Hi Khoa Pham. Hi all who wants to know what ICE is. This is beautiful awesome video which completely clearly understandable says WTF is this ICE (this video is related not only to VoIP): >>>? http://www.youtube.com/watch?v=9MWYw0fltr0 ?<<< >AFAIK, ICE is used to detect as many ways as possible to send media stream to the other client. If it can't find, it will use TURN protocol to determine media relay proxy. Yes >How can ICE detect many ways? ICE is based on two protocols: STUN and TURN. STUN is designed to determine is there NAT and what type this NAT has. TURN is designed to transfer data when other ways fails. In short: At first (i. e. at beginning of ICE session), both sides connect to STUN server and determine is there NAT. And what type this NAT has. If they figure that there is way to connect directly (for example, both has no NAT or one has NAT and other has no NAT), they will connect directly. If they figure they cannot connect directly (for example, both sides has symmetric NAT), they use TURN. "Many ways" means: 1. A connects to B via TCP 2. B to A 3. They use ICE 4. (maybe some other ways) > Can we benefit from ICE if we're in symmetric NAT? Yes. But in this case you need TURN server. Askar Safin
