The Mobile Subscription Identification Number (MSISDN) is a fundamental element in the mobile telecommunications system, serving as a unique identifier for every mobile phone subscription worldwide. It includes components that denote the country code, network code, and the subscriber's unique identification number.

Key components and structure of an MSISDN include:

Country Code: The country code is a numerical prefix that identifies the country where the mobile subscriber is registered.

Network Code: The network code represents the specific mobile network operator (MNO) to which the subscriber is connected.

Subscriber's Unique Identification Number: This portion of the MSISDN identifies the individual subscriber within the specified country and network.

The MSISDN allows for globally standardized mobile network identification, ensuring that each mobile subscription has a unique identifier that facilitates communication and connectivity across various networks and regions.

Examples of MSISDNs include phone numbers like +1 123 456 7890, where +1 is the country code for the United States, 123 represents the network code for a particular mobile operator, and 456 7890 is the unique subscriber identification number.

Understanding and utilizing MSISDNs is fundamental for telecommunication operators, network infrastructure providers, and mobile service developers to ensure effective communication and connectivity within the global mobile telecommunications network.