Patent ID: 6449283
Filing Date: 2002-09-10
Classification: H04L

Abstract:
In a switch having input ports, output ports, and a switching fabric for selectively connecting an input port to an output port, the switching fabric including a matrix of crosspoints having rows associated with the input ports and columns associated with the output ports, a method for arbitrating among cells contending for a particular one of the output ports, the method comprising steps of:a) for each column of crosspoints, passing a token in a ring defined by the crosspoints; b) for each column of crosspoints, defining groups of crosspoints; c) for each column of crosspoints and for each of the groups of crosspoints, logically ORing requests for the output port associated with the column to generate a group request; d) for each column of crosspoints and for each of the groups of crosspoints, if the group request is LOW, and the token is received, passing received token to a next group of crosspoints in the ring; and e) for each column of crosspoints and for each of the groups of crosspoints, if the group request is HIGH and the token is received, passing the received token to successive crosspoints of the group of crosspoints, wherein, when a crosspoint having a request receives the token, the cell associated with that crosspoint wins the arbitration.