What is Mobile Number Portability ?

Mobile number portability (MNP) enables Mobile Phone users to retain their mobile telephone numbers when change from one mobile network operator to another network. Mobile users easily opt their best Network using Number portability service.
MNP now implemented in many countries on the Globe. Tariff charges to transfer number from one operator to another operator is applicable.
Mobile Phone Consumers Portability :

In many countries paid transaction fee by subscriber gained network. In India expect the tariff Rs.200 to 300 and not finalised. MNP may introduce before end of 2009 in India.
Department of Telecommunications (DOT) issued licence to Two Telecom MNP players to provide service in India. These two players provide service separately in two circles. TRAI ( Telecom Regulatory Authority of India) may announce tariff details before introducing Mobile Number Portability in India.
Major Disadvantage of Mobile Number Portability (MNP) is Easily can't identify the Network of the Mobile Number. OK be ready to enjoy the benefits or Advantages of MNP when implemented.