How can i setup a wireless LAN that can serve up to 20,000 concurrent devices. I am having a problem in figuring out if i need one router or several routers. A topology diagram with explanation would be very very much appreciated. Thanks in advance.
Depending on the usage profiles, you can support between 10 (serious) and 100 (very light) users per WAP. Since that means 200 to 2000 access points, you'll likely want a managed, controller-based solution with central RADIUS authentication.
The WAPs need to be uplinked by a sufficiently fast switch fabric, again depending on the expected overall load.