[2] In the United States and Canada, mobile number portability is referred to as WNP or WLNP (Wireless LNP).
[4] Wireless number portability is available in some parts of Africa, Asia, Australia, Latin America and most European countries including Britain; however, this relates to transferability between mobile phone lines only.
The government of Hong Kong has tentatively approved fixed-mobile number portability; however, as of July 2012, this service is not yet available.
Though it was introduced as a tool to promote competition in the heavily monopolized wireline telecommunications industry,[6] number portability became popular with the advent of mobile telephones, since in most countries different mobile operators are provided with different area codes and, without portability, changing one's operator would require changing one's number.
Some operators, especially incumbent operators with large existing subscriber bases, have argued against portability on the grounds that providing this service incurs considerable overhead, while others argue that it prevents vendor lock-in and allows them to compete fairly on price and service.
Due to this conflict of interest, number portability is usually mandated for all operators by telecommunications regulatory authorities.
As of late November 2003, LNP was required for all landline and wireless common carriers, so long as the number is being ported to the same geographical area or telephone exchange.
With phone numbers assigned to various operators in blocks, the system worked quite well in a fixed line environment since everyone was attached to the same infrastructure.
When the Old Provider receives this request, it sends back Firm Order Confirmation (FOC) and the process of porting the number(s) begins.
Either provider can initiate the port using a Service Order Activator (SOA or LSOA) which directly edits the NPAC database mentioned before.
[13] A fax machine connected to its own physical telephone line at the subscriber's premises is portable in the same manner as any other standard wireline service.
In Canada, pocket pager answering services are exempted from all local number portability requirements.
The same is not true of mobile telephones, which are fully portable to another carrier or another service type (such as landline or voice over IP) within the same local interconnection region.
In March, 2009, the Dominican Telecommunications Institute (INDOTEL) selected Informática El Corte Inglés to administer the number portability.
[24] The Federal Commission of Telecommunications (COFETEL) applied this law, in defense and regulation of the Telmex monopoly.
§ 251(b)(2), added by the Telecommunications Act of 1996, requires all local exchange carriers (LECs) to offer number portability in accordance with the regulations of the Federal Communications Commission (FCC).
[29] LNP was first implemented in the US upon the establishment of the original Number Portability Administration Center (NPAC) in Chicago, Illinois, in 1998.
Thereafter, as switches and telephone networks were upgraded with location routing number (LRN) capability, LNP was deployed sequentially to the remaining Regional Bell Operating Company (RBOC) areas.
The Japanese Ministry of Internal Affairs and Communications (MIC) spent three years to put mobile number portability into practice, since its initial workgroup started in November, 2003.
In Albania, mobile number portability was implemented in 04.05.2011 (AKEP) Archived July 3, 2018, at the Wayback Machine.
For fixed-line numbers, it started on some geographical areas in September 2012 and was available in all country by 01.04.2013 (AKEP) Archived July 3, 2018, at the Wayback Machine.
The administrative solution for fixed and mobile number portability in Norway, the National Reference Database (NRDB), was put into service in 2000.
[48] The administrative Reference Entity (Entidade de Referencia (ER)) interconnecting all network operators and service providers is operated by a local third party, Portabil S.A. Archived March 21, 2009, at the Wayback Machine, a joint venture between the internationally well known companies Logica and Systor Trondheim AS.
In Spain, number portability among cell phone carriers is available since October 1, 2000, without any cost to the end user.
The technical details for the process are regulated by the CMT (Comisión del Mercado de las Telecomunicaciones or Telecoms Market Commission) and all carriers are obliged to comply with their requirements.
As of August 2007, cell number portability must complete in 5 business days (i.e. excluding weekends) from the moment the request is confirmed by the customer, with the actual switch occurring late at night to avoid missing any calls.
In the mature Spanish cell phone market (as of June 2007, with 107 lines per 100 inhabitants [49]), portability has been widely used by the competing carriers as a way to steal each other's customers, usually offering them free handsets or extra credit.
[51] Fixed line market is peculiar in Spain, since only two local loop providers can operate at each particular region (or demarcación as regulated by the CMT): a cable carrier (such as Ono, R and many others) and the former State monopoly (Telefónica).
As cable providers do not have a statewide footprint, many users have no actual chance of applying for "true" fixed number portability, that is, giving up Telefónica's service altogether.
In Serbia, number portability service on public telephone networks at a fixed location is available as of 1 April 2014.