When wiring an IC layout, the only way to get a signal from one point to another is to physically place the wires. Signals that span a large circuit, such as power and ground, must be carefully wired together at each level of the hierarchy.

In schematics, however, it is often the case that a signal is used commonly without specially being wired or exported. Examples of such signals are power, ground, clocks, etc. The power and ground signals can be established in any schematic with the use of the Power and Ground nodes. To create another such signal, use the Global node of the schematics technology (see Section 7-5-1).

The Global node is diamond-shaped, and it has a name and characteristic similar to exports (input, output, etc.) All signals with the same global name are considered to be connected when netlisting occurs. Thus, the Global symbol can be used to route clock signals, as well as to define multiple power and ground rails. Note that with multiple power and ground rails, only one of them is the true "power and ground" as defined by the Power and Ground symbols. All others, declared with Global nodes, are not true power and ground signals, but are simply globals.