Section: 4.3.1.1 TMSI reallocation initiation by the network
Content: The network initiates the TMSI reallocation procedure by sending a TMSI REALLOCATION COMMAND message to the mobile station and starts the timer T3250. The TMSI REALLOCATION COMMAND message contains a new combination of TMSI and LAI allocated by the network or a LAI and the IMSI if the used TMSI shall be deleted. Usually the TMSI-REALLOCATION COMMAND message is sent to the mobile station using a RR connection in ciphered mode (see 3GPP TS 43.020[ Security related network functions ]  [13] and 3GPP TS 33.102[ 3G security; Security architecture ]  [5a]).