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

Telephone numbering system has some design strategies so that no one get the same number means unique number.This design strategies varies from country to country. For example :in India:

Landline format =area code+number

Mobile number = country code+10 digit number

As we know with the increase in technology, demands are also increases which need an extending plan

1)Relocating the existing numbers for paging services and re-allocating some of the numbers in the “7(0-3)X” levels for mobile services

2) Re-allocating numbers in the “4X” level for mobile services, which will be able to release5.6 million numbers to meet the demand

3) Re-allocating vacant numbers in the “8(1-3)X” levels for mobile services

4) Raising the threshold of utilisation rate for allocation of additional numbers to network operators, which will be able to release2.42 million numbers to meet the demand

5) Releasing most of the Special Number Blockss1for normal allocation, which will be able to release a maximum of 3.52 million numbers to meet the demand