is UPnP all about port forwarding?

Hello everybody.

I have a ps3 console which always states that UPnP is unavailable no matter what I do -I guess its because of the modem-.

However, I have already opened all the ports to my console (via setting DMZ mode). But, I am -most of the time- having problems connecting with my friend across games like Boarderlands and Modern Warfare 2. The common error message was "Connection timed out".

My question is: Does UPnP have anything to do with the PSN beyond the auto portforwarding? or my modem/service just suck :P?

I appreciate all the help you guys give me :)

and sorry for any English mistakes. It's not my first language obviously :D.

1) Are you connected directlyto the modem, or through a router/switch?

2) If you're using a router, is it allowing UPnP? Is the firmware updated on the router?