Patent ID: 6400718
Filing Date: 2002-06-04
Classification: H04L

Abstract:
A cell switching device comprising:first cell switching circuitry including a first input port for receiving cells for ATM (Asynchronous Transfer mode) communication, and a first cell switch including a queue circuit for temporarily storing said cells, said first cell switch outputting said cells from said queue circuit to a first output port matching with a transfer route; second cell switching circuitry including a second input port for receiving cells for ATM communication, and a second cell switch including a queue circuit for temporarily storing said cells, said second cell switch outputting said cells from said queue circuit to a second output port matching with a transfer route; wherein when either one of said first and second cell switching circuitry is held in an active state, the other of said first and second cell switching circuitry is held in a standby state; said first cell switching circuitry further including a first cell gate for selectively passing the cells received to said first input port or blocking said cells, a first shaper including a queue circuit for temporarily storing the cells output from said first output port to thereby adjust intervals between said cells to be transferred, and a second cell gate for selectively passing the cells output from said first shaper or blocking said cells; said second cell switching circuitry further including a third cell gate for selectively passing the cells received to said second input port or blocking said cells, a second shaper including a queue circuit for temporarily storing the cells output from said second output port to thereby adjust intervals between said cells to be transferred, and a fourth cell gate for selectively passing the cells output from said second shaper or blocking said cells; said first cell gate and said third cell gate having a common input connected to receive cells; a cell outputting circuit for selecting and outputting the cells output from either one of said second cell gate and said fourth cell gate held in an active state; and a controller for controlling the passage of the cells through said first to said fourth cell gate and controlling said first cell switch, said second cell switch, said first shaper and said second shaper to thereby effect hit-less switching from said one cell switching circuitry held in the active state to said other cell switching circuitry held in the standby state.