| 摘要 |
For terminating an Asynchronous Transfer Mode (ATM) multiplexed data stream at a functional unit, where virtual channel data not including a frame alignment signal is carried in cells each having a message sequence number; a cell aligner having a plurality of cell buffers each storing the payload data contained in a single cell, the cell buffers being conditionally loaded in accordance with lower significant bits of the message sequence number provided the message sequence number does not correspond to the message sequence number of the cell buffer being depacketised and is not more than a pre-determined number of message sequence numbers in advance of the cell buffer being depacketised or an empty cell buffer being replaced by a fill-in cell and the cell buffers being emptied according to the conditions of a combined depacketiser and slip algorithm to form a continuous data stream aligned to the clock and frame start signal of the functional unit; the cell aligner further having a fill-in cell format generator which on the failure of a valid cell to arrive causes the replacement of the missing cell by a fill-in cell in the continuous data stream and a time-out function which is cleared and restarted after each valid cell is received in order to cause a restart of the combined depacketiser and slip algorithm if it should mature. |
