MSIN (Mobile Subscription Identification Number)

Last updated on May 10, 2023

Mobile Subscription Identification Number (MSIN) is a unique number assigned to a mobile subscriber as part of their subscriber identity module (SIM). This number is used to identify and authenticate the subscriber to the mobile network operator (MNO) and enables the MNO to provide various services to the subscriber, including voice calls, messaging, and data services.

In this article, we will discuss in detail the Mobile Subscription Identification Number, how it is generated, and its significance in the mobile telecommunications network.

Overview of Mobile Subscription Identification Number (MSIN)

The Mobile Subscription Identification Number (MSIN) is a unique identifier that is assigned to a mobile subscriber. This number is used to identify the subscriber to the mobile network operator (MNO) and is part of the International Mobile Subscriber Identity (IMSI).

The IMSI is composed of three parts, including the Mobile Country Code (MCC), Mobile Network Code (MNC), and the MSIN. The MCC is a three-digit code that identifies the country in which the subscriber is located, while the MNC is a two or three-digit code that identifies the MNO. The MSIN is a variable-length number that identifies the individual subscriber within the MNO's network.

The MSIN is stored in the subscriber identity module (SIM), which is a small card that is inserted into the mobile device. The SIM contains various information, including the IMSI, which is used to authenticate the subscriber to the network. When the subscriber powers on their mobile device, the device sends a signal to the nearest base station, which in turn sends a signal to the MNO's core network. The core network then authenticates the subscriber based on their IMSI and allows them access to the network.

How is MSIN generated?

The Mobile Subscription Identification Number (MSIN) is generated by the MNO and is unique to each subscriber. When a subscriber purchases a SIM card, the MNO assigns an MSIN to that SIM card. The MSIN is generated using a combination of the MNO's network code and a unique number that is assigned to the subscriber.

The unique number that is assigned to the subscriber is typically a sequential number that is generated by the MNO's provisioning system. This number is then combined with the MNO's network code to create the MSIN. The length of the MSIN can vary depending on the MNO's network architecture and the number of subscribers on the network.

For example, if the MNO's network code is 123 and the subscriber's unique number is 456789, then the MSIN for that subscriber would be 123456789. If the MNO's network code is 456 and the subscriber's unique number is 123456789, then the MSIN for that subscriber would be 456123456789.

Significance of MSIN in the Mobile Telecommunications Network

The Mobile Subscription Identification Number (MSIN) is a crucial component of the mobile telecommunications network. It is used to identify and authenticate the subscriber to the network, which enables the MNO to provide various services to the subscriber.

The MSIN is also used by the MNO to track the subscriber's usage and billing information. When the subscriber makes a call, sends a message, or uses data services, the usage information is associated with their MSIN. This information is then used by the MNO to bill the subscriber for their usage.

In addition, the MSIN is also used to enable various services, such as roaming. When a subscriber travels to another country and uses their mobile device, the device sends a signal to the nearest base station, which in turn sends a signal to the MNO's core network. The core network then uses the subscriber's IMSI to identify the subscriber and determine if they are authorized to use the network. If the subscriber is authorized, then the MNO can provide various services to the subscriber, including voice calls, messaging, and data services.

Another use of MSIN is for mobile number portability. When a subscriber switches from one MNO to another while keeping the same phone number, the MSIN remains the same. This allows the new MNO to identify the subscriber and activate their services without the subscriber having to change their phone number.

MSIN and SIM Security

The Mobile Subscription Identification Number (MSIN) is stored in the subscriber identity module (SIM), which is a small card that is inserted into the mobile device. The SIM is a critical component of the mobile telecommunications network as it stores the subscriber's authentication information and enables the subscriber to access the network.

The SIM is also an essential component in ensuring the security of the network. The SIM contains various security features, including encryption keys, which are used to secure the communications between the mobile device and the network. The SIM also provides authentication and identification information to the network, which helps prevent unauthorized access.

One of the primary security concerns with SIMs is SIM swapping. SIM swapping is a technique used by hackers to take over a subscriber's mobile phone number by convincing the MNO to transfer the number to a new SIM card. The attacker can then use the phone number to access the subscriber's accounts and steal their personal information.

To prevent SIM swapping, MNOs have implemented various security measures, including requiring additional authentication information before transferring a phone number to a new SIM card.

Conclusion

The Mobile Subscription Identification Number (MSIN) is a unique identifier that is assigned to a mobile subscriber. It is part of the International Mobile Subscriber Identity (IMSI) and is used to identify and authenticate the subscriber to the mobile network operator (MNO). The MSIN is generated by the MNO and is unique to each subscriber. It is stored in the subscriber identity module (SIM), which is a small card that is inserted into the mobile device.

The MSIN is a crucial component of the mobile telecommunications network. It enables the MNO to provide various services to the subscriber, including voice calls, messaging, and data services. It is also used by the MNO to track the subscriber's usage and billing information and to enable various services, such as roaming and mobile number portability.