- Created by Oleg Shevtsov, last modified by Oleksandr Zaluhovskyi on 2026-05-11
Ticket Number | |
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Project goal | Add native support of multi-IMSI SIM cards to PortaBilling |
Why this project exists ? | At the moment, PortaBilling doesn't have a native multi-IMSI support and only workarounds are possible |
Who are the users / whom we bring value ? | CSP |
What are the benefits for CSP / PortaSwitch owner? | Optimised roaming costs and reduced operational expenditure (OPEX) on manual provisioning tasks. Moreover, the CSP owner may avoid unnecessary negotiations and interconnect with every MNO abroad to get immediate worldwide coverage of their SIM product. |
Target Build | N/A |
Area | BillingAdmin, BillingEngine, ESPF |
Additional Info
Typical case: MVNO offering 2 identities - one for home country, another one to decrease roaming costs. Dual-IMSI card.
In the home country, applet on the SIM card detects that home operators are available, thus uses home IMSI. In roaming, applet on SIM detects that roaming IMSI has to be activated.
Specifications
References
[feasibility check] Associate vendor with Gy/Ro AAA based on provided network identifiers: BE-5174
Definitions, acronyms and abbreviation
Abbreviation | Description |
|---|---|
CSP | Communication Service Provider |
MNO | Mobile Network Operator. A company that owns and operates mobile network infrastructure (radio access, core network, spectrum). |
MVNO | Mobile Virtual Network Operator. A mobile service provider that does not own radio infrastructure and instead uses an MNO’s network. Focuses on branding, pricing, and customer experience. |
OPEX | Operational Expenditure. Ongoing operational costs required to run a business, such as: network operations, customer support, platform licensing. Lower OPEX improves profitability and scalability. |
SIM Card | Synonym of the universal integrated circuit card (UICC). The smart card used in mobile terminals in GSM and UMTS networks. The UICC ensures the integrity and security of all kinds of personal data. |
eSIM | Embedded SIM. A digital SIM built into the device that can be remotely provisioned without a physical card. Enables instant activation, profile switching, and global connectivity. |
SM-DP+ | Subscription Manager – Data Preparation Plus. A backend system that: securely prepares and stores eSIM profiles & delivers them to devices over the air. It is a core component of the eSIM ecosystem. |
OTA | Over-The-Air. Wireless, remote transmission of data - specifically, network carrier profiles and operating system updates—directly to a device's embedded Secure Element (eUICC). Unlike traditional SIM cards that require physical installation, OTA allows eSIMs to be managed, activated, and switched remotely without any physical contact with the device. |
IMSI | An international mobile subscriber identity. A unique number, usually fifteen digits, associated with Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) network mobile phone users. The IMSI is a unique number identifying a mobile subscriber. In the past IMSI was written on a SIM card during manufacturing process. Now there are possibilities of OTA updates, when IMSI and authentication parameters are provisioned over the air - for example eSIM or proprietary services by Gemalto. |
MCC and MNC | Mobile Country Code and Mobile Network Code are critical identifiers that allow a mobile device to connect to a foreign network while ensuring the subscriber is correctly identified, billed, and allowed access to services. Together, they form the PLMN (Public Land Mobile Network) ID or HNI (Home Network Identity), which acts as a "fingerprint" for a mobile operator. |
ICCID | Integrated Circuit Card Identifier. A unique serial number that identifies a SIM or eSIM. |
MSISDN | Mobile Station International Subscriber Directory Number. The phone number assigned to a subscriber. This is the public number people dial to reach a user. |
| HSS | Home Subscriber Server. Stores subscriber identity, authentication data, and service permissions. |
| PCRF | Policy and Charging Rules Function. Defines policy and charging rules for data usage and service access. Together with HSS, they control who the subscriber is and what they’re allowed to do. |
| Diameter | A signaling protocol used in mobile core networks. It enables authentication, authorization, policy control, and charging between network elements. |
3GPP | 3rd Generation Partnership Project. The global standards body that defines mobile network technologies (3G, 4G, 5G). Ensures interoperability across vendors and operators worldwide. |
| S6a | A Diameter interface between: MME (core network) and HSS. Used for subscriber authentication, location updates, and mobility management in LTE networks. |
Gy | A real-time charging interface between the network and the Online Charging System (OCS). Used for prepaid balance control during active sessions. |
Ro | A Diameter interface used for online charging across different service types. Often used for roaming and converged charging scenarios. |
sFTP | Secure File Transfer Protocol. A secure method for transferring files between systems. Commonly used for: CDR exchange, reports, batch provisioning files |
AVPs | Attribute-Value Pairs. The basic data units inside Diameter messages. |
Ki and OPc | Cryptographic keys stored on the SIM/eSIM and in the network which ensure secure network access and protection against fraud:
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