Question: Which entity sends the P-TMSI Reallocation Complete message to indicate that reallocation of a P-TMSI has taken place?
Option 1: Network to MS (Mobile Station)
Option 2: MS (Mobile Station) to network
Option 3: SGSN (Serving GPRS Support Node) to GGSN (Gateway GPRS Support Node)
Option 4: HLR (Home Location Register) to VLR (Visitor Location Register)
Explanation: The P-TMSI Reallocation Complete message is sent by the MS (Mobile Station) to the network, indicating that reallocation of a P-TMSI has taken place. This message is used in the context of GPRS (General Packet Radio Service) and is essential for maintaining mobility management and session continuity.