When I'm wirelessly and establish a VPN session using Cisco AnyConnect VPN client my wireless connection goes down and I see that red "X" just like if there was no signal. Upon quitting the VPN client, wireless immediately comes back up.
Have you ever seen a similar issue before ?
I've seen this type of issue when the VPN driver/supplicant on the client is mapped to multiple interfaces and is also configured to only use one at a time. For example, CSSC by default runs on all interfaces (wired and wireless). With the default behavior when you are connected to the wire the wireless is not available.