What is a Network Rack?
A Local Area Network (LAN) is comprised of multiple networking equipments like network switches, routers, UTM appliances, Servers, patch panels, cables, modems, etc. These equipments are generally kept inside a network rack, which is a closed or open enclosure that can hold them. The size occupied by networking hardware equipments follow certain industry standards so that they could fit in to the network racks, which too follow those standards. The common width of a network rack (and the networking equipments) is 19″ (Inches) – most of the racks are made to accommodate any equipment that can fit in to this space. Also, the networking equipments have fixed heights that are mentioned in terms of Rack Units.
So, if a networking equipment is specified as 2U, then it has a height of 3.4 inches (approx). So, if one has the sizes (In RU) of all the networking equipments that needs to be placed in a rack, the required height of the Rack (in RU) can be easily calculated as the sum of the heights of all the individual equipments – generally slightly more than that, in order to accommodate the networking equipments freely in the rack and also to provide for future expansion.