Abstract: A system is disclosed for routing data cells from at least one of a plurality of source port processors to at least one destination port processor. Such a system contemplates each cell comprising a plurality of cell frame portions. In a preferred embodiment of the system of the present invention, each cell generated by the at least one source port processor is separated into its constituent frame portions. Each frame portion has associated therewith a first characteristic and a second characteristic. The cell portions are transmitted to at least one port associated with at least one crossbar chip. The at least one port is in communication with at least two of the plurality of source port processors. Each cell portion is selectively transmitted according to its first characteristic to a corresponding one of the crossbar chips. Each cell portion is selectively transmitted according to its second characteristic to a corresponding one of the ports of the corresponding one of the crossbar chips.

Abstract: A method of facilitating the scheduling of a first multicast request signal of a series of multicast request signals is disclosed, wherein the first request signal is generated to enable the transmission of a multicast data cell by a source port processor to at least one destination port processor. In a preferred embodiment of the invention, the first request signal is received by a roster storage chip associated with a scheduler subsystem. The first request signal has associated therewith a multicast label of a first value and is adapted to schedule transmission of the first multicast cell to the at least one destination port processor at a first time. A roster of the at least one destination port processor to which the first multicast cell is destined is then generated. A dependence distance associated with the first request signal is determined. The dependence distance comprises the numerical value of the difference between a current multicast cell number (CMCN) and a previous multicast cell number (PMCN).

Abstract: A Communications system having a protocol whereby a plurality of stations (100) are granted access to a network. Each station may send a packet of data in each cycle of operation. At least one station with data to transmit identifies the station that immediately precedes it among stations which are to transmit data (e.g., as indicated in a corresponding reservation slot). On the basis of that identification the one station transmits its data packet promptly after the preceding station has begun transmitting its data packet. At least in same cases the one station initiates its transmission prior to having finished receiving the packet transmitted by the preceding station at a time calculated to avoid data collision.