Patent ID: 6704321
Filing Date: 2004-03-09
Classification: H04L

Abstract:
A traffic shaper for absorbing a cell delay variation of cell flow in each of virtual connections in an ATM (asynchronous transmission mode) network, said traffic shaper comprising:a cell identification part for identifying a virtual connection allocated to an input cell; a cell memory for storing input cells into respective virtual queues, each corresponding to the virtual connection, in accordance with the identified virtual connection of each input cell; a sending-out time determination part for determining a sending-out time for each cell stored in the cell memory on the virtual connection basis; and a cell memory control part for performing a cell output from each virtual queue in accordance with the sending-out time determined for each cell, and performing an output competition control by selecting a cell to be output among cells having the same sending-out time in different virtual queues in accordance with a predetermined output priority assigned to each virtual connection, wherein said cell memory control part comprises: a priority table for indicating an output priority for each virtual connection currently being established; a virtual queue state table for indicating each virtual queue state including information of an existence of a cell in the queue, sending-out scheduled time determined for the queue and a presence of a cell sending-out request for the queue; and a cell sending-out control part for setting a cell sending-out request for each virtual queue in the virtual queue state table when corresponding information indicating cell existence in the queue and the sending-out scheduled time is now or past, selecting a virtual queue, among virtual queues for which a cell sending-out request being set in the virtual queue state table, corresponding to the virtual connection having the highest predetermined output priority, and sending out a cell from the selected virtual queue.