Jed is opening th conversation by greeting Andrew. His question "what's going on?" is still at a rhetoric level, because there is something that he wishes to communicate to Andrew. Andrew, in turn, provides feedforward in asking "You?" By asking this, he is paving the way for Jed to introduce the business, that is, the subject matter of the conversation; in an implicit way, Andrew is asking Jed: "what is it you wish to talk to me about?"