Sunday, November 24, 2013

File Transmission needs reliability! Why TFTP works on top of UDP, though?

By definition User Datagram Protocol (UDP) is an unreliable protocol! It doesn’t provide any error checking or correction, no whatsoever! So what makes a sensitive application such as TFTP use it?

Simply, because UDP is simple! There’s no overhead using UDP. On the other hand TFTP was designed to be very lightweight, and using TCP will overcome this advantage.
We still need some kind of reliability! No?

SURE! What TFTP does is that, it uses its own “rudimentary” reliability mechanism, in which an “ACK” will be sent for each received block (i.e. packet), and any “non-ACKed” block will be resent again. This mechanism is called “Positive Acknowledgement with Retransmission”.


A good video to watch:


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