What I'm wondering about is this: We have a Comcast modem with WiFi that is hooked up straight to the cable coming into one side of the house. We also have a new Airport Extreme which I connected to the router with a long Ethernet cord so I would be able to have strong WiFi on the opposite side of the house (we also have an older Airport Extreme which I use to wirelessly extend the signal into the yard, but that's not relevant to this discussion I think). What I wonder about is this: is there a way to configure the Comcast modem and the new Airport Extreme such that my devices (phone, tablet, laptop) will switch network automatically as I go from one side to the other of the house? I know that the two Airport Extreme's trade off supplying the devices automatically, but I don't know if the same can be done between the modem and Airport extreme attached to it via ethernet. Thanks for any advice you might have.