Presently, I'm running a wireless network which consists of an Airport Extreme and two Airport Expresses. The Extreme is on the main floor of a three level home.
Older Express is used to extend the wireless network, but it primarily functions as an Airplay device connected to speakers.
Newer Express is in the basement near the entertainment center. I configured it to wirelessly extend the network, in an effort to get better wifi reception to the various devices - PS3, Blu-Ray, AppleTV, AV receiver.
Wirelessly extending it works, but I know it's not the optimal situation. I'm exploring adding a new Extreme to the basement, wired to the current Extreme.
I referred to this Apple KB article which is very helpful. Running ethernet from the family room directly down to the utility room is easy. The basement/entertainment center is adjacent to the utility room.
From there, I have two choices.
Mount the new Express just outside the utility room, on the ceiling. Easy access to a power outlet and the ethernet cable can easily connect. After following the configuration directions, I should have a better wifi signal in the basement, for the fixed devices and occasional mobile devices. In this case, the two Extremes would be 25-30 feet apart, via a staircase. Do I need to address channel configuration? Or is using 'automatic' sufficient?
Run a longer ethernet cable into the utility room, and tack it along the baseboard. Set up the new Extreme alongside the devices for an optimal signal, or utilize any of the three LAN ports for direct wiring. In this case, the two Extremes would be 50-60 feet apart. Again, what do I need to do for the channel configuration?
In both cases, I'm likely adding in a switch, since all three LAN ports on the current Extreme are in use; I'll need one free port to wire to the WAN port of the new Extreme.