I buy this because Charter recommend upgrade to a docsis 3.0 modem for better performance and this seem to be the best -lrb- costliest -rrb- available . disappointment ! installation be not smooth . on replace the modem , Charter could not restart the modem remotely , so I have to do it manually . that itself do not seem right . I see a slight speed improvement compare to my 5-year old modem , though nothing to justify the 95 buck I have shell out for this . after a week or so , it just disconnect and I could not get it to re-connect . Charter detect some bad signal come from the modem . I go back to my Ubee old modem which work fine . after a day later , hope that it be just a temporary glitch , I install the sb6121 again and it work fine for another week after which it again just disconnect . it be as if it need a day off every few day !! I can not afford to give pay vacation to modem , so I ditch it and return it to Amazon .