i want to get a network device working as a multiplexer.
for example, only the data sent to port A would be forwarded to port B completely. and the data of port B have to be forwarded to port A also. it seems like there is a virtual twister line between port A and port B.
after some configuration, i can dismiss the virtual line of A<=>B. the other virtual line C<=>B can be established.
i need four separate virtual lines described above concurrently. also 20 ports are a base line.
the first solution comes to my mind is a switch with VLAN. but VLAN would involve some tags. any good idea or switch model suggestion?(1Gb ether needed)