| 摘要 |
PURPOSE: An apparatus for demultiplexing ATM cells using a dual port memory is provided to store, demultiplex and transmit cells using a dual port memory in order to prevent cell delay, which can be generated in a structure sharing a memory buffer, or data loss, which can be shown when a fault is generated in a specific channel. CONSTITUTION: An apparatus for demultiplexing ATM cells using a dual port memory consists of a dual port memory(10), a subscriber channel unit(20) and an interface control unit(30). The dual port memory(10) receives and stores ATM cells to be transmitted to the subscriber channel unit(20) from a cell bus. The subscriber channel unit(20) receives the ATM cells stored in the dual port memory(10) and executes UNI processing and line interfacing. The interface control unit(30) controls the flow of cells between the dual port memory(10) and the subscriber channel unit(20). The interface control unit(30) is comprised of a cell bus monitoring part(31), a left port address generation part(32), a subscriber channel interface part(33), a right port address generation part(34) and a channel cell counter part(35). The cell bus monitoring part(31) monitors whether a cell to be transferred to the subscriber channel unit(20) is on the cell bus. The left port address generation part(32) generates an address of the dual port memory(10) of a side to write cells from the cell bus. The subscriber channel interface part(33) checks the status of each subscriber channel to judge the possibility of cell transmission. The right port address generation part(34) generates an address of the dual port memory(10) of a side to read cells from the dual port memory(10) and to transmit the cells to relevant channels. The channel cell counter part(35) counts the cells of the dual port memory(10) by channels and notifies information and availability for the cell storage status of the dual port memory(10).
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