A rack houses up to four rack mountables such as servers, terminal servers and mountable disk drives. Connectivity of mountables in a rack can be configured in detail via the GUI. In particular, if servers contain components that support it, such as network cards, network-only connections can be defined for those components. These connections will serve purely for passing along network messages, components will not be visible through them. Such network-only connections are differentiated by the lines being slimmer than the "main" connections, which also allow component access. Each internal connection must be between a mountable / component in a mountable and a bus connected to a side of the rack. To connect multiple mountables to each other, connect them to the same bus.
Racks also act as relay and power distributor in one. Whether it acts as a relay or not can be configured in the rack's GUI, it being enabled being indicated by a connector line between the side buses.