| 摘要 |
PURPOSE: A multicasting service system and a method in an ATM switch is provided to offer a multicating service like a picture conference among a plurality of subscribers belonging to the same physical line by installing two FIFOs at the same physical line. CONSTITUTION: A multicasting service system comprises a 1st memory(22), a 2nd memory(23), a VPI/VCI(Virtual Path Identifier/Virtual Channel Identifier) conversion/cell copying circuit(11), FIFO1s(24-1,n), and FIFO2s(25-1,n). The 1st memory(22) stores a table on VPI/VCI conversion values in relation with broadcasting cells transmitted to each subscriber via different physical lines. The 2nd memory(23) stores a table on VPI/VCI conversion values in relation with broadcasting cells transmitted to each subscriber via the same physical line. The VPI/VCI conversion/cell copying circuit(11) converts the VPI/VCI value, read from the memories(22,23) according to the service characteristics of a transmitted ATM cell, into the VPI/VCI, and copies the correspondent ATM cell. The FIFO1s(24-1,n) transiently stores one cell among cells transmitted to subscribers via the same physical line from the VPI/VCI conversion/cell copying circuit(11). The FIFO2s(25-1,n)transiently stores the remnant cells among cells transmitted to subscribers via the same physical line from the VPI/VCI conversion/cell copying circuit(11).
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