P2p is cool, stylish, fashionable and youth. Have the address and port all your contacts, communicate directly. However, the main difficulty is to obtain a list of their contacts. To do this, one way or another the required servers to start. You turned on the phone, he does not know about any of the neighbour. He needs to go somewhere to get an actual list of feasts. This is the place (or places) should be conditionally constant. It will block (fail) - will block all of your p2p network.