Connect Xdj 1000 mk2

Hi all, i have bought 2 xdj 1000 mk2 and mixer djm 750. I have macbook air and i will connect xdj's directly with usb. Do i need ethernet connection? if i need for what? Maybe for share Usb key if i don't use pc?

I need hub or i can use only ethernet cable? 

tnanks