Overcoming the challenges of Number Portability implementation

A lot has been made in the news lately of the success of Number Portability in Ghana. A recent report released by the NCA contains details the success of Number Portability in its first year (see below).

Over 370,000 numbers were successfully ported and Ghana is one of the few African nations to have successfully launched the service in the time that was first set out. It is only the second African country, after Kenya, to achieve this, although Nigeria, Egypt and South Africa have also been working on it for some time.
The overall performance and porting time in Ghana compares pretty favourably against other recent Mobile Number Portability implementations such as Kenya, where it could take 48 hours to port your number, and in India, where porting a mobile number could take up to 7 days.

http://www.nca.org.gh/documents/News/MNP_in_Ghana_First_Year_Report.pdf

But why is it so difficult for some countries to implement Number Portability in the time taken? Why do some seem to be able to have a smooth and efficient implementation while others don’t? What are the challenges posed by MNP implementation and why do some countries seem to struggle with these issues more than others?
Is it due to the infrastructure, technology and system upgrades that are needed? Is it more of a political issue? Some say that in countries where democracy is still a relatively new introduction, the introduction of Number Portability can often have political connotations. Some countries have a very involved NRA which really drives and steers the whole process, while others don’t.
What are your opinions and what do you think are the toughest challenges posing new countries that will implement Number Portability soon, such as Azerbaijan, Botswana and Costa Rica?

Number Portability Global Summit – 22-24 October 2012, London, UK. View the Full Agenda.