Porting Process (Number Portability Process)

Description

The porting process is defined in 3GPP TS 21.905 and TS 22.066 as a description of the transfer of a number between network operators. This process is the operational embodiment of Mobile Number Portability (MNP), enabling a subscriber to retain their MSISDN when changing from a donor operator to a recipient operator. The porting process involves a series of coordinated steps that span administrative procedures, database updates, and network reconfiguration, ensuring that calls and messages are correctly routed to the subscriber after the port is complete.

The porting process begins when a subscriber requests to port their number to a new operator. The recipient operator validates the request, checks for any contractual obligations with the donor operator, and initiates a porting request. The donor operator is then notified and must either accept or reject the request based on regulatory rules. Once accepted, a scheduled porting time is agreed upon. During this time, the recipient operator provisions the subscriber's data in its network elements, such as the HLR/HSS, and the donor operator prepares to deactivate the subscription.

On a technical level, the porting process requires updates to routing databases. In many implementations, a Number Portability Database (NPDB) or Central Reference Database is used. When a call is made to a ported number, the originating network queries the NPDB to determine the recipient network. The call is then routed to the recipient network's gateway. In IMS and VoLTE environments, ENUM and SIP signaling are used to resolve the ported number to the correct serving entity. The porting process also involves updating interconnect agreements and billing systems to reflect the new routing.

The porting process is subject to regulatory oversight. Regulators typically mandate maximum porting times (e.g., a few working days) and define the rights and obligations of both subscribers and operators. They may also specify the technical standards to be used, such as the use of specific signaling protocols or database architectures. The 3GPP specifications provide a common framework for these processes, ensuring interoperability across different networks and countries.

In summary, the porting process is a multi-faceted procedure that combines administrative, technical, and regulatory elements. It is essential for the functioning of number portability and requires close coordination between operators, regulators, and vendors. The 3GPP definition in TS 21.905 and TS 22.066 provides a standardized description that facilitates communication and implementation.

Purpose & Motivation

The porting process exists to operationalize number portability, allowing subscribers to transfer their telephone number from one network operator to another. Before the introduction of number portability, subscribers who wished to change operators had to abandon their existing number and adopt a new one. This created a significant barrier to competition, as subscribers were reluctant to change numbers due to the inconvenience and potential loss of contacts. The porting process was developed to remove this barrier by providing a standardized, regulated procedure for transferring numbers between operators.

The process addresses several technical and administrative challenges. Technically, it ensures that calls and messages are correctly routed to the subscriber after the port, which requires updates to databases and signaling systems. Administratively, it defines the steps that operators must follow, including validation of the porting request, coordination of the porting time, and deactivation of the old subscription. Regulatorily, it provides a framework for oversight, ensuring that operators comply with mandated porting times and do not unreasonably delay or reject porting requests.

The 3GPP specifications 21.905 and 22.066 define the porting process as a description of the transfer of a number between network operators. This definition, while concise, encompasses the complex interplay of technical, administrative, and regulatory elements. The porting process has evolved over time to accommodate new technologies such as IMS, VoLTE, and 5G, but its fundamental purpose remains the same: to enable seamless number portability and promote competition in the telecommunications market.