[flexcoders] Socket communications in Flex

[markgoldin_2000]

I am trying to understand how socket communications work in flex.
This code will connect to a port 8080 on a local computer:

var xmlsock:XMLSocket = new XMLSocket();
xmlsock.connect("127.0.0.1", 8080);

But what I dont understand is what would be sending data to that 
port? 

Thanks