Why mention Sisco here? The problems with Intel 6235 WLAN card have problems with many systems not connected to any Sisco router. I've tested the Intel 6235 cards for two weeks now and it has serious problems with all drivers I've tested. When I use a USB Asus N53 WLAN card the problems with connection drops disappear.
I have an all Intel set, Intel NUC i5, and have still problems with the n6235 card. It's obviously a crappy card that Intel released without any thorough testing.
So much for "Intel Inside"...