Okay xbox live hlp?

On my xbox 360...i need help playing xbox live...i am connected wirelessly to my router....i test network connection and xbox live conenction and every p tests...i can easily sign into xbox live and talk with friends via message...but i can't talk to them...everytime i try it says it could not carry out the process...and everytime i try to join a friend it says.could not join the session in progress...and when i try to play live on my own, it says you must have an active network connection to play online....and sometimes it even randomly signs me out>???what is the problem somebody please help is it my router ?or what ...Router =Netgear Rangemax Wireless-N Router WNR834B...please help.