Connection Problems

There is a variety of internet devices in the house, any number of which are unused and could go wrong, and my Playstation decides that it's going to be the one to have a serious falling out with the router.

And I'm having trouble getting both PS3s to play online at the same time. Unless connecting to the same server (eg, together like we do on BFBC2 or MW2) one or the other lags like hell.
It's really annoying!