| 摘要 |
An ATM switch with multicast capability is provided that internally uses input and output identifiers to identify the cell input and output streams, the relevant input identifier being generated for each cell as it arrives. The apparatus has a store for storing both the cell bodies of the cells received by the apparatus and queue data (171) serving to identify in first-in-first-out order, the cell bodies to be output on each output stream. The apparatus is further provided with a send-control subsystem including a scheduling loop (75, 77, 172) and an injection block (82) for injecting output identifiers into the scheduling loop in response to the arrival of new cells. The scheduling loop effects output scheduling of the output streams on the basis of the output identifiers and indicates the next scheduled output stream by outputting the corresponding output identifier, thereby removing it from the scheduling loop. An output unit (64) receives the output identifier of the next scheduled output stream from the send-control subsystem and uses this identifier to retrieve the corresponding cell body from the store. The output unit then outputs this cell body on the scheduled output stream. The send-control subsystem can also be used in systems handling variable-length packets. <IMAGE> |
