Abstract: A flexible scheduler in an ATM switch. The scheduler enables each connection to be served fairly according to associated quality of service parameters, while enabling several other features. A connection can be shaped while minimizing additional memory and processing requirements. Specifically, the conformance time of cells of a connections need not be stored when significant backlog exists in the transmission of the cells. The shaping rate can be dynamically varied. Sequence of cells forming a frame are buffered in the ATM switch until the end of frame cell is received. All the cells of a frame are then sent in quick succession.

Abstract: A switch guaranteeing a minimum amount of memory space for desired connection while allowing efficient dynamic change of maximum memory space that can be used by a connection. Only an amount of memory space which is required for guaranteeing the minimum amount of memory space is reserved. When the reserved space is decremented due to new cells being received on connections, the maximum memory space reserved for each connection is dynamically increased. For multicast connections, only a single copy of the cell data is stored even though a multicast cell is transmitted on several ports. Multicast cells can also be processed using the same signals used for processing unicast cells.