Yes, most often.
TCP is being used at the time being. UDP Support is still being developed in flash.
DNS uses both TCP and UDP, also a lot of online chats use UDP. I think even when you want videos on YouTube UDP is used to deliver video and audio.
UDP and ports 67 and 68.
UDP is a connectionless protocol, so there is no session to close. UDP is not expecting any particular packet, so opening and closing via UDP is not necessary.
Aknowlagement
Yes, it does.
TCP
You don't need to configure UDP; this is done automatically by the application protocols that use this transport method.
UDP is alot faster than TCP. So if its realtime obviously it has to be fast, thus UDP. The only problem is UDP isn't as reliable or as secure as TCP. But it does have the speed advantage.
No it uses UDP packets.
UDP does not require as much resources as TCP but in the same time, it does not insure delivery of packets.
138