I need to know what IOS software to downloan to configure Q-inQ on a Cisco 2600 series router.Thanks!

I would like to know how the Pix running version prior to 7.x process a packet with qos marking. I am pretty sure the pix will not honor the qos, but what it does to the packet, strip off the qos?, or ignore it?. The same with version 7.0 and how abo...