| 摘要 |
<p>In a communication network where IEEE-1394 nodes are connected to a serial bus, each node functions as a source or a destination for signaling an asynchronous channel setup request containing a multicast address and signaling an asynchronous channel release request. A multicast manager, connected to the bus, includes a channel allocation table having a number of entries each mapping a channel number to a multicast address. The multicast manager responds to the setup request for making a search through the allocation table, setting a node count value to 1, acquiring ownership of a channel number from an isochronous resource manager and mapping the acquired channel number to the multicast address of the request in a corresponding entry of the allocation table if no channel number was mapped to the multicast address or incrementing the node count value by 1 if a channel number is mapped to the multicast address, and then signaling a reply message. The source node responds to this reply message by multicasting asynchronous stream packets to the serial bus. The multicast manager further responds to the asynchronous channel release request for decrementing the node count value by 1. When the node count value equals zero, the ownership of the channel number is restored to the isochronous resource manager and the corresponding entry of the channel allocation table is cleared. <IMAGE></p> |
