CIRCULAR

Circular detailing conditions for number portability, procedures for number portability;

responsibilities of parties involved in number portability; technical process

to implement number portability 

Pursuant to the Law on Telecommunications dated 24/2023/QH15 November 24, 2023;

Pursuant to Decree No. 55/2025/NĐ-CP dated March 2, 2025 of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Science and Technology;

Pursuant to Decree No. 163/2024/NĐ-CP dated December 24, 2024 of the Government detailing certain provisions and implementing mechanisms of the Law on Telecommunications;

Pursuant to Decree No. 115/2025/NĐ-CP dated June 3, 2025 of the Government detailing certain provisions of the Law on Telecommunications regarding management of telecommunications numbers, Internet resources; compensation when the State recovers telecommunications numbers, Internet resources; auctioning rights to use telecommunications numbers, national domain name ".vn";

At the proposal of the Director of the Telecommunications Administration,

The Minister of Science and Technology issues this Circular detailing conditions for number portability, procedures for number portability; responsibilities of parties involved in number portability; technical process to implement number portability.

PART I

GENERAL PROVISIONS

Article 1. Scope of Regulation

This Circular details Clause 9, Article 12 of Decree No. 163/2024/NĐ-CP dated December 24, 2024 of the Government detailing certain provisions and measures to enforce the Law on Telecommunications regarding conditions for number portability; procedures for number portability; responsibilities of parties involved in number portability; technical process to implement number portability.

Article 2. Applicability

This Circular applies to enterprises licensed to provide mobile terrestrial telecommunications services and agencies, organizations, enterprises, individuals related to number portability.

Article 3. Explanation of Terms

In this Circular, the following terms are understood as follows:

1. Mobile subscriber is a telecommunications subscriber associated with the use of a mobile subscriber number H2H.

2. Subscriber registering for number portability service is a mobile subscriber who has completed all registration procedures for the number portability service as stipulated in Article 6 of this Circular but has not yet been provided with mobile terrestrial telecommunications services at the enterprise to which they are transferring.

3. Ported subscriber is a mobile subscriber who has registered for the number portability service and has been provided with mobile terrestrial telecommunications services at the enterprise to which they are transferring.

4. Departing enterprise is the enterprise providing mobile terrestrial telecommunications services to the subscriber registering for the number portability service until the time the service is cut off for that subscriber.

5. Receiving enterprise is the enterprise that will provide mobile terrestrial telecommunications services to the subscriber registering for the number portability service from the time the service is opened for that subscriber.

6. Original enterprise of the ported subscriber (original enterprise) is the enterprise providing mobile terrestrial telecommunications services allocated a block of numbers containing the number of the ported subscriber.

7. Porting schedule is a planned schedule regarding the time of service cutoff at the departing enterprise and service opening at the receiving enterprise for subscribers registering for the number portability service.

8. Database of ported subscribers is a collection of electronic data organized for access, exploitation, sharing, management, and updating through electronic means, including information related to all mobile subscribers who have used the number portability service stored at the Porting Center.

Article 4. General Provisions

1. The number portability service is provided based on a commercial contract between the receiving enterprise and the mobile subscriber.

2. The number portability service does not include the continued provision of telecommunications application services that the subscriber registering for the number portability service is using at the departing enterprise. The departing enterprise must ensure that no charges arise for any service from the time the service is cut off for the subscriber registering for the number portability service.

3. The fee paid for the number portability service to the receiving enterprise must be refunded if the subscriber fails to successfully port without violating the conditions for number portability.

4. Short message service application numbers 1441 are used to serve number portability transactions.

5. The mobile terrestrial information service provided to the subscriber registering for the number portability service follows the principle that the departing enterprise cuts off the service before the receiving enterprise opens it.

6. Enterprises providing mobile terrestrial telecommunications services and the Unit managing, operating, and exploiting the Porting Center reconcile discrepancies in the number of ported subscribers periodically each quarter to settle the fees for the use of transferred subscriber numbers according to the following:

a) The Unit managing, operating, and exploiting the Porting Center extracts data on the number of ported subscribers at the end of the quarter, excluding ported subscribers who won auctions.

b) For the first transfer of a subscriber number: the receiving enterprise bases the data on the number of ported subscribers at point a of this clause to pay the fee for the use of the subscriber number to the departing enterprise according to point d, Clause 4, Article 12 of Decree No. 163/2024/NĐ-CP.

c) For subsequent transfers of a subscriber number: the receiving enterprise bases the data on the number of ported subscribers at point a of this clause to pay the fee for the use of the subscriber number to the enterprise allocated the highest mobile subscriber number H2H usage fee currently being paid to the competent state authority.

7. Transferred subscriber numbers that are recovered according to the management regulations of the receiving enterprise will be returned to the original enterprise or the enterprise leasing numbers from the original enterprise according to the technical process in Diagram 7 of the attached Appendix to this Circular.

CHAPTER II

NETWORK PORTABILITY

Article 5. Conditions for Network Portability

1. The status condition of the mobile subscriber at the time of registering for network portability service: it must be a two-way active mobile subscriber on the network of the transferring enterprise.

2. Subscriber information condition: The subscriber information registered for network portability service at the receiving enterprise must match the information of that subscriber at the transferring enterprise, including the following basic information:

a) For individual subscriber information: the identification number and type of identification document used to register the mobile subscriber number H2H as prescribed in point a, b Clause 1 Article 17 Decree No. 163/2024/NĐ-CP.

b) For organizational subscriber information: the identification number and type of identification document proving legal entity according to civil law regulations or registration documents for establishing organizations according to legal provisions used to register mobile subscriber information H2H. In cases where an organization assigns an individual to use a SIM card, the individual's information must match the requirements stipulated in point a of this clause.

3. Service usage period condition:

a) For mobile subscriber numbers won through auction registering for network portability for the first time: the service usage period condition at the original enterprise shall be implemented according to the provisions of Clause 3 Article 45 Decree No. 115/2025/NĐ-CP.

b) For mobile subscriber numbers directly allocated registering for network portability for the first time: the minimum activation period of terrestrial mobile telecommunications services at the original enterprise must be at least 90 days before the date of registering for network portability service.

c) For mobile subscriber numbers registering for network portability from the second time onwards (including both auction-won numbers and directly allocated numbers): the minimum activation period of terrestrial mobile telecommunications services at the transferring enterprise must be at least 60 days before the date of registering for network portability service.

4. Conditions regarding charges for terrestrial mobile telecommunications services: postpaid subscribers must meet the following conditions simultaneously:

a) Have completed payment obligations for charges prior to the date of registering for network portability service.

b) Charges incurred during the current billing period at the time of registering for network portability service do not exceed VND 500,000 (five hundred thousand dong).

5. Conditions regarding international roaming service usage: postpaid subscribers must not have used international roaming services within 60 days prior to the date of registering for network portability service.

6. Other conditions:

a) Not violating behaviors prescribed in Article 9 of the Telecommunications Law or as required by competent state agencies.

b) There are no complaints or disputes regarding the use of the mobile subscriber number at the transferring enterprise.

c) Not currently undergoing another network portability transaction.

d) Not violating the telecommunications service provision and usage contract or general terms and conditions with the transferring enterprise. If the transferring enterprise refuses to allow the subscriber to transfer based on these provisions, the transferring enterprise must notify the subscriber registering for network portability service as prescribed in point a Clause 2 Article 7 Circular, and the receiving enterprise, and competent state agencies as prescribed in point a Clause 3 Article 11 Circular.

Article 6. Registration and Processing of Mobile Number Portability Services

1. Forms of registration for mobile number portability services

A mobile subscriber who wishes to register for mobile number portability services shall follow one of the following procedures:

a) Online through the use of an application provided by the transferring company. In cases where the software or application used for online registration cannot verify the information of the subscriber registering for mobile number portability services as stipulated in point a, Clause 4, Article 4 of this Law, the subscriber must register directly using one of the forms prescribed in points b and c of this clause.

b) Directly at a location owned and established by the transferring company (with a fixed address or mobile).

c) Directly at locations with a fixed address set up by another company, authorized by the transferring company to handle the registration of mobile number portability services.

2. Documents required for registration of mobile number portability services

When registering for mobile number portability services, organizations and individuals are responsible for presenting the original or certified copy of the original or electronic document having the same validity as the original or data message having the same validity as the original of the following documents:

a) For individuals who are Vietnamese citizens: Documents as prescribed in point a, Clause 1, Article 17 of Decree No. 163/2024/NĐ-CP.

b) For individuals who are foreign citizens: Documents as prescribed in point b, Clause 1, Article 17 of Decree No. 163/2024/NĐ-CP.

c) For organizations: Legal entity certification documents as prescribed by civil law or organization registration documents as prescribed by law (hereinafter referred to as organizational documents) and identity documents of the legal representative of the organization; List of individuals within the organization (legally confirmed by the organization) permitted to use telecommunications services under the contract model and general terms agreed upon between the organization and the transferring company (in cases where the organization assigns users); Documents as prescribed in points a and b of this clause for individuals listed. If the person registering for mobile number portability services is not the legal representative of the organization, they must present a valid power of attorney from the legal representative and their own identity documents as prescribed in points a and b of this clause which are still valid.

d) For organizations or individuals who have won mobile number portability auctions for H2H numbers: In addition to the documents prescribed in points a, b, and c of this clause, they must also present documents as prescribed by law on telecommunications number management to confirm the right to use the auctioned number.

đ) For persons under six years old or those who have not been issued identity documents as prescribed in point a of this clause, the registration for mobile number portability services of the subscriber must be carried out by their parents or guardians. For persons aged six or older but under fifteen who have been issued identity documents as prescribed in point a of this clause, they may register for mobile number portability services but must obtain written consent from their parents or guardians, including electronic or other verifiable formats. In addition to the documents presented as prescribed in point a of this clause, parents or guardians are responsible for presenting documents proving their relationship with the subscriber as prescribed by law.

3. Application for registration of mobile number portability services

Subscribers registering for mobile number portability services must fill in all required information on the Application for Registration of Mobile Number Portability Services. The Application for Registration of Mobile Number Portability Services (including both online and direct registration forms) is provided by the transferring company and includes at least the following contents:

a) For individuals registering for mobile number portability services: Information of the subscriber registering for mobile number portability services (including: full name, date of birth, nationality, contact phone number, address, identification number and type of identification as prescribed in Clause 2 of this Article); Mobile number being registered for portability; Name of the transferring company.

b) For organizations registering for mobile number portability services: Information of the organization and company registering for mobile number portability services (including: organization/company name, contact phone number, main office address, identification number and type of identification as prescribed in Clause 2 of this Article); Information on the identity document of the legal representative registering for mobile number portability services and information on the identity document of each individual within the organization corresponding to the mobile number assigned to that individual by the organization (as prescribed in point a of this clause); Mobile numbers being registered for portability; Name of the transferring company for each mobile number being registered for portability.

If the person registering for mobile number portability services is not the legal representative of the organization or company registering for mobile number portability services, they must provide information on the identity document of the authorized representative of the legal representative as prescribed in point a of this clause; Contact phone number of the authorized representative; valid power of attorney from the legal representative (number, date, month, year of the document).

c) Content confirming the subscriber's agreement to allow personal data processing in the Application for Registration of Mobile Number Portability Services to facilitate the mobile number portability service.

d) Information about the completion time of the mobile number portability service registration.

4. Verification of subscriber information for mobile number portability service registration

The transferring company shall verify the subscriber's information for mobile number portability service registration after receiving the documents (online or in person) from the subscriber registering for mobile number portability services as follows:

a) Verification for online service registration for number portability: Apply the video call solution to conduct the verification of subscriber identification information during the number portability service registration process, ensuring effectiveness equivalent to the face-to-face method; the video call solution must meet at least the following requirements: security and confidentiality; high resolution; continuous signal; real-time audio and visual interaction with the customer to ensure the recognition of a real person; display the image of the transaction staff and the customer registering for number portability service.

b) Verification for direct service registration for number portability: Compare and check the documents and information specified in Clauses 2 and 3 of this Article to match the individual or organization registering for the number portability service.

5. Confirmation and processing of number portability service registration requests.

After completing the number portability service registration as stipulated in Clauses 1, 2, 3, and 4 of this Article, the confirmation and verification of the number portability registration request shall be carried out as follows:

a) Within four hours from the completion time of the registration mentioned in Point d Clause 3 of this Article, the mobile subscriber who has registered for the number portability service sends a confirmation message (SMS) to the Number Porting Center using the format YCCM sent to number 1441, and the enterprise forwards the subscriber's number porting request message to the Number Porting Center.

b) If the Number Porting Center does not receive a valid confirmation message (SMS) from the subscriber and the number porting request message from the incoming enterprise within the aforementioned period, the number portability registration request will be canceled.

6. The Number Porting Center sends a message (SMS) to notify the subscriber who has registered for the number portability service about the acceptance and processing of their number porting request immediately after the subscriber sends a confirmation message (SMS) for the number portability service registration as prescribed in Point a Clause 5 of this Article.

7. Immediately upon receiving a valid confirmation message (SMS) from the subscriber and the number porting request message from the incoming enterprise, the Number Porting Center forwards the number porting request message to the outgoing enterprise for further processing.

8. The technical procedures for number portability registration and processing are implemented according to Flowchart 2 attached to this Circular.

Article 7. Refusal of Number Portability

1. The refusal to allow a subscriber to transfer their number may only be carried out in the following cases:

a) The subscriber registering for the number portability service does not meet one of the conditions specified in Circular No. 5.

b) The subscriber registering for the number portability service presents documents for registration that do not comply with Clause 2 of Article 6 of this Circular, or the documents presented for the number portability service registration are unclear, do not ensure clear and detailed digitalization of the documents, or contain inconsistent information after verification or cannot be verified.

c) At the request of a competent state agency.

2. Within four working hours from the time of receiving the number porting request from the Number Porting Center, the outgoing enterprise shall carry out:

a) Notify the subscriber who has registered for number porting via a message (SMS) when refusing number porting, the content of the message includes: reasons for refusal; evidence of refusal; guidance content for the subscriber to complete the number porting conditions as stipulated in Point c Clause 4 Article 12 Decree No. 163/2024/NĐ-CP.

b) Send a confirmation message of refusal to the Number Porting Center.

3. The technical procedures for refusing number porting are implemented according to Flowchart 2 attached to this Circular.

Article 8. Cancellation of Number Portability Service

1. From the time of registering for the number portability service until before receiving the schedule for number porting from the Number Porting Center, the subscriber who has registered for the number portability service may cancel the number porting through one of the following methods:

a) Sending an SMS to the Number Porting Center with the format HUYCM and sending it to number 1441.

b) Requesting the incoming operator to send a cancellation notice to the Number Porting Center. The incoming operator shall immediately process the request upon receipt of the subscriber's request. The incoming operator specifies the forms for accepting the subscriber's cancellation request (at the point of sale, telephone, SMS, etc.).

2. The Number Porting Center sends an SMS to the subscriber confirming the successful cancellation of the number porting request immediately after receiving a valid cancellation SMS from the subscriber or a cancellation notice from the incoming operator. Simultaneously, the Number Porting Center sends the cancellation notice to the outgoing operator and the incoming operator.

3. The outgoing operator and the incoming operator can only stop the number porting process upon receiving the cancellation request from the Number Porting Center.

4. The technical procedure for cancelling the number porting is carried out according to Diagram 3 attached as an appendix to this Circular.

Article 9. Implementation of Number Portability Service

1. After the subscriber completes the registration for the number portability service, the outgoing operator, the incoming operator, and the Unit managing, operating, and exploiting the Number Porting Center cooperate to implement the technical procedures according to Diagram 4 attached as an appendix to this Circular.

2. The call routing mechanism for calls and messages initiated from mobile subscribers to subscribers who have ported their numbers is applied under the "All Calls Query" (ACQ) method.

3. The call routing mechanism for calls and messages initiated from fixed-line subscribers of fixed telecommunications networks and private telecommunications networks serving Party and State agencies, defense, and security organizations to subscribers who have ported their numbers; from systems of equipment provided by organizations and enterprises offering telecommunications services and telecommunications application services to ported subscribers is applied under one of the following methods:

a) "All Calls Query."

b) "Onward Routing."

c) "Call Forward."

Chapter III

RIGHTS AND RESPONSIBILITIES OF THE PARTIES INVOLVED

Article 10. Rights and Responsibilities of Subscribers Registering for the Number Portability Service

1. Subscribers registering for the number portability service have the following rights:

a) To be provided with the number portability service on an equal basis without discrimination among mobile subscribers when they meet the conditions for number porting as stipulated in Article 5 of this Circular.

b) To be provided by the outgoing operator with forms to check the porting conditions, tools for subscribers to self-check their porting capabilities, and information as prescribed in point c, Clause 4, Article 12 of Decree No. 163/2024/NĐ-CP in cases where the subscriber does not meet the porting conditions.

c) To request the outgoing operator, the incoming operator, and the Unit managing, operating, and exploiting the Number Porting Center to resolve complaints, inquiries, and suggestions regarding the number porting service and provide reasons and evidence for refusing the porting.

d) To request the outgoing operator to complete all related obligations and commitments with the outgoing operator.

2. Subscribers registering for the number portability service have the following responsibilities:

a) To provide full documentation and materials as prescribed in Clause 2, Article 6 of this Circular and fill in all required information on the Application Form for the Number Portability Service as prescribed in Clause 3, Article 6 of this Circular.

b) To ensure completion of all related obligations and commitments and terminate the contract with the outgoing operator within a maximum period of 60 days from the date of successful porting. Beyond this period, the subscriber number will be returned to the outgoing operator according to the technical procedure at Diagram 6 in the Appendix attached to this Circular.

c) To pay the charges for the number portability service to the incoming operator when registering for the number portability service.

d) To familiarize themselves with their rights and responsibilities in using the number portability service.

đ) To allow the outgoing operator, the incoming operator, and the Unit managing, operating, and exploiting the Number Porting Center to use the registration information for the number portability service to provide the service for them.

Article 11. Responsibilities of enterprises providing terrestrial mobile telecommunications services

In addition to the responsibilities prescribed in Article 12 of Decree No. 163/2024/NĐ-CP, enterprises providing terrestrial mobile telecommunications services also have the following responsibilities:

1. Responsibilities of enterprises providing terrestrial mobile telecommunications services:

a) Coordinate with the Management, Operation, and Exploitation Unit of the Number Portability Center and other enterprises providing terrestrial mobile telecommunications services to establish and provide services in accordance with the Interoperability Process for Number Portability Implementation.

b) Ensure that the number portability service provision system at the enterprise and the transmission link connecting to the Number Portability Center operate stably and smoothly to implement number portability.

c) Update information from the Subscriber Database for number portability to maintain the provision of telecommunications services and telecommunications application services.

d) Coordinate with agencies and organizations managing private telecommunications networks serving Party and State agencies, defense, security, and enterprises providing telecommunications services and telecommunications application services to develop technical plans, connections, and routing according to Clause 3, Article 9 of this Circular on the basis of ensuring the interests of all parties.

đ) Ensure telecommunications infrastructure to meet the connection needs of agencies and organizations managing, operating, and exploiting private telecommunications networks serving Party and State agencies, defense, and security.

e) Publicly publish on the enterprise's application and website a list of mobile telecommunications service packages applying limited transfer rights clauses for mobile subscribers, while sending this information to the Management, Operation, and Exploitation Unit of the Number Portability Center for announcement.

g) Ensure physical facilities and equipment systems to receive and authenticate online and direct registration requests for number portability services from mobile subscribers as stipulated in Article 6 of this Circular.

h) Conduct reconciliation and settle centralized transaction processing costs with the Management, Operation, and Exploitation Unit of the Number Portability Center.

i) Conduct reconciliation and settle usage fees for transferred subscriber numbers according to Clause 6, Article 4 of this Circular.

2. Responsibilities of the receiving enterprise:

a) Charge the service fee for number portability from subscribers registering for number portability services.

b) Only provide terrestrial mobile telecommunications services to subscribers registering for number portability services after completing the review, inspection, and ensuring that their subscriber information has been compared, updated, verified, stored, and managed in compliance with current regulations.

3. Responsibilities of the transferring enterprise:

a) Provide complete information and evidence for refusing number portability to the receiving enterprise and competent state authorities when requested or during reconciliation.

b) Fulfill all related obligations and commitments and terminate contracts with transferring subscribers after the completion of the number portability process and during post-portability monitoring according to Flowchart 5 attached to this Circular.

c) Permanently delete data about transferred subscribers' information after the retention period for subscriber information as prescribed by law has expired.

d) Take the lead and coordinate with the receiving enterprise, the Management, Operation, and Exploitation Unit of the Number Portability Center, and relevant parties to address customer complaints, inquiries, and suggestions related to number portability services.

Article 12. Responsibilities of the Unit Managing, Operating, and Exploiting the Number Portability Center

In addition to the responsibilities stipulated in Article 12 of Decree No. 163/2024/NĐ-CP, the Unit Managing, Operating, and Exploiting the Number Portability Center also has the following responsibilities:

1. To take the lead and coordinate with terrestrial mobile telecommunications service providers to develop and issue the Coordination Procedures for Implementing Number Portability.

2. To manage, operate, and exploit the Number Portability Center, ensuring its stable and uninterrupted operation; ensuring that the telecommunications infrastructure of the Number Portability Center is available for organizations and enterprises to connect to.

3. To guide terrestrial mobile telecommunications service providers to establish transmission lines and connections to the Number Portability Center to provide number portability services in accordance with the provisions of this Circular.

4. To take the lead and coordinate with relevant parties to determine the costs of processing centralized number portability transactions as prescribed in Clause 5, Article 12 of Decree No. 163/2024/NĐ-CP.

5. To receive complaints, inquiries, and suggestions from the public regarding number portability through online forms on the Telecommunications Administration's website, hotline telephone (hotline), and other forms (if any).

Article 13. Responsibilities of Organizations and Enterprises Providing Telecommunications Services and Telecommunications Application Services

1. To coordinate with the Unit Managing, Operating, and Exploiting the Number Portability Center or negotiate with mobile telecommunications enterprises to develop technical plans and select routing mechanisms as prescribed in Clause 3, Article 9 of this Circular to ensure the stable and uninterrupted provision of telecommunications services and telecommunications application services to number portability subscribers.

2. Organizations and enterprises applying the "Full Query" routing mechanism must ensure the following contents:

a) To update subscriber information from the Subscriber Database to maintain the provision of telecommunications services and telecommunications application services and not to provide the Subscriber Database to third parties in any form.

b) Data related to number portability subscribers may only be used for the purpose of providing telecommunications services and telecommunications application services.

3. Enterprises providing local and long-distance domestic and international telephone services must ensure that their telecommunications infrastructure meets the connection requirements of agencies and organizations managing, operating, and exploiting dedicated telecommunications networks serving Party, State, defense, and security agencies.

4. To coordinate with relevant parties to resolve customer complaints, inquiries, and suggestions related to number portability services.

PART IV

IMPLEMENTATION

Article 14. Implementation Organization

1. The Head of the Office, the Director of the Telecommunications Administration, the Heads of agencies and units under the Ministry; the Unit Managing, Operating, and Exploiting the Number Portability Center; terrestrial mobile telecommunications service providers; telecommunications service providers and telecommunications application service providers and related organizations and individuals are responsible for implementing this Circular.

2. During implementation, if any issues arise, relevant agencies, organizations, and individuals should promptly report them to the Ministry of Science and Technology (Telecommunications Administration) for review and resolution.

Article 15. Implementation Provisions

1. This Circular takes effect from August 10, 2025.

2. Circular No. 35/2017/TT-BTTTT dated November 23, 2017 of the Minister of Information and Communications on the provision of terrestrial mobile number portability services remains valid until the date this Circular takes effect./.

1. General number portability flowchart

 

a. Flowchart (2) - Initiate number portability

This process performs the following tasks:

- The subscriber registers for number portability services with the incoming service provider and confirms the request via SMS with the syntax YCCM sent to 1441;

- The incoming service provider processes the confirmation of the request and initiates a number portability request message from the subscriber to the Number Portability Center;

- The outgoing service provider checks the fulfillment of number portability service usage terms and sends an Accept or Reject message to the Number Portability Center for the subscriber. If the outgoing service provider rejects the subscriber's portability request, the outgoing service provider will send a notification via SMS to the subscriber who registered for portability.

b. Flowchart (3) - Cancel number portability

Before receiving the Porting Schedule, a subscriber who has registered for number portability services and wishes to cancel their registration can request cancellation according to Clause 1, Article 8 of this Circular. The subscriber's porting request will be halted from the moment they receive an SMS notification confirming successful cancellation of the request.

c. Flowchart (4) - Activate number portability

A subscriber who has been approved for number portability and has not canceled their request will be:

- Notified of the porting schedule by the Number Portability Center;

- At the time of porting processing, the outgoing service provider will terminate services, followed by the incoming service provider activating services for the subscriber;

- Post-porting routing information for the subscriber will be updated and notified to relevant service providers to facilitate routing of telecommunications and telecommunications application services to the ported subscriber.

d. Flowchart (5) - Post-porting control

Subscribers who have not fulfilled certain obligations or commitments with the outgoing service provider will be included in the post-porting control flowchart. Post-porting control involves reviewing the fulfillment of obligations and commitments by the ported subscriber to the outgoing service provider.

đ. Flowchart (6) – Return the number back to the outgoing service provider

A mobile subscriber who transfers networks but fails to fulfill obligations and commitments with the transferring enterprise after the network transfer shall be processed to return the mobile number to the transferring enterprise.

e. Flowchart (7) - Returning the mobile number to the original enterprise

The mobile number of a transferred mobile subscriber that is reclaimed according to regulations on managing and using telecommunications number pools or regulations on the use of telecommunications services by the receiving enterprise must be returned to the original enterprise.

2. Network transfer initiation flowchart

- Step (1): The mobile subscriber, group of mobile subscribers (referred to as Subscriber) registers for the network transfer service at the receiving enterprise in accordance with Article 6 of this Circular.

- Step (2): The receiving enterprise will accept the network transfer request of the Subscriber through procedures for registering the network transfer service. After receiving the documents (online or in person) of the Subscriber registering for the network transfer service, the receiving enterprise will verify the information of the registered mobile subscriber in accordance with Clause 4, Article 6 of this Circular.

- Step (3): The Subscriber and the receiving enterprise will confirm and process the registration request for the network transfer service in accordance with Clause 5, Article 6 of this Circular.

- Step (4): During the confirmation and processing period of the network transfer service registration request (maximum 04 hours), the Network Transfer Center will check whether the Subscriber receives a valid confirmation message (SMS) and the request message for network transfer from the receiving enterprise according to the technical parameters agreed upon in the coordinated implementation process of network transfer.

- Step (5): Immediately after receiving a valid confirmation message (SMS) from the Subscriber and a valid request message for network transfer from the receiving enterprise, the Network Transfer Center sends the request message for network transfer to the transferring enterprise for further processing.

- Step (6): The transferring enterprise accepts the request message for network transfer received from the Network Transfer Center. The transferring enterprise has a maximum of 04 working hours to perform checks on the content of the information according to the terms of use of the network transfer service of the Subscriber on the MNP system and related management systems. After completing the checks, the transferring enterprise sends the results of the checks to the Network Transfer Center from its MNP system, confirming either Acceptance or Rejection for the Subscriber to proceed with the network transfer.

In case the transferring enterprise rejects the Subscriber's network transfer, the transferring enterprise sends a notification by message (SMS) to the Subscriber including: reasons for rejection; evidence of rejection; guidance content for the Subscriber to complete the conditions for network transfer in accordance with Point c, Clause 4, Article 12 of Decree No. 163/2024/NĐ-CP.

- Step (7): The Network Transfer Center immediately forwards the results of the checks according to the terms of use of the network transfer service of the Subscriber received from the transferring enterprise to the receiving enterprise. At the same time, the Network Transfer Center sends a message (SMS) with the results of the checks according to the terms of use of the network transfer service to the Subscriber who has registered for the network transfer service.

- Step (8): The receiving enterprise accepts the results of the checks on the terms of use of the network transfer service of the Subscriber on its MNP system. The Subscriber receives a message (SMS) with the results of the checks according to the terms of use of the network transfer service.

3. Network transfer cancellation flowchart

- Step (1): The Subscriber registers to cancel their network transfer request by sending a request to the channels specified by the receiving enterprise or sending a message (SMS) to the Network Transfer Center.

- Step (2.1): The receiving enterprise accepts the Subscriber's network transfer cancellation request through the reception methods it specifies.

- Step (2.2): The Network Transfer Center accepts the network transfer cancellation request by receiving a message (SMS) from the Subscriber. Then it proceeds to Step (4) - syntax checking of the message.

- Step (3): After accepting the request from the Subscriber, the receiving enterprise initiates a cancellation request message on its MNP system and then sends the request to the Network Transfer Center.

- Step (4): The Network Transfer Center performs a format check of the cancellation request message from the receiving enterprise according to the specified technical parameters (Correct/Incorrect); or performs a syntax check of the Subscriber's cancellation request message; or checks the timing of receiving a valid cancellation request message (From the time of registering the network transfer service until before receiving the network transfer schedule notification from the Network Transfer Center).

If the format check or syntax check is Correct, proceed to Step (5);

If the format check or syntax check is Incorrect, the Network Transfer Center will send an error notification to the receiving enterprise. The receiving enterprise must resend the cancellation request message to the Network Transfer Center.

- Step (5): The Network Transfer Center stops further processing of the Subscriber's network transfer request according to the prescribed network transfer process. Subsequently, all requests related to the network transfer transaction of the Subscriber who requested cancellation will not be processed. The Network Transfer Center will then notify the successful cancellation of the network transfer to the receiving enterprise, the transferring enterprise, and send a message (SMS) to the Subscriber about the successful cancellation of the network transfer request.

- Step (6): The receiving enterprise, the transferring enterprise, and the Subscriber receive the successful network transfer cancellation notification from the Network Transfer Center.

4. Network transfer activation flowchart

- Step (1): The mobile subscriber is decided by the transferring enterprise to agree to the network transfer, the Network Transfer Center schedules the network transfer for the Subscriber. After scheduling, the Network Transfer Center notifies the network transfer schedule to the transferring enterprise, the receiving enterprise, and the Subscriber.

- Step (2): Before the scheduled time for processing the network transfer for the Subscriber, the receiving enterprise and the transferring enterprise have the responsibility to send readiness notifications for processing the network transfer according to the schedule to the Network Transfer Center.

- Step (3): Based on the network switching schedule and the processing time frame for service cut-off from 09:00 to 16:00 on working days, the transferring enterprise has a maximum of one working hour for postpaid subscribers and fifteen minutes for prepaid subscribers to process the service cut-off for the Subscriber on their terrestrial mobile communication network system. After completing the processing, the transferring enterprise sends a notification of completed service cut-off processing to the Subscriber to the Switching Center.

- Step (4): The Switching Center receives the notification of completed service cut-off processing from the transferring enterprise and immediately forwards this notification to the receiving enterprise.

- Step (5): The receiving enterprise receives the notification of completed service cut-off processing from the Switching Center. The receiving enterprise has a maximum of one working hour for postpaid subscribers and fifteen minutes for prepaid subscribers to process the service activation for the Subscriber on their terrestrial mobile communication network system. After completing the processing, the receiving enterprise is responsible for sending a notification of completed service activation processing to the Subscriber to the Switching Center.

- Step (6): The Switching Center receives the notification of completed service activation processing from the receiving enterprise and immediately broadcasts a promotional notice of completed network switching processing to the Subscriber to all parties connected to the Switching Center and updates the Subscriber's information in the switching database.

- Step (7): All participating parties must update their respective roaming query databases within a maximum of fifteen minutes to send a confirmation notice of receipt of the promotional notice to the Switching Center during the specified period, ensuring the routing of telecommunications services.

5. Post-Switching Control Flowchart

- Step (1): The Subscriber has a maximum of sixty days after successful switching to complete related obligations and terminate the contract with the transferring enterprise (these are commitments made by the Subscriber when registering for the switching service).

After this period, the transferring enterprises review their relevant management systems and determine the completion status of the obligations and commitments of the switched Subscribers as stipulated in Point b Clause 2 Article 10 of this Circular. They then initiate Post-Switching Control Requests for Subscribers who have not fulfilled their obligations and commitments and notify the completion of post-switching control for those who have fulfilled their obligations and commitments. These notifications are then sent to the Switching Center.

Prior to the expiration of the post-switching control completion deadline for Subscribers after successful switching:

• The transferring enterprise may send a notification of completed post-switching control for Subscribers who have fulfilled their obligations and commitments to the Switching Center.
• The Switching Center will not process Post-Switching Control Requests for Subscribers who have not fulfilled their obligations and commitments during this period.

- Step (2): The Switching Center receives the Post-Switching Control notifications from the transferring enterprise and checks the format of these notifications according to the technical specifications (Correct/Incorrect).

- Step (3): In the case where the format of the notifications is Correct, the Switching Center forwards the Post-Switching Control notifications to the receiving enterprise.

For Subscribers who have completed post-switching control, the Switching Center updates its MNP system;

- Step (4): In the case where the format of the notification is Incorrect, the Switching Center does not forward the Post-Switching Control notifications from the transferring enterprise and sends an error notification to the transferring enterprise. The transferring enterprise must resend the correctly formatted Post-Switching Control notifications to the Switching Center.

- Step (5): The receiving enterprise receives the Post-Switching Control notifications from the Switching Center.

• For Subscribers who have completed post-switching control, the receiving enterprise updates its MNP system;
• For Subscribers who have not completed post-switching control, the receiving enterprise verifies again with the Subscriber regarding the completion status of their obligations and commitments to the transferring enterprise. If the Subscriber has fulfilled their obligations and commitments within the prescribed timeframe but the transferring enterprise has not updated its relevant management systems, the receiving enterprise collects verification evidence from the Subscriber. The receiving enterprise then sends this evidence of the Subscriber's fulfillment of obligations and commitments to the transferring enterprise to the Switching Center.

- Step (6): The Switching Center receives the evidence of the Subscriber's fulfillment of obligations and commitments from the receiving enterprise and forwards this evidence to the transferring enterprise.

- Step (7): The transferring enterprise receives the evidence of the Subscriber's fulfillment of post-switching commitments from the Switching Center and verifies the accuracy of this evidence.

• If the evidence is correct, the transferring enterprise updates its relevant management systems and resends a notification of completed post-switching control for Subscribers who have fulfilled their obligations and commitments to the Switching Center for updating.
• If the evidence is incorrect, proceed to Step (9).

- Step (8): For Subscribers who have truly not fulfilled their commitments with the transferring enterprise after successful switching and have no verification evidence, they will be returned to the transferring enterprise.

- Step (9): The transferring enterprise and the Subscriber jointly process and resolve evidence of completed obligations and commitments that were not fulfilled as provided by the Subscriber to the receiving enterprise outside the MNP process. After reaching an agreement on processing, the transferring enterprise continues the post-porting control process to update the status of post-porting control.

6. Flowchart for returning subscriptions to the transferring enterprise

- Step (1): Subscriptions that have not completed their obligations and commitments with the transferring enterprise within a maximum period of 60 days will be returned to the transferring enterprise.

The transferring enterprise compiles subscriptions that have not completed their commitments when registering for number portability services on its related management systems.

- Step (2): Thereafter, the transferring enterprise initiates a request for returning subscriptions to the transferring enterprise (subscription return request notice) on its MNP system and sends this request to the Number Portability Center.

- Step (3): The Number Portability Center receives the subscription return request notice from the transferring enterprise and checks the format of the notice according to the technical specifications defined.

In case the format of the notice is Correct, the Number Portability Center forwards the subscription return request notice to the receiving enterprise.

In case the format of the notice is Incorrect, the Number Portability Center does not forward the subscription return request notice of the transferring enterprise and sends an error notification to the transferring enterprise. The transferring enterprise must resend a new subscription return request notice to the Number Portability Center.

- Step (4): The receiving enterprise receives the subscription return request notice and checks the subscription return request on its related management systems. It then sends a reply notice of Acceptance or Rejection of the subscription return request back to the transferring enterprise.

- Step (5): The Number Portability Center receives the reply notice of the subscription return request from the receiving enterprise and checks the format of the notice according to the technical specifications defined (Correct/Incorrect).

In case the format of the notice is Correct, the Number Portability Center forwards the reply notice of the receiving enterprise to the transferring enterprise.

In case the format of the notice is Incorrect, the Number Portability Center does not forward the reply notice of the receiving enterprise and sends an error notification to the receiving enterprise. The receiving enterprise must resend a new reply notice of the subscription return request to the Number Portability Center.

- Step (6): The transferring enterprise receives the reply notice of the subscription return request from the Number Portability Center.

For subscription return requests accepted by the receiving enterprise, the transferring enterprise prepares its MNP system to handle the subscription return porting.

For subscription return requests rejected by the receiving enterprise, the transferring enterprise reviews, exchanges, and reaches an agreement on handling with the receiving enterprise and the Number Portability Center (if necessary).

- Step (7): The Number Portability Center, the transferring enterprise, and the receiving enterprise implement the subscription return process according to the Activation Flowchart: porting from the receiving enterprise back to the transferring enterprise. After completing the subscription return porting, telecommunications enterprises and relevant parties update the query database within the specified time frame to ensure routing of telecommunications services.

7. Flowchart for returning numbers to the original enterprise

- Step (1): The receiving enterprise periodically checks its related management systems and identifies mobile numbers of subscribers who violated regulations leading to the need for number recovery. For subscribers whose numbers are recovered, the receiving enterprise initiates a request for returning numbers to the original enterprise on its MNP system and sends the request to the Number Portability Center.

- Step (2): The Number Portability Center receives the number return request from the receiving enterprise and checks the format of the request according to the technical specifications defined (Correct/Incorrect).

- Step (3): In case the format of the notice is Correct, the Number Portability Center broadcasts a notice announcing the return of numbers to the original enterprise to all connected parties and updates the information in the porting database.

- Step (4): In case the format of the notice is Incorrect, the Number Portability Center does not process the number return request of the receiving enterprise and sends an error notification to the receiving enterprise. The receiving enterprise must resend a new number return request to the Number Portability Center.

- Step (5): All other related parties are responsible for updating their corresponding query databases and sending confirmation of receipt of the broadcast notice announcing the return of numbers to the original enterprise to the Number Portability Center within a maximum of 15 minutes.