The International Mobile Subscriber Identity(imsi)

The international mobile subscriber identity(IMSI) is a unique number, usually is using the fifteen digits and associated with Global System for Mobile Communication(GSM) and Universal Mobile Telecommunications System (UMTS) Internet phone users. TIMSI is a unique number that identifies GSM subscribers.

The number are separate 2 parts. The initial part consists of six digits in the North American standard and five digits in the European standard. For the second part is allocate for the network operator to uniquely identify the user.

The IMSI is store the user identity module (USIM) is inside the phone and is sent over the phone to the appropriate network. The IMSI is used to obtain details of the mobile device in the Home Location Register (HLR) or Visitor Location Register (VLR).

When the phone is associated, the temporary of IMSI is allocated and used to identify users in future exchanges. This is embedded in the mobile device’s SIM and is provided when the networks are accessed. It is transmitted during the initialization. It will to prevent the user from the being identified and tracked by eavesdroppers on a radio interface, the IMSI is short transmitted. Randomly to generate The Temporary Mobile Subscriber Identity (TMSI) is sent instead of the IMSI to ensure the identity of the mobile user remains confidential and eliminates the need to wirelessly transmit it over the radio link in an unencrypted manner.

The IMSI is stored as a 64-bit field on the phone’s SIM card. The IMSI is associated with mobile networks interconnected with other networks, particularly CDMA, GSM and EVDO networks. This number is provided directly on the phone or R-UIM card.

The three components in IMSI are the Mobile Country Code, Mobile Network Code and Mobile Subscriber Identification Number. The IMSI’s mobile country code has a similar meaning and format to the location area identifier. The mobile web code has the same format and meaning as the location area identifier and is assigned by governments. Mobile Subscriber Identification Number Identifies the mobile subscriber and is assigned by the operator.

When the mobile station is powered on, they perform a location update procedure by indicating their IMSI to the network. The first location update process is called the IMSI attachment process. The mobile station also performs a location update to indicate the current location when moving to a new location area. The location update message is sent to the new VLR, providing the location information to the subscriber’s HLR. Regularly updated regularly. If the mobile station is not registered after the update period, the mobile station is not deregistered. The IMSI detachment procedure informs the network that the mobile station is no longer connected when the mobile station is down.