Patent ID: 7164682
Filing Date: 2007-01-16
Classification: H04L,H04Q

Abstract:
1. An Asynchronous Transfer Mode (ATM) communication apparatus in a point-to-multipoint optical transfer system where the ATM communication apparatus is connected to a plurality of optical network units through an optical branching device, and the ATM communication apparatus, receives a multiplexed signal obtained when the optical branching device multiplexes optical signals transmitted by the optical network units, and branches an optical signal at the optical branching device to transmit to the optical network units, the ATM communication apparatus sends to each of the optical network units by using a certain area in an ATM cell, transmission timing and a transmission bandwidth of an ATM cell to be transmitted to the ATM communication apparatus to give an access right to control a communication bandwidth to perform ATM-cell receiving control in the optical transfer system, the ATM communication apparatus comprising: a traffic supervisory unit for supervising a traffic situation of ATM cells sent to said ATM communication apparatus from the optical network units, the traffic supervisory unit having a supervisory unit of a receiving bandwidth for detecting the receiving bandwidth for receiving ATM cells from each of the optical network units and a supervisory unit of cell overflow situation for detecting a cell overflow situation of a sending buffer of ATM cells in each of the optical network units; a bandwidth controller having a basic bandwidth assigner for assigning a basic bandwidth for sending ATM cells to each of the optical network units, an upper-limit bandwidth storage means for storing an upper-limit bandwidth set as upper-limit of bandwidth which is usable for transmission of ATM cells of each of said optical network units, a shared bandwidth assigner for assigning a shared bandwidth which is usable with the basic bandwidth to each of the optical network units according to value of the upper-limit bandwidth based on a receiving bandwidth and cell overflow situation that were supplied from said traffic supervisory unit, and the shared bandwidth storage means for storing the shared bandwidth assigned to each of the optical network units by said shared bandwidth; and a generator of access permission for generating access permission to assign optical network units according to the shared bandwidth assigned by said shared bandwidth assigned, wherein said supervisory unit of said cells overflow situation comprises an invalid cell detector that detects invalid cells received from each of said optical network units based on predetermined conditions and judges that the detected invalid cell is in the cell overflow situation in a case where the invalid cell was not detected by the optical network units.