NetConnection

The NetConnection class creates a bidirectional connection between a Flash Player or AIR application and a RTMP application or between a Flash Player or AIR application and an application server running Flash Remoting. A NetConnection object is like a pipe between the client and the server. Use NetStream objects to send streams through the pipe.

See http://livedocs.adobe.com/flex/3/langref/flash/net/NetConnection.html