Question

• Read the following problem.
• Use your knowledge about the Inclusion-Exclusion Principle to support your criteria.

Telephone numbering is an application of the inclusion-exclusion principle. Discuss with your peers a way in which the current telephone numbering plan can be extended to accommodate the rapid demand for more telephone numbers. (See if you can find some of the proposals coming from the telecommunications industry). For each new numbering plan you discuss show how to find the number of different telephone numbers it support.

Answer 1

Answer:-

A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined in each of administrative regions of the public switched telephone network (PSTN) and they are also present in private telephone networks. For public number systems, geographic location plays a role in the sequence of numbers assigned to each telephone subscriber.

Numbering plans may follow a variety of design strategies which have often arisen from the historical evolution of individual telephone networks and local requirements. A broad division is commonly recognized, distinguishing open numbering plans and closed numbering plans. Many numbering plans subdivide their territory of service into geographic regions designated by a prefix, often called an area code or city code, which is a set of digits forming the most-significant part of the dialing sequence to reach a telephone subscriber.

The International Telecommunication Union (ITU) has established a comprehensive numbering plan, designated E.164, for uniform interoperability of the networks of its member state or regional administrations. It is an open numbering plan, however, imposing a maximum length of 15 digits to telephone numbers. The standard defines a country calling code (country code) for each state or region which is prefixed to each national numbering plan telephone number for international destination routing.

how to find the number of different telephone numbers :-

A numbering plan can be generally divided into open and closes numbering plans. An open numbering plan can assign various numbers of digits, while a closed numbering plan has a set number of digits. Numbering plans, in many cases, most significantly depend on the geographical zone of the subscriber: a fixed number of area codes is allotted depending on the state, city or region. Any user dialing from within a network must first specify the area code if dialing outside their local zone. Not only public switched telephone networks (PSTNs) but private telephone networks employ numbering plan schemes as well.numbers can find