| 摘要 |
PURPOSE:To check whether a transfer is permitted for a packet to be inputted in a packet switching or a packet to be outputted. CONSTITUTION:A transmission origin address and a destination address for which transfer are preliminarily permitted are set in an associative memory circuit 4. An address extraction circuit 2 extracts the transmission origin address and the destination address from a packet and endows a comparison control circuit 3 with them. The comparison control circuit 3 checks the presence or absence of the coincidence after these two addresses is endowed to the associative memory circuit 4 as comparison data. If the associative memory circuit 4 outputs a signal showing the coincidence, the packet is to have the permitted address. The comparison control circuit 3 notifies it to a gate circuit 5 by a permission signal 12. The packet is inputted in a packet switch 7 via the gate circuit 5. The same operation is performed for the output from the packet switch 7.
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