Not a problem. Jumbo frames will mix with standard frames. I have gigabit switches that support jumbo frames, and all my stuff is connected to those. My router happens to be the Verizon FiOS supplied MI424WR and it only has 100mbit ports anyway. I have machines that have 100mbit NICs, and of course the wireless connections. Neither of those support jumbo frames, and they talk to the NAS just fine.