So for a project I have to implement rdt in java using a simulator that has already been coded for me, I just have to do the sender and receiver classes (entities). This is a diagram of what is happening. But whenever I try udt_send(packet) or rdt_send(packet) I get an error 'cannot find symbol' for rtd and utd. I presumed it was a pre-set thing in java but evidently not, any ideas of what I'm supposed to do with this or how the rtd or utd is meant to work? Thanks guys.
p.s. Only unidirectional transfer of data is required.
