We use xilinx xaui core in our Ethernet design, we choose XGMII as our internal interface. And now, I am confused. I found that the data between START(0xfb) andTERMINATE(0xfd) will all be transmit through XAUI. So, if we use xaui core in Ethernet design, do we need to transmit preamble, sfd and FCS? Now, I think may be we need preamble and sfd to meet XGMII standard, but what about FCS. In 802.3ae chapter46, it said CRC is done by RS.Please help me to make sure frame format, Thank you!