When running STUN over UDP, it's possible that the STUN message might be dropped by the network. Reliability of STUN request/response transactions is accomplished through retransmissions of the request message by the client application itself.
A client should retransmit a STUN request message starting with an interval of RTO ("Retransmission TimeOut"), doubling after each retransmission. The RTO is an estimate of the round-trip time.
By default, the sgcWebSockets STUN Client is already configured with a RTO of 500 ms and a Max Retries value of 7.
For example, assuming an RTO of 500 ms, requests would be sent at times 0 ms, 500 ms, 1500 ms, 3500 ms, 7500 ms, 15500 ms, and 31500 ms. If the client has not received a response after 39500 ms, the client will consider the transaction to have timed out.
TsgcSTUNClient oSTUN = new TsgcSTUNClient();
oSTUN.Host = "stun.sgcwebsockets.com";
oSTUN.Port = 3478;
oSTUN.RetransmissionOptions.Enabled = true;
oSTUN.RetransmissionOptions.RTO = 500;
oSTUN.RetransmissionOptions.MaxRetries = 7;
oSTUN.SendRequest();