Introduction - If you have any usage issues, please Google them yourself
Reliable UDP data transfer. GBN algorithm used to realize: 1. Then packet loss (random number generator Math.random ()) 2. After the case of redundant packet loss retransmission ack 3. Retransmission timeout (DatagramSocket and Socket has a member function setSoTimeout ( delay), by capturing the IO exception thrown during timeout to achieve retransmission timeout)