A rack also called an equipment rack, is a metal frame for holding and organizing networking devices. A networking component that is designed to be mounted in a rack is said to be rack-mountable. Rack-mountable devices include hubs, routers, Ethernet switches, patch panels, and uninterruptible power supply (UPS) devices.
Racks can be wall-mounted or freestanding. They come in various heights and standard widths – 19 inches is by far the most common width. The width is the distance between the mounting holes for mounting equipment – the actual width of the rack is usually several inches wider. Common heights for racks are 48 and 83 inches.
In EIA/TIA-compliant racks, the holes on the frame are spaced 1.75 inches apart vertically, a distance symbolized as a “U” or “unit” of rack space. If a piece of networking equipment is described as 3U, it occupies 3 x 1.75 = 5.25 inches of vertical space once it is mounted in the rack.
Racks offer a way to organize equipment in a wiring closet. Racks come with a variety of accessories. Cable organizers, for example, allow you to run bundled cabling down the side or back of the rack to avoid “spaghetti.” You can use sliding shelves or drawers to incorporate odd-sized equipment in racks for easy access for configuration and wiring. Vented sides and fan trays help circulate air to keep equipment from overheating. By attaching a locking plastic door, you can convert some racks into cabinets for more secure storage.
A ladder rack is a modular rack system for supporting cable runs in walls, false floors, and false ceilings.
If your area is prone to earthquakes, you can bolt the base of your rack to the floor for greater security. Wall-mounted racks allow you to organize equipment in areas with limited floor space.