An upload speed of 1 mbps from the network where your SB-HD is attached would probably be adequate for streaming standard definition video, but probably not fast enough for streaming high definition video. For high def, you would want to have upload speeds of at least 4 mbps. You might check with your Internet Service Provider to see if they can increase your upload speed without charging you a whole lot more in monthly fees. Sometimes, the cable connecting your modem to the outside world could be weak -- for example, if there are a lot of splitters or filters or a not-tight-enough connection in the system. I doubt that the router is the culprit, and most likely not the cable modem either. But Comcast should be able to test -- and my Comcast techs can even do the test remotely -- to verify the strength of signal reaching your modem and what upload speeds should be achievable.