A method for scheduling unicast and multicast traffic in an interconnecting fabric performs within each time slot the following steps. First a multicast cell scheduling (61) and independently thereof a unicast cell scheduling (62) is performed. Then, the unicast cell schedule and the multicast cell schedule are merged to a merged schedule (63), wherein in the case a scheduled connection cannot be included in the merged schedule the scheduled connection is included in the merged schedule in a later time slot (66, 63).

Abstract: The present invention discloses a memory sharing mechanism based on priority elevation. In accordance with the present invention, there is provided an apparatus and method for transporting packets of data in a communication device, wherein each packet is assigned one of several priorities and received based on memory state information. The method comprises the steps of storing the received packets in a memory and modifying the assigned priority of any of the packets causing congestion within the memory.

Abstract: The present invention discloses a memory sharing mechanism based on priority elevation. In accordance with the present invention, there is provided an apparatus and method for transporting packets of data in a communication device, wherein each packet is assigned one of several priorities and received based on memory state information. The method comprises the steps of storing the received packets in a memory and modifying the assigned priority of any of the packets causing congestion within the memory.

Abstract: The present invention discloses a scalable flow-control mechanism. In accordance with the present invention, there is provided a switching device for transporting packets of data, the packets being received at the switching device based on flow-control information, the device comprising a memory for storing the packets, a credit counter coupled to the memory for counting a credit number of packets departing from the memory, and a scheduler unit coupled to the credit counter for deriving the flow-control information in response to the credit number. Moreover, a switching apparatus and a method for generating flow-control information is disclosed.

Abstract: A real-time load-balancing system for distributing a sequence of incoming data packets emanating from a high speed communication line to a plurality of processing means, each operating at a capacity that is lower than the capacity of the high speed communication line; the system according to the invention comprises: a parser capable of extracting a configurable set of classifier bits from the incoming packets for feeding into a compression means; the compression means is capable of reducing a bit pattern of length K to a bit pattern having a length L which is a fraction of K; a pipeline block for delaying incoming packets until a load balancing decision is found, and an inverse demultiplexer for receiving a port identifier output from said compression means as selector and for directing pipelined packets to the appropriate output port.

Abstract: The present invention discloses a memory sharing mechanism based on priority elevation. In accordance with the present invention, there is provided an apparatus and method for transporting packets of data in a communication device, wherein each packet is assigned one of several priorities and received based on memory state information. The method comprises the steps of storing the received packets in a memory and modifying the assigned priority of any of the packets causing congestion within the memory.

Abstract: The present invention discloses a scalable flow-control mechanism. In accordance with the present invention, there is provided a switching device for transporting packets of data, the packets being received at the switching device based on flow-control information, the device comprising a memory for storing the packets, a credit counter coupled to the memory for counting a credit number of packets departing from the memory, and a scheduler unit coupled to the credit counter for deriving the flow-control information in response to the credit number. Moreover, a switching apparatus and a method for generating flow-control information is disclosed.