Netowrk Disconnects when idle

ISP: Comcast Cable
Router: Duolinks SW24
AP: Cisco WAP 4410N
OP: Vista Ultimate

When I leave my computer idle, it disconnects after 5 minutes or so and the computer can not be pinged. I have disabled the following so far:

System Power Managment
Hardware Power Management
All sleep/hibernate for system and hardware
Set 'net config server /autodisconnect:-1'

If I keep something running like pandora.com, then I wont get disconnected. So I want to blame it on Vista for another setting that has 'disconnect when idle' or the sort that I just havent found.

Now for the screwball.. when I use my Linksys WRT120N wireless router, the connection stays alive indefinitely... or at least 10hrs that i tested. So now, I have the blame the fault on the Duolinks Router or Cisco AP, but I cant find any configuration that has to deal with idle timeouts. I also cant figure out of the Linksys (working) router has some sort of keep alive function that the Duolinks does not..

Please let me know if you have any ideas...