Folding@home uses a client-server architecture. The software first asks the Assignment Server (which acts as a load balancer) for an available and appropriate Work Server. The Work Server then sends back a Work Unit (WU). A FahCore may also be downloaded from a Web Server, depending on the WU. The completed unit is then sent back to the same Work Server, with a designated Collection Server as a backup. Log files and credits are then collected from the Work Servers and passed to the Statistics Server for tabulation and display.