Keep in mind that 10gbps copper maximum length is 100meters (sure it sounds like a lot but do you know the size of a data centre!?) Short reach data application distance is 100-300meters. So copper can only do the extremely short distances. Keep in mind that Bandwidth and speed are different in some ways and similar in others. Cat6 requires 4 twisted pairs and a termination resistor on each end of the twisted pair. If you have too many modules on the same network you get data crash - computers constantly are required to resend the packet if it detects that it wasn't recieved too many incomplete transfers and it will drop the packet entirely.