I have a couple MTK MT7621A units that I have setup as dumb ap's using this little script:
Works like a charm, and everything all devices can talk just fine to each other on my network. My question, should I have both 2.4/5Ghz bands ssid's named different on each AP, or keep all the ssid's on all my openwrt devices the same? For instance, if I put one device on each floor (hard wired) would cell phones and laptops bounce back and forth between devices on each floor if the ssid's were the same?
From my experience the clients can be quite stubborn and stick to the AP they connected, rather than switch to a stronger signal.
I had to tweak minimum rssi to be able to roam properly.