What are the benefits and challenges of using IMSI and MSISDN over other identifiers in mobile communication?

1 IMSI: The Unique Subscriber Identifier

IMSI is a 15-digit number that is stored in the SIM card and assigned by the network operator. It consists of three parts: the Mobile Country Code (MCC), the Mobile Network Code (MNC), and the Mobile Subscriber Identification Number (MSIN). IMSI is used to register the subscriber to the network, to establish a secure connection, and to provide roaming services. IMSI is a unique and permanent identifier that cannot be changed by the user. The main benefit of using IMSI is that it enables the network to recognize the subscriber regardless of the device or location. The main challenge of using IMSI is that it can be intercepted and tracked by unauthorized parties, compromising the privacy and security of the subscriber.

2 MSISDN: The Public Phone Number

MSISDN is a 15-digit number that is assigned by the network operator and linked to the IMSI. It consists of three parts: the Country Code (CC), the National Destination Code (NDC), and the Subscriber Number (SN). MSISDN is used to make and receive calls and messages, to access value-added services, and to bill the subscriber. MSISDN is a public and changeable identifier that can be transferred to another device or SIM card. The main benefit of using MSISDN is that it allows the subscriber to communicate with other parties using a familiar and convenient format. The main challenge of using MSISDN is that it can be spoofed or hijacked by malicious actors, resulting in fraud or identity theft.

3 Other Identifiers: The Alternatives and Complements

IMSI and MSISDN are not the only identifiers used in mobile communication. The International Mobile Equipment Identity (IMEI) is a 15-digit number stored in the device and assigned by the manufacturer, used to prevent theft, block stolen devices, and support device management. The Temporary Mobile Subscriber Identity (TMSI) is a random number assigned by the network and linked to the IMSI, used to protect the IMSI from eavesdropping and tracking. The Mobile Station Roaming Number (MSRN) is a temporary number assigned by the visited network and linked to the MSISDN, used to route calls and messages to the roaming subscriber. These identifiers can work together with IMSI and MSISDN to provide more efficient, secure, and flexible mobile communication; however, they can also bring additional complexity, cost, and compatibility issues.

4 IMSI and MSISDN: The Future Trends

IMSI and MSISDN are still widely used in mobile communication, but they are also facing some changes in the evolving market and technology. IP Multimedia Subsystem (IMS) is a framework that integrates voice, data, and multimedia services over IP networks, using a new identifier called IMPU. Embedded SIM (eSIM) eliminates the need to physically swap SIM cards and enables the subscriber to switch between multiple operators and plans. Rich Communication Services (RCS) is a set of standards that enhances SMS and MMS services with features such as group chat, video call, file transfer, and location sharing. It uses a new identifier called RCS ID. All of these trends offer new opportunities and challenges for using IMSI and MSISDN in mobile communication, requiring more coordination, innovation, and regulation among the stakeholders.

5 Here’s what else to consider

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