Call scheduling in multicasting packet switching

The implementation and performance of multicast packet switching in a broadband network environment are discussed. In terms of scheduling the transmission of the copies of the packet onto output ports, two basic service disciplines have been defined: (1) one-shot scheduling where all the copies are transmitted in the same time slot; and (2) call splitting with transmission over several time slots. As subcategories of call splitting strict-sense call splitting specifies that each packet can send at most one copy to the destination per time slot and wide-sense call splitting does not carry this restriction. A novel scheme called revision scheduling is proposed to mitigate the head of line blocking effect by sequentially combining the one-shot scheduling and the call splitting disciplines. Schematic structures are introduced for each category of scheduling, in the form of combinational logic circuits which are designed to resolve the output contentions corresponding to call scheduling disciplines, by incorporating a cyclic priority access policy. To compare the performances of various techniques, simulation studies were performed