In large commercial buildings I typically see several ceiling mounted Wireless Access Points. When moving throughout the building, I do not have to continually reconnect to different networks (or SSIDs).
I assumed this is what WAPs do: You plug them into your Router or Switch and they create a wireless network. You would then give the same SSID from your existing wireless network and you would have a larger, better network.
However, posts such as this make it seem like each WAP may need to have its own SSID.
If this is the case - how do large commercial businesses create large, non-mesh wifi networks?