Patent ID: 7050440

Claim:
A method for providing routing capability for variable-length unit traffic in a fixed-length cell routing switch with a shared memory and a plurality of registers each associated with a particular input and a particular output of said switch comprising the steps of: segmenting an incoming variable-length unit, a frame, into a plurality of fixed-length cells including a start-of-frame cell, one or more continuation cell(s), and an end-of-frame cell, routing said fixed-length cells through said switch, by defining a predetermined first condition for said shared memory, defining a predetermined second condition for said frame and its cells, controlling a cell's entry into said shared memory depending upon said first condition, and controlling transmission of a said cell of said frame depending upon said second condition; and storing an indication that said particular output is “active” with respect to said particular input, said indication being set when a start-of-frame cell of one of the copies a specific frame received on said particular input is transmitted on said particular output and said one of the copies is the last copy of the specific frame to be transmitted, and said indication being reset when the corresponding end-of-frame cell is transmitted at said particular output.