number portability ^*

• 9 kasım 2008'den itibaren türkiye'de de başlayacak olan 10 haneli cep telefonu numaran aynen değişmeden bir operatörden diğerine geçmeye verilen gavurca isimdir. türkçesi numara taşınabilirliğidir. iyi bi şeydir. fiyatlar düşer filan...
• https://en.wikipedia.org/wiki/voice_over_ip
  
  "local number portability (lnp) and mobile number portability (mnp) also impact voip business. in november 2007, the federal communications commission in the united states released an order extending number portability obligations to interconnected voip providers and carriers that support voip providers. number portability is a service that allows a subscriber to select a new telephone carrier without requiring a new number to be issued. typically, it is the responsibility of the former carrier to "map" the old number to the undisclosed number assigned by the new carrier. this is achieved by maintaining a database of numbers. a dialed number is initially received by the original carrier and quickly rerouted to the new carrier. multiple porting references must be maintained even if the subscriber returns to the original carrier. the fcc mandates carrier compliance with these consumer-protection stipulations.
  
  a voice call originating in the voip environment also faces challenges to reach its destination if the number is routed to a mobile phone number on a traditional mobile carrier. voip has been identified in the past as a least cost routing (lcr) system, which is based on checking the destination of each telephone call as it is made, and then sending the call via the network that will cost the customer the least. this rating is subject to some debate given the complexity of call routing created by number portability. with gsm number portability now in place, lcr providers can no longer rely on using the network root prefix to determine how to route a call. instead, they must now determine the actual network of every number before routing the call.
  
  therefore, voip solutions also need to handle mnp when routing a voice call. in countries without a central database, like the uk, it might be necessary to query the gsm network about which home network a mobile phone number belongs to. as the popularity of voip increases in the enterprise markets because of least cost routing options, it needs to provide a certain level of reliability when handling calls.
  
  mnp checks are important to assure that this quality of service is met. handling mnp lookups before routing a call provides some assurance that the voice call will actually work."