Interface Protocol VIP

In reply to chr_sue:

What determines what the driver should drive?

Assume that I have two agents, master and slave and an interface in between.

Master sends a request, I receive it monitor, and subsquently drive the appropriate response. My question here. what determines what should be random? response shouldn’t be random. however what are the attributes that should be randomized?
For examlple, assume a read request, should the slave be randomized to emulate a real life behaviour of a memory for example? where it might be busy, or slow, or fetching some info from another chip for exampe. should this be randomized?