I want to cut down my monthly Comcast bill and one part of the bill be a monthly rental fee for the cable modem . Amazon have several DOCSIS 3.0 modem available , but I could not see any substantive difference in they , so I go with the one just like what Comcast provide to cut down on potential issue . this one work fine out of the box ; I just have to call Comcast and give they the MAC address print on the bottom of the modem -lrb- I actually have to give Comcast the MAC address again when I return the rent modem , but that be a Comcast fail -rrb- . the ubee work just like what I have before , with no monthly rental charge , so I be happy .