Patent ID: 7142515

Claim:
Data transmission system comprising: a packet switch module comprising a plurality of input ports and a plurality of output ports; and a memory block ( 200 ) located at each crosspoint of said switch module, wherein each couple of one of said input ports and one of said output ports defines a crosspoint, said memory block including memory control means ( 210 , 212 , 234 ) for determining from the header of a received data packet whether said packet is to be forwarded to the output port associated with said crosspoint; and a data memory an it ( 226 ) for storing at least said data packet into said data memory unit before sending it to said output port, wherein said memory control means analyzes all the bytes following said header when said header includes a specific configuration indicating that said packet is a multicast address packet preceding a multicast frame, said multicast address packet including information describing a plurality of destination output ports for said multicast frame, wherein said all bytes following the header are analyzed in order to determine, without the use of a routing table, whether the packets of said multicast frame are to be forwarded to said output port associated with said crosspoint.