In reply to chr_sue:
Thanks for the example chr_sue
Yes, in that scenario the use of one interface is clear to me. However my scenario is that I have a DUT(s) which process stuff in a pipelined fashion. I.e. in one side there is data in, at the other side data comes out. The input and output side is almost the same except for some load and data_ready signals. Concretely, it is a SERDES system, where TX and RX DUTs are connected back to back. Hence the question of whether of using one or two interfaces here, as it is almost the same interface however each side actually belongs to different DUTs