Thank you a lot for your very good explanation in Bangla. This video has helped me a lot to understand something more clearly. As well as it is really a very good initiative to teach science in Bangla language which will help many of us like me a lot. By the way, in "Retransmission", if a packet is lost somehow and the sender does not get the ACKs according to it then the retransmission process will happen. like for TCP/IP, if the sender gets 3 duplicate ACKs then it takes into account that the segment is lost then start the fast retransmission process. So, as I know 'retransmission' happens after the 'Acknowledge' process. If I am wrong please feel free to give me some ideas according to this. Thank you again.