Patent ID: 6144640
Filing Date: 2000-11-07
Classification: H04L,H04Q

Abstract:
A routing switch for connection to a source of digital signals for bi-directional transmission of digital signals from said source, said digital signals including at least some digital signal cells of at least two types, a first type requiring integrity of cell transmission while accepting a variable bit rate of transmission, and a second type accepting some loss of cells in transmission, said switch comprising:a plurality of input ports for receiving input cells,a plurality of output ports for outputting output cells,buffer circuitry selectively connectable to both said input and output ports for holding a plurality of cells of each type after receipt by at least one of said input ports and prior to output by at least one of said output ports, said buffer circuitry comprising:a first reserved buffer capacity for cells of said first type,a second reserved buffer capacity for cells of said second type, andcontrol circuitry for determining whether each input cell is of said first or second type, loading each input cell of said first type into said buffer circuitry and set a flow control signal to a selected state for output from the switch to said source to prevent input to the switch of cells of said first type if a predetermined threshold for said first reserved buffer capacity is reached, and loading each input cell of said second type into said buffer circuitry if the number of cells of said second type in said buffer circuitry has not reached a predetermined threshold for said second reserved buffer capacity, or to discard input cells of said second type if said predetermined threshold for said second reserved buffer capacity has been reached.