Roaming interupts Internet Connection

[PanaromicTiger]

I've got an Asus RT-N66U as my main router and a TL-WDR3600 as additional AP.

I've configured the Asus as the DHCP server and there is a LAN 2 LAN connection to the WDR3600. While roaming the client will connect to the WDR3600, but the internet connection drops for about 15 minutes.

Did i buy the wrong AP? I mean will it work with a secondary Asus AP?
Or is there something else?

 

[sfx2000]

on the TL box - disable the DHCP server, give it a static IP on the same subnet as the rest of the network, but outside of the DHCP scope, and plug the ethernet into the LAN port, not the WAN port.

common SSID's/Auth Keys for both...

should work...