What is a MSISDN?
On a cellular network, MSISDN (Mobile Station Integrated Services Digital Network) is the phone number which identifies a device during calls or data sessions. It performs a crucial function in ensuring secure connectivity between the different components within an IoT network.
What is an MSISDN?
When you make a call on your mobile, there needs to be an effective way of connecting you to the right recipient, and that recipient needs a way of identifying you. The same applies to one device linking up with another on an IoT network.
This is where an MSISDN is crucial. It is the unique number that identifies a subscriber on a network.
The exact length of an MSISDN varies from country to country, depending on the numbering procedures set by local regulatory bodies. Typically however, it is 14 or 15 digits long (15 is the maximum). It is made up of three elements:
- Country Code (CC)
- National Destination Code (NDC)
- Subscriber Number (SN): This is the part that is unique to each subscriber.
What is the difference between an MSISDN and an IMSI?
The main difference between an MSISDN and an IMSI is:
- The MSISDN is the full “phone number” for a device.
- The IMSI is basically a technical identifier, used by the network operator.
Both of these numbers are types of identifiers; each performing a distinct role.
The international mobile subscriber identity (IMSI) is a 15-digit number that enables the network operator to identify subscribers. It is stored on the SIM (subscriber identity module). If a SIM is moved from a device, the IMSI moves with it. You cannot dial up an IMSI. These numbers are used mostly by operators for network management purposes: e.g. for checking the location of users.
MSISDNs are much more focused on facilitating connections between users and devices. Unlike an IMSI, MSISDNs are not bound to a particular SIM. They can be transferred from device to device and SIM to SIM. You can even have multiple MSISDNs associated with the same SIM or device.
Benefits of MSISDN
In any system of interacting devices, you need a means of identifying and differentiating between different devices. MSISDN is an effective, globally-recognised way of achieving this.
Disadvantages of MSISDN
Although the transferability of MSISDNs can be beneficial, it can also pose a risk. Device and SIM management is therefore important especially so with large numbers of devices. If it’s managed through a dedicated IoT portal and service provider all of this can be handled securely and automatically.