So what is a phone numbering plan? It is in fact a plan of allocating international phone numbers to cellular providers of the whole world and the points of various countries, areas and districts. There’s still a difference between international dialing codes and numbering plans. Or there can be a closed numbering plan applied in places like Canada or Australia. For closed plan it is supposed that there are local phone numbers with appointed length area codes.
An open numbering plan denotes that numbers and dialling codes can be different subject to the country and district they belong to. This numbering plan functions in a number of countries today. Dialling the telephone numbers fixed by this system you should be sure to always dial the figures of the local number, while the units of the area calling code don’t need to be always dialed.