I know the algorithm for pong.

But my brother is better, he knows Ping Pong. Serioulsy, he learned it when he was at University and now he teaches gymnastics at schools

Thats real funny JavaAddict

Before you start u need to do this:
First create a client server app
you need to also create your ping protocol

your classes should be like this
PingClient, PingProtocol and PingServer

Now here's your algorithm
send a ping request to your server i.e
ping [server-ip-address]
recieve the request on the server side
compare the ip-address with the server's ip-address
if they match send an acknowledgement back
if not have the client timeout