Loss of internet connection

[sparky]

While connected to the internet, I take a break and listen to songs on iTunes, sometimes for an hour or more. When I go back to  browse the internet again, my connection is lost and I must restart. How do I extend the period of time before I lose my internet connection? I have a cable connection, not dial up.
Thanks.

[Broni]

When connection is "lost", does ping command work?
What are exact symptoms of "lost" connection?
What browser?