Please don't come on here telling me how PS3 sucks and how i should get a Xbox360.

Hey guys i need some help. I can't seem to be able to get online to play multiplayer on Call of Duty or Rainbow 6. Everytime i try to find a match or anything it signs me out of the online network. I'm able to go onlne and surf the web and never get signed off but as soon as i try to play online i get kicked off. I have a linksys G router. Can anyone give me some info please. Thanks