To understand how Wf-XML works, let's say your company needs to build a server farm for a new interactive media service. You probably need to develop internal requirements and constraints and review them with various parties who are responsible for product management, finance, and application development. Each vendor that receives your RFP has its own internal process for delivering a proposal, which involves at least one salesperson and one system engineer. When you receive the proposal, you have your own review process, which may include inviting the top vendors to make in-person presentations. Once you decide, you probably submit some paperwork to your purchasing coordinator together with a copy of the vendor proposal.
Someone writes up a purchase order and delivers it to the vendor.
At this point, the vendor's internal systems take over, initiating several processes to obtain hardware and software and assemble them according to the promised configuration. These processes may in turn generate orders for computers, software, and other components from upstream vendors. If all goes well, the vendor delivers the proposed system on the requested date. At the same time, the vendor's accounts receivable department generates an invoice and delivers it to your accounts payable department. If the vendor has given you terms, it's possible that the vendor will factor the receivable.