currently in the P2P field, only using STUN (not use Turn Server) hole punching success rate is what?

Question

I would appreciate you did a great job here, if you could help me answer the following questions:

1. In the case of large scale and various NAT type devices, currently in the open source code field, only using STUN (not use Turn Server) punching success rate is what?

2. In addition, is there any way to increase the success rate of hole punching to 99% In the case of stun only(not turn)? E.g. port prediction

3. If there has turn server, whether can make the success rate of the hole punching reach to 99.99% above?

Thanks to anyone who can give me an idea for any question!

Answer 1

As for NAT types, we always means the four types(also named as NAPT): Full Cone, Restrict, Port Restrict, Symmetric. For Symmetric NAT, it's relatively hard to do hole pounch. For the other three types STUN can solve them easily. So it's hard to say the success rate for all of them.