International Mobile User identification code (imsi) International Mobile Subscriber Identity

International Mobile User identification code (imsi) International Mobile Subscriber Identity

The number assigned by a mobile user is uniquely identified internationally.

Technically speaking, imsi can completely solve the problem of international roaming. However, because a large number of AMPS Systems in North America still use min numbers, and MDN and min in North America use the same number, the system cannot be changed. Currently, international roaming is dominated by Min. The min resources with the O and 1 headers are referred to as the international roaming min, which is centrally managed by ifast (International Forum on ANSI-41 standards technology. Currently, China Unicom's request for the resource is directed at 09. As we can see, with the increase of users, the min resources used for international roaming will soon run out, and it is imperative to globally use imsi to identify users.

Imsi has a total of 15 digits, and its structure is as follows:

MCC + MNC + min

MCC: Mobile country code, mobile country code, 3 digits in total, 460 for China;

MNC: mobile network code, mobile network code, two digits in total. The China Unicom CDMA system uses 03. A typical imsi number is 460030912121001;

Min has a total of 10 digits, and its structure is as follows:

09 + m0m1m2m3 + ABCD

Among them, the m0m1m2m3 and the h0h1h2h3 in the mdn number can have a correspondence relationship, and the four bits of ABCD are freely allocated.

We can see that imsi has added MCC before the min number to differentiate the countries where each user is from, so that it can implement international roaming. In the same country, if there are multiple CDMA operators, they can be differentiated through MNC.



International Mobile Station identity-international mobile station ID